1. Compare Antheridial and Archegonial branches in Funaria.
2. Describe the internal structure of Funaria capsule.
3. Describe the internal structure of Pteris rhizome.
4. Describe reproduction in Pteris sporophyte.
5. Describe the reproduction in Pteris gametophyte.
6. Describe the internal structure of Cycas leaf-let.Mention xerophytic adaptations
7. What is Plant improvement?Describe its aims and objectives.
8. In which type of plants Mass selection,Pureline selection and Clonal selection
Can be performed.With examples,describe their advantages and disadvantages.
9. What is Hybridization?With suitable examples,describe different types in it.
10. Explain briefly steps involved in tissue culture technique?.
11. Describe Co2 fixation in C3 plants.
12. Describe Biochemical reactions occurring in Mitochondrial matrix.
13. What is Hybridization ?Describe various stages in it.
14. What is Glycolysis?Describe the sequence of reactions occurring in it.
15. What is Bio-technology?Describe the process of Recombinant DNA technology.
16. What is Selection?Describe various types,advantages and limitations in it.
17. Describe light phase in Photosynthesis.
18. Describe Electron transport occurring in Mitochondria cristae.
19. Describe the mechanism of Protein synthesis.

Short Answer Questions .4 marks.

1. Describe the cell structure of an autotrophic thallophyte.
2. Bring out the differences between Scalariform conjugation & Lateral conjugation in Spirogyra.
3. Bring out the differences between gametophore and protonema of Funaria.
4. Explain Transformation in Bacteria..
5. Differenciate between viroid and virion with two examples each.
6. Explain Field capacity and Permanent Wilting percent.
7. What are the important features and properties of Restriction endonucleases..
8. What is Hybrid vigour?Mention reasons for it.
9. Describe the role of induced mutations in crop improvement.
10. What are the differences between Auto tetraploids and Allotetraploids.
11. Differenciate between spontaneous mutations and induced mutations.
12. What is Emasculation?Why is it done in plants.
13. What is Synthetic genus?Giving two examples explain how they are to be formed.
14. Briefly describe Embryo sac culture and its advantages.
15. What is C-DNA and what are its advantages.
16. Describe three types of Transpiration.
17. “Transpiration is a necessary evil”-explain.

--2--
18. With a neat labeled diagram describe the structure of a Bacteriophage.
19. Bring out the differences between Rust and Smut disease.
20. Discuss the role of Auxins in plants.
21. Describe the importance of tissue culture in plants.
22. Describe various horizons in the soil as seen in soil profile.
23. What is the main force causing Osmosis.Explain it with experiment.
24. Describe the role of Gibberellins in the field of Agriculture and Horticulture.
25. Describe the disease and control measures of plant disease,showing symptoms when panicle emerges out.
26. Describe a Bacterium cell.
27. Classify Viruses based on the nature of host.
28. Describe the symptoms of Blast of Rice disease.
29. Describe the opening and closing mechanism of stomata in plants.
30. Describe the disease symptoms of Citrus canker.
31. Describe various green manure fertilizers.
32. Describe the role of Gibberellins in plants.
33. Describe Dioecious conjugation in Spirogyra.
34. Bring out the differences between C3 & C4 plants in Co2 fixation.
35. Write the name of pathogen,name of disease causing in sugarcane.Describe the symptoms and control measures.
36. Write about active absorption of ions..
37. What is Ascent of Sap?How can you explain it in tall trees,by Cohesion and Tension theory.
38. Wite about Bio-fertilizers.
39. Write about the physiological effects of Cytokinins in plants.
40. What are transgenic plants?What are their advantages.
41. Based on shape and arrangement classify various types of Bacteria.
42. Write short notes on conjugation in Bacteria.
43. What is Kranz anatomy?What is its importance in plants.
.

--3--

VSA Questions.& answers

1. Bring out the difference between holdfast and vegetative cell of Spirogyra?
holdfast=without chloroplast,cannot divide.
Veg.cell=chlorophyllous,shows cell division.
2. Why Spirogyra is called Pond silk and Pond scum?
Pond silk—pectin cellwall becomes mucilage forming slimy to touch.
Pond scum—formsfree floating entangled mass of fine filaments.
3. What will happen in Spirogyra when gametes fail to fuse in conjugation.
Gamete form resting spores with thick cell wall by parthenogenesis.
4. Where in zygospores seen in Spirogyra during isogamous and physiologically
anisogamous conjugation.
Isogamous=filaments show empty cells,zygospore in conjugation tubes.
Physiological anisogamy=Male filament with empty cells,female filament with zygospores.
5. Why Rhizopus is called Bread mould and Black mould?
Bread mould=forms cottony mycelium on stale bread.
Black mould=mycelium produces dark colored sporangia.
6. Why Rhizopus is called Pin mould and Weed of Laboratory?
Pin mould=sporangiophore with globose sporangia looks like pin head.
Weed of laboratory=commonly contaminates microbial cultures.
7. What is meant by “zygophore”,”zygote”,”zygospore”,”zygosporangium”?
Zygophore=hypha that forms progametangium
Zygote=formed by the fusion of two gametangia.
Zygospore=the diploid spore formed in the zygosporangium.
Zygosporangium=formed by the union of two gametangia,develops dark,thick outer coat.
8. Differenciate Paraphysis from apophysis?
Paraphysis=filamentous,multicellular,uniseriatesterile hairs intermixed with antheridia and archegonia in Funaria.
Apophysis=assimilatory basal part of capsule in Funaria.
9. What is calyptra in Funaria? What is its function ?
Around the growing embryo,venter wall remains as protective cover forming
Calyptra.It forms a lid over the capsule.
10. What is a Dictyostele?
The dissected stele embedded in parenchymatous ground tissue.exteris rhizome.
11. What is transfusion tissue?
Special lignified cells formed around the vascular bundle form primary transfusion cells,which laterally develop in the mesophyll form secondary transfusion tissue with bordered pits.ex:Cycas leaf-let.
12. What is false indusium?
The infoldings of sporophyll protecting the sori .Exteris.

--4--
13. What are Girdle leaf traces?
Indirect leaf trace from the vascular bundle,bifurcates,encirculates stele,
before entering the leaf.
14. What doyou understand byPseudomesarch vascular bundle.?
Vascular bundle with exarch centripetal xylem,& endarch,centrifugal xylem.
15. Which organisms are refered to as “Scavengers of Nature” and why?
Bactria decompose dead decaying plants and animals,converting complex organic matter into simple substances.
16.What is Lysosome ?What is its function?
Enzyme secreted by Bacteriophage,to degenerate the host cellwall to inject its
nuclic acid.
17. Differenciate between pathogenesis and pathogenicity?
Pathogenesis=sequence of metablic changes bringing out the disease.
Pathogenicity=capability of pathogen causing disease.
18. Name the fungi causing Bengal famine and Irish famine?
Bengal famine=Brown leaf spot.Helminthosporium oryzae.
Irish famine=Potato blight.Phytophthora infestans.
19. Why does the juice from infectedsugarcane give bad odour?
Sucrose in infected cane turns to glucose and to alcohol .
20. How Mushrooms are helpful in providing food to plants in forests?
Mushrooms disintegrate the plant material on which they grow and make the nutrients available to the plants in forests.
21. What is crop rotation ?Give one example.
Planting unrelated,resistant crops,from season to season,to avoid pathogen specificity.ex:damping off.
22. Why is Blast of Rice called “Neck Blast”?
Infected neck of the panicle is blackened due to grey,fluffy mycelium.
23. Differentiate between Litter and Guff?
Litter=recently fallen organic debris on the ground.
Duff=partially decomposed organic matter beneath the Litter.
24. Which type of soil is best suited for plant growth and why?
Loamy soil.equal ratios of sand,silt and clay.Much water holding capacity,aeration and rich in minerals.
25. Define Imbibition?Why do Pea seeds show more imbibition than wheat seeds?
Absorption of water by hydrophilic colloids is called Imbibition.
Proteins have high imbibing capacity than carbohydrates.Proteinaceous Pea seeds swell more on imbibition than starchy wheat grains.
26. Define Symport and Antiport?
Symport=transport of anions and cations in the same direction by carriers.
Antiport=transport of ions in opposite direction.
27. Define Absorption spectrum and Action spectrum?.
Absorption spectrum=a graph showing the absorption of lightby pigments at different wavelengthsIt is measured by Sphectrophotometer.
Action spectrum=a graph showing the rate of photosynthesisat different wavelengths..
--5—

28. What is Colchicine?Write its source and use.
Alkaloid used in doubling the chromosome number.It is obtained from the corms of Colchicum autumnale.
29. What is Triticale?
Synthetic genus made by a cross between Trticum aestivum and Secale cereale
developed by Polypliody breeding.
30. List out different selection methods for hybridization in self pollinated crops.
Pedigree method,Bulk method,Back cross method.
31.What is RUBISCO?Comment its importance in photosynthesis?
RUBISCO=Ribulose 1,5,bis phosphate carboxylase/oxygenase.
Most abundant soluble protein in plant leaves.Helps in the reaction
Of Co2 acceptence by RuBP to form stable compound PGA.
32.What is micropropagation ?
In vitro growing of plant cells, tissues and organs .
33.What is the nutritive value of mushrooms?
Vit.B,Folic acid,vit.B12,Pantothenic acid,ascorbic acid,amino acids
Lysine,Tryptophane,precursors of vit.A and D,minerals P,K,Fe,Cu.
34.Define Single Cell Protein and give two examples .
The purified cell biomass of unicellular organisms forming protein source.
Spirulina,Yeasts.
35. What is rDNA technology?Give two examples of its application in the field of
medicine.
Isolation of specific gene and insertion of it in another organism through
vector to express its native characters.ex.humilin,gene therapy.
36. Differentiate turgid cell from flaccid cell.
The cell with turgor pressure is called turgid cell.The cell with reduced turgor
Pressure due to loss of water is called flaccid cell.
37. Which substance is called connecting link betweenGlycolysis and Kreb’s
cycle?How many carbon atoms are present in it?.
Acetyl CoA. 2 carbon atoms..
38. What are the two objections for Cohesion-Tension theory.?
a)embolism=formation of gas bubbles in xylem obstructing the continuity
of water.b)tracheids are the conducting channels.During evolution vessels
eliminate tracheids
39. What is the difference between Transpiration and evaporation?
Transpiration=loss of water in the form of water vapour from the aerial
Parts of the plant.
Evaporation=loss of water in the form of vapour directly from water
Into the atmosphere.
40. How many macroelements are required for plant growth.What are they.
9-C,H,O,N,P,K,Ca,Mg,S.
41. Define apoenzyme and holoenzyme.
Apoenzyme=protein part of enzyme.
Holoenzyme=apoenzyme and cofactor together called.
--6--

42. Mention the primary acceptor of Co2 in C3 and C4 plants.
C3 plants=RuBP(Ribulose Bis Phosphate)
C4 plants=PEP(Phospho Enol Pyruvate).
43. Why C4 plants are more efficient than C3 plants?
C4 plants assimilate two or three times more Co2 than C3 plants.
Photorespiration will not take place in C4 plant
44. Name the pigment present in the root nodule of legumes and give
Its function.
Leghaemoglogin.it regulates theavailability of Oxygen,protecting the
Nitrogenase in the bacteroid.
45. “The Genetic code is non-overlapping” elaborate.
No single base can take part in the formation of more than one code.
46. What is Richmond-Lang Effect.
The ability of cytokinins to delay the process of senescence.
47. Where does Oxidative Phosphorylation occur?What are its components?
On inner mitochondrial membrane. 3 components namely FMN,FAD,Cyt a, Cyt b, Cyt c..
48. Differentiate Plasmids from Cosmids.
Plasmids=small circular DNA,with 25to30 genes,extra nuclear in protoplasm,
With antibiotic resistant genes.
Cosmids=plasmids with cos sites that canbe introduced in phage capsids.
49. Explain Hill reaction.
Lysis of water releasing O2,in the presence of hydrogen acceptor,
When chloroplasts are illuminated.
50. Define diazotrophy? Give example..
Dinitrogen fixation by living organisms is called diazotrophy.Nostoc,Anabaena..
51.Write terminator codons and their function.
UAA,UAG,UGA.they help in terminating the polypeptide chain synthesis.
52. What is molecular farming?
Using Transgenic plants as bioreactors for getting specialized medicines,chemicals,and antibiotics.
53. What are nif genes?.What is the enzyme coded by it?
Prokaryotic cell genes responsible for biological nitrogen fixation are called nif genes. Dinitrogenese.
54. Define the turn over number of an enzyme.
Number of moles of substrate converted into product,by one mole of enzyme per minute.
55. Differentiate the cell structure of Spirogyra and Rhizopus.
Spirogyra=uni nucleate,cellulose cell wall,starch reserve
Rhizopus=coenocyte,chitin cell wall,Gycogen,oil globules reserve.

--7--

56. How can you differetiate the antheridial cluster from archegonial cluster
In Funaria.
Antheridial cluster=terminal,with perigonium form moss flower,lateral later.
Archegonial cluster=lateral,with perichaetium,terminal later.
57. What do you understand by “peristome”
Two whorls of 16 hygroscopic teeth in each circle,in operculam of Funaria
Capsule ,helping in the dispersal of spores.
58. What do you understand by the terms-annulus and stomium?
Annulus=ring of vertically elongated cells helping in the dehiscence of
Sporangium in Pteris.
Stomium=small,flat,thin walled ,radially elongated cells,with upper epistomium and lower hypostomium,helping in the cleavage of sporangium
59.Mention the difference between the anatomy of coralloid root and normal root.
Normal root=resembles dicot root,xylem diarch or tetrarch.
Coralloid root=shows algal zone with Nostoc,Anabaena(blue green algae),
Xylem triarch.
60. Which bacterium produces “gobar gas” and how?
Methanococcus,Methanobacillus anaerobically ferment dung and produce
Methane gas,(gobar gas).
61. Define Shelf life and Vase life ?Give the hormone substances promoting it?
Shelf life= storage period without loss of freshness in vegetables.Cytokinin.
Vase life=period of freshness of flowers in a flower vase. BAP.
62. Explain the term Amphidiploid.
Allotetraploid containing two diploid sets of chromosomes of two different
Species or genera of the same family.
63. What are the causes and remedies of inbreeing depression?
Considerable loss of vigour in hybrid due to continuous self pollination
Segregation of genes and homozygosity are causes.
Crossing in bred lines,heterozygosity are remedies.
64. Write an account on interspecific hybridization.
Crossing two species of the same genus.Disease and drought resistance canbe
Achieved.Ex;Red plum in tomato=Lycopersicum esculentum x L.pimpinellifolium.Devi Raj cotton=Gossypium hirsutum xG.arboreum.
65. Mention the important varieties,type of hybridiztion by which Jaya,Padma
Varieties in Rice are achieved.
Intervarietal(intraspecific) hybridization.
T.N.1 x T.141 =Jaya.;T.141 x T.N.1 =Padma.
66. Who coined the word Heterosis.State the imporatant causes for it.
The superiority of the hybrid over the parents in size and vigour.
G.H.Shull coined Heterosis.
Causes:dominance hypothesis;over-dominance hypothesis.

--8--

67. How are artificial ployploids produced?
a)cold treatment of zygote in dividing state. b)applyingacenaphthene,colchicines,coumarin to vegetative,floral buds.
c) subjecting vegetative,floral buds to X rays.
68. How are Mutations induced?
X-rays,alpha-rays,beta-rays,gamma rays(ionizing),UV rays(non-ionizing)
Colchicines,nitrogen.mustard gas,formaldehyde,ethyl methane sulphate,
Methyl methane sulphonate,malic hydrazide(chemical mutagens)
Induce mutations.
69. Define RQ?Why RQ value for fats is less than zero?
The ratio of Co2 liberated to the O2 absorbed is called R.Q.
For fats,Co2 released is less than O2 consumed.R.Q=57/83=0.69.
70. Name the auxins that act as herbicides.
2,4,dichlorophenoxy acetic acid (2,4-D).
2,4,5-trichloro phenoxy acetic acid (2,4,5-T).
71. What is meant by “triple response growth”?
Inhibiting elongation of growth,inducing lateral growth and causing transverse geotropism by Ethylene.
72.Why Spirogyra is slimy when kept in water?
Pectose part of the cell wall becomes mucilage sheath with water.
73. Mention the major types of cultivated mushrooms in India.
White button mushroom—Agaricus bisporus.
Oyster mushroom--- Pleurotus sojar-caju.
Paddy straw mushroom-- Volvariella volvacea.
74. Why the rate of transpiration is more in Sorghum than in maize ?
Sorghum has more root-shoot ratio than maize.Rate of transpiration increases with an increase in root-shoot ratio.
75. What is senescence?How can leaf senescence can be delayed?
Aging process in plants.Cytokinins BA,BAP.
76. Define Glycocalyx? Into how many layers it is differentiated?
Layer lying outside the Bacterial cellwall is called Glycocalyx.Two layers.Polysaccharide made loosely formed Slime layer,thick tough Capsule layer.
77. Describe apogamy in Pteris.
Apogamy is the development of sporophyte from gametophyte without syngamy.Sporophytes will be haploid.
78. Define single cell protein ?Give two examples.
The purified dried cell biomass of unicellular organisms forming protein source is called SCP.Spirulina,Chlorella,yeasts.
79. What is meant by apical dominance?Name the phytohormone that causes it.
Actively growing apical buds dominate and inhibit the growth of axillary buds.
Auxins show apical dominance.

--9--

80. What is the difference between active and passive absorption.
ATP is utilized in active absorption.,not in passive absorption.
81. What is meant by Heterothallism?Who discovered it first in Rhizopus?
It is the condition of the mycelium ,morphologically alike,but physiologically different in having two different strains.
A.F.Blakeslee observed it in Rhizopus stolonifer.
82. Define Emerson enhancement effect?
When shorter and longer wavelengths are used simultaneously the
Photosynthetic yield is more,than when the individual lenths are used.
83. Write the name of the alkaloid that enable the doubling of chromosome
number.Where from it is obtained.
Colchicine prevents the spindle formation during metaphase of meiosis
And enables doubling of chromosomes.it is derived from the corms of
Colchicum autumnale.(Fam:Liliaceae).
84.Write any two deficiency symptoms of Potassium.
Chlorosis followed by necrosis in margins and tips of leaves.
Shortened internodes.Phloem mobile ,first appear in older leaves.
85. Write about the Paraphyses in Funaria.
Intermixed with antheridia and archegonia multicellular,uniseriate,filamentous sterile hairs are called paraphyses.They conserve moisture and protect the organs.

.

Comments

1 2 3 4 5 6 7 8 9 10 11 12
d a b b d a b a c a b c

13 14 15 16 17 18 19 20 21 22 23
a c a a b a b b b b d

24 25 26 27 28 29 30 31 32
c b a a d c a c a

33 34 35 36 37 38 39 40 41
c c b a a a c c d

42 43 44 45 46 47 48 49 50 a d a c c b c a c

51 52 53 54 55 56 57 58

c c c a b b c c

Comments

PLANT KINGDOM.

1) Describe sexual reproduction process in Funaria.
2) Describe the internal structure of capsule in Funaria.
3) Describe the internal structure of rhizome in Pteris.
4) Describe asexual reproduction in Pteris.
5) Describe sexual reproduction in Pteris.
6) Describe the internal structure of primary stem in Cycas.
7) Describe the T.S.of Cycas leaf-let.Mention the xerophytic adaptations in it.
8) Describe the vertical section of ovule in Cycas.

PLANTS-HUMAN WELLFARE:

9) What is “Hybridization”? Describe various types in it.
10) What is “Selection”? Describe three types in it.
11) Describe various phases in Genetic Engineering process.

PLANT PHYSIOLOGY:

12) Briefly describe Co2 fixation mechanism in C3 plants.
13) What is “Glycolysis”? Describe the sequence of reactions in it.
14) Describe Citric acid cycle in plants.
15) Describe Electron Transport in Respiration.
16) Describe in detail Protein synthesis mechanism in plants.
17) What is Seed Dormancy? Describe reasons and breaking methods in it.
18) Describe the physiological changes of Auxins in plants.

SHORT ANSWER QUESTIONS:

PLANT KINGDOM:
1) Write the differences between Scalariform and Lateral conjugations in Spirogyra.
2) Describe sexuality in Rhizopus.
3) Describe Gametophore development from spore in Funaria.
4) Describe the structure of Prothallus in Pteris.
5) Describe the external & internal morphology of Coralloid roots in Cycas.

MICROBIOLOGY:
6) Compare the cellwalls of Gram + ve & Gram _ve bacteria.
7) Write short notes on Conjugation in Bacteria.
8) Describe the features of plant diseases caused by Viruses.
9) Differentiate between Lytic and Lysogenic life cycles .
-2-

PLANT PATHOLOGY:

10) What are the symptoms of Blight disease.
11) How Red Rot disease can be identified.
12) How Grain Smut disease spreads? What are the control methods.
13) Describe the disease symptoms of Citrus Canker.

PLANTS-ENVIRONMENT:

14) Differentiate between Physical and Physiological xerophytes.
15) Describe morphological adaptations in Hydrophytes.
16) Differentiate between Rain forests and Monsoon forests.
17) Describe the agricultural methods applicable in Soil conservation.

PLANTS-HUMAN WELLFARE:

18)What is Hybrid Vigour?Describe reasons for it.
19) What is Para sexual (Somatic) hybridization?What are its advantages.
20) Define Plant introduction and Acclamatisation?Give the names of the plants directly introduced.
21) What are Synthetic Seeds?How they are prepared?
22) What is Spawn?How it is prepared?
23)What is the importence of Somatic Hybrids?Give examples.

PLANT PHYSIOLOGY:
24) Define and explain Field capacity and Permanent Wilting Percentage.
25) Write an account on Plasmolysis.
26) Describe Cohesion and tension theory.
27) Describe stomata closing and opening mechanism.
28) Briefly describe Cytochrome Pump theory.
29) Describe the deficiency symptoms of Phosphorous in plants.
30) What are the advantages of using Biofertilizers.
31) Briefly describe the properties of Enzymes.
32) Differenciate C3 and C4 plants in fixing Co2.
33) What is the role of Peroxisomes in Photorespiration.
34) Write a short note on CAM pathway.
35) Differenciate between Aerobic and anaerobic respiration.
36) Explain the Physiological changes of Gibberellins in plants.
37) How Cytokinins affect the plants growth.
38) Describe the Physiological changes of Abscisic Acid in plants.
39) Describe the role of Ethylene in plants growth.
40) Describe the reasons for seed dormancy in plants.

--3—
1. Explain the process of sexual reproduction in Funaria?

Funaria is monoecious.Antheridia occur at the tip of main stem and Archegonia at the tip of lateral branches.Funaria is protandrous.

Male shoot or Antheridial branch or antheridiophore:Around the antheridia perichaetium forms moss flower.Antheridia are mixed type.Intermixed with antheridia uniseriate green filaments paraphyses protect antheridia against dry condition.

Antheridium: Stalk is multicellular,biseriate.Club shaped antheridium has one celled thick jacket layer and one or two terminal cover cells.Jacket encloses mass of androgonial cells.Each forms androcyte mother cell, that divides obliquely forming two androcytes.Each androcyte formssickle shaped biflagellate antherozoid with two equal flagella and distal blepharoplast.Antherozoids are liberated en masse,swim and reach archegonia.

Archegonial branch or archegoniophore:Archegonia are surrounded by perichaetia and intermixed withmulticellular uniseriate sterile hairs paraphyses.Archegonia are mixed type.

Archegonium:It has multicellular.multiserite stalk,double layered swollenventer,long twisted neck.Venter encloses egg cell below,venter canal cell above.Neck is made of six vertical rows of cells enclosing six or more neck canal cells.Neck has four cap cells.In matured archegonium,venter canal cell,neck canal cells disintigrade forming mucilage.

Fertilization:When cap cells open,mucilage exudes out attracting antheridia.By Chemotactic movement antherozoids reach venter.One antherozoid fuses withegg cell resulting in diploid zygote.

2. Describe the internal structure of Funaria Capsule?

Diploid zygote develops into sporophyte.It is partially dependent on gametophore for water and salts.It is separated into foot seta and capsule.

Capsule: It is organized pear shaped structure.It is concerened with spore production and spore dispersal.Capsule shows basal apophysis,middle theca and upperpart operculum

Apophysis:It is swollen,basal green part of the capsule.It has central strand with conducting tissue.It consists of narrow,vertical,colorless thin walled cells.It is connected with the central strand of seta.Around the central strand,spongy

--4—

chlorenchymatous cells with intercellular spaces is present.Single layered epidermis with stomata is present on the outerside.

Theca: Urn shaped middle part of the capsule.It is spore producing region.Outermost layer is epidermis with few stomata.Hypodermis is two layered parenchyma compactly arranged.Below this spongy parenchyma is one or two layered.Narrow elongated filaments trabeculaeconnect the outer sporesac with chlorenchyma through space.In between the two to three layered outer sporesac andsingle layered inner sporesac,sporogenous cells form spore mother cells.By meiosis each spore mother cell forms spore tetrad,that separates into four haploid spores.At the cetre compact colour less parenchyma forms collumella.

Operculum: It is cap like structure above the theca.It is separated from operculum by two rings of cells.Lower ring,rim is 2 to 3 layered,with thick walled cells.Upper ring is annulus,madeup of 5 to 6 superimposed layers,with thickwalled cell layer, and lower thin walled cell layer.Radially arranged peristomial teeth are 32 in number,in two whorls of 16 each.Outer whorl of teeth are hygroscopiccontrolling the dispersal of spores from capsule

3. Describe briefly the internal structure of rhizome of Pteris?

T.S.of Pteris rhizome is oval in outline.It shows:

Epidermis: Outermost single layer.Narrow quadrangular cellshave cuticle on outerside.

Cortex: Multilayered.Hypodermis is 4 to 5 layered,sclerenchymatous.Inner cortex is broad,parenchymatous.leaf traces and root traces are present in cortex.

Stele: Dictyostele, with a ring of meristeles.Meristele is elliptical.It has outer single layered endodermis,with casparian bands on radial walls.Pericycle is 1 or 2 layered,made up of thin walled cells.Phloem has sieve cells and phloem parenchyma.Companian cells and phloem fibres are absent.In the center of meristele,xylem is in mesarch condition. Protoxylem is in the center,metaxylem
on eitherside.Xylem has tracheids,xylem parenchyma.Vessels are absent.

4. Write about the process of reproduction in the gametophyte of Pteris?

Sexual reproduction occurs in gametophyte.In Pteris gametophyte is also called Prothallus.Unicellular,uninucleate spore develops into gametophyte.
--5—

Structure of Prothallus: Heart shaped dorsiventral,shortlived,green,autotrophicthallus like structure is called Prothallus.It has apical notch,below whichmany celled cushion likemidregion containsArchegonia on the ventral side.On the posterior side intermixed with rhizoids Antheridia are present.Rhizoids fix the thallus,absorb water and minerals.Prothallus contain thin walled polygonal parenchyma cells with discoid chloroplasts.Cytoplasm is in the form of primordial utricle.Intercellular spaces are absent.Prothallus is monoeciouswith archegonia and antheridiaon ventral side.They protrude to dorsal surface.

Antheridia: Small,sessile,globular,antheridium has first basal ring cell,middle second ring cell,and top cap cell.Antheridium wall enclosesandrocytes.Each androcyte forms long multiciliateantherozoid with a prominent posterior vesicla.Antherozoids are liberated en masse.

Archegonia: Flask shaped.The swollen base venter is enclosed in prothallus.Short slender neck projects out.Venter encloses egg,above which there is venter canal cell.Neck has 4 vertical rows of neck cells.Neck canal cell is single with two nuclei.At maturity ,venter canal cell,neck canal cell disintegrate forming mucilage,that exudes out .It contains Malic acid.Spermatozoids enter neck canal.One spermatozoid fuses with egg forming diploid zygote.
------------------------------------------------------------------------------------------------

5. Describe the internal structure of the leaf-let of Cycas and list out the xerophytic adaptations seen in it ?

T.S.of leaf-let shows:

Epidermis: Outermost layer,separated into upper epidermis and lower epidermis.Cuticle is on the outer surface .Sunken stomata are on the lower epidermis.

Mesophyll: It is the ground tossue present between upper and lower epidermal layers.Hypodermis on eachside is made up of Sclerenchyma,more layered in the midrib region.It protects leaf from overheating and transpiration.Below hypodermis of upperepidermis,palisade tissue consists of columnar cells with more chloroplasts.It is assimilatory in function.Spongy tissue lies inner to lower epidermis.Irregular loosely arranged cells with intercellular spaces.,with chloroplasts.This tissue helps in assimilation and aeration.Trasfusion tissue is present between palisade and spongy parenchyma.It develops from the midrib and reaches the end of the leaf margin.Primary transfusion tissue is specialized tracheid like parenchyma cells with bordered pits.Secondary transfusion tissue develops from this.These are long elongated,thickwalled,helping in lateral conduction of water and salts.
--6--

Vascular bundle: Central vascular bundle is surrounded by Sclerenchymatous bundle sheath.Vascular bundle is conjoint,collateral and open.Xylem is diploxylic,having centripetalxylem above anf centrifugal xylem below.Phloem is below xylem.Inbetween cambium is non-functional.

Xerophytic adaptations:

1.Epidermis with thickwalled cells.cuticle on outerside. 2.Scerenchymatous hypodermis. 3.Sunken stomata. 4.Presence of transfusion tissue.5. poorly developed spongy parenchyma.

6.Describe the structure of megasporophyll and ovule of Cycas and explain the development of female gametophyte

Megasporophyll: Female cone is not formed.On the female plant megasporophylls are loosely arrangedaround the stem tip.Growth of the female plant is monopodial,as the stem tip growth is continuous.Megasporophyll is ovate,flattened dorsiventral structure.It has lower stalk,middle fertile part bearing ovules in 1 to 6 pair4slaterally,upper part is sterile,pinnalike.

Ovule or Megasporangium: Cycas ovule is the largest ovule in plantkingdom.Orthotropous,Unitegmic.Single integument is separated into outer and inner fleshy Sarcotesta layers and the middle stony Sclerotesta layer.Outer and inner layers are vascularised.Integument leaves a pore.micropyle,throughwhichnucellus protrudes out forming nucellar beak.Some cells break forming a cavity called pollen chamber,in which pollen germinate.Integument encloses nucellus.One cell becomes archesporial cell that forms megaspore mother cell.By reduction division,linear tetrad of megaspores form.Lowest cell is functional.

Female gametophyte:Functional megaspore by free nuclear divisions form female gametophyte,followed by cellwall formation.The female gametophyte is also called endosperm.,nutritive in function.It is haploid formed before fertilization.A tiny space developedbetween nucellus and female gametophyteis called archegonial chamber.

Archegonium: Lining the archegonial chamber2-8 archegonia develop.Each archegonium has egg below and venter canal nucleus above.Venter is absent.Two celled neck is present without neck canal cells.Egg of Cycas is the largest in the plant kingdom

--7--

7.Explain the various methods of recombinant DNA technology ?

Recombinant DNA technology brings the transfer of desired gene from prokaryotic cell to eukaryotic cell or vice versa. Isolation of restrction endonuclease enzymes laid foundation to this process. A gene of interest in one organism,is isolated and is inserted into a vector. The desired gene multiplies along with vector gene. ex:Human insulin gene isolated and inserted in E.Coli bacterium,produce human insulin through the bacterium. By gene cloning technique multiple copies of the desired gene,develop in host bacterium. It is carried in computerized machine Thermocycler by a method called Polymerase chain reaction. The important methods in recombinant DNA technology are:

1 Isolation of a desired gene: Cellwall is digested by enzymatic action. Biological membranes are dissolved by high powered detergents. The protoplasmic mass is treated with phenols and nucleases. Pure DNA is isolated by gradient centrifugation. Nathans isolated restriction endonucleases These are also called molecular scissors,as they cut DNA molecule into a number of fragments. Blunt or flush ended fragments are DNA strands end at the same point.ex:
The straggered cuts show protruding ends.
The complementary base sequence at the two ends of a single strand is called
palindrome. Due to cohesive or sticky ends they join together ,when different
DNA are mixed. Restriction enzyme E.Cori recognises GAA sites and cut
in between G and A (G!A). The cut DNA fragments are separated from each
other by Gel electrophoresistechnique.The desired DNA fragments are selected
by Southern Blotting Technique.

2. Insertion of the isolated gene into a suitable vector: The process of insertion of
desired DNA fragment into suitable vector to get indefinete number of gene
copies is called gene cloning.The properties of ideal cloning vector are: 1) low
molecular weight.2)single sites for the activity of restriction enzymes 3) ability to
replicate truly inside a host cell 4) bearing antibiotic resistance.The vectors used
are:
Plasmids: Plasmid is extranuclear circular DNA with 25 to 30 genes.It can be
easily isolated and reintroduced in host cell.Other artificial popularly used
plasmid vectors arepBR 322(after Boliver & Rodriguez);PUC 19,101(after
University of California).
Phage vector:Lambda ( )phage.Most of the phage is not essential.Bacterium cell
is treated withEDTA (ethylene diamine tetra acetic acid ) and lysozyme,to digest
bacterium cellwall.Plasmid is isolated by centrifugation in Sodium lauryl sulphate
solution.The isolated circular plasmid DNA is cut into linear sticky ends,when
treated with restriction endonuclease.The two sticky ends of plasmid DNA join
with the ends of desired gene.DNA ligase joins it, by covalent
bonding,regenerating circular hybrid called Recombinant (r) DNA or chimeric
DNA.
--8—

3. Introduction of recombinant vector into the host: The recombinant DNA is transferred into suitable host cell ( E.Coli) by transformation.Transformed cells expressthe desired genes/Dilute solution of Calcium chloridemakes the bacterial cellwall permeable to the recombinant vectors. Inside the host cellthe recombinant DNA replicates.Host bacteria produce clones.Clone is genetically homogenous populationformed from a single cell.
4. Selection of the transformed host cells: Selection depends upon the nature of gene that is cloned.For antibiotic resistance, first the cells are incubated in antibiotic free medium.Antibiotic resistant genes will be expressed out. Then the clones are incubated in antibiotic medium. Clone containg the desired gene will be selected by clone hybridization by using probes. A Probe is a single stranded DNA or RNA segment radioactively labeled.Probe locates the complementary DNA sequence.
c DNA : DNA synthesized from mRNA by using reverse transcriptase enzyme is called c DNA.It is used as probe.
C DNA has practical applications: 1) c DNA can be directly cloned to detect gene of interest. 2) to diognise infectious diseases,food contamination 3) used in forensic tests including DNA fingerprinting.
Transgenic plants: Plants with desired characters created through genetic engineering methods are called Transgenic plants. Ti plasmid of Agrobacterium tumefaciens is widely used vector for obtaining the transgenic plants.These are obtained in monocots like wheat,rice,oats,maize, besides in many dicots.
Benefits of transgenic plants: 1) They are resistant to herbicides,insects and virus,increase fertility. 2) they are suitable for food processing ex:Bruise resistant and delayed ripening tomato plants. 3) Producton of male sterile plants in Brassica napus reduce the cost of hybrid seed production. 4) Using of Transgenic plants as bioreactors for specialized medicines,chemicals,antibiotics is called Molecular farming. 5) used to identify the regulatory sequences of many genes.

8. What is Hybridization ? Describe various types of Hybridization with suitable examples ?
It is the method of producing new crop varieties by crossing two genetically different parents.By Hybridization as many as desirable characters can be incorporated into a single variety.
There are three types in Hybridization:
1. Varietal hybridization: Two types: a) Intravarietal H: (within the variety) It is the cross between two plants of different genotypes, within the same variety. In Maize two inbred lines of the same variety are crossed. intervarietal: (intraspecific ) H: It is cross between two varieties of the same species.Jaya variety of Rice—T.N.1 x T.141;Padma variety nof rice—T 141 x T.N.1; Pusa variety of tomato—Sioux x Meeruti
2. Interspecific ( intrageneric ) H:Crossing two species of the same genus. Disease,drought resistance genes can be transferred from one species to another. P.I.94587 variety of wheat ( resistant to Hessian fly )-Triticum
--9--

aestivum x T.durumeviraj variety of cotton= Gossypium hirsutum x
G.arboreumevitej variety of cotton = Gossypium hirsutum x G
. herbaceum.;Red plum variety of Tomato = Lycopersicum esculentum x
L. pimpinellifolium.
3. Intergeneric H: crossing two genera of the same family.Difficult and rare method.First synthetic genus Raphanobrassica= Raphanus x Brassica of Fam;Brassicaceae.Useful synthetic genus Triticale of Poaceae= Triticum aestivum x Secale cereale.
-------------------------------------------------------------------------------------------

9. Explain briefly the steps involved in the tissue culture ?

The steps are:

1. Prepararion of nutrient culture medium: Popularly used medium is Murashige & Skoog medium.The nutrient medium without any growth regulaters is called basal medium. It is a mixture of variousessential micro and macro nutrients.,amino acids ,vitamins. Carbohydrates.They are mixed in distilled water.pH is adjusted to 5.6 to 6.The medium is solidified by adding agar-agar for providing support.Basal medium support seedling and callus growth.GrowthregulatorslikeIAA.NAA,2,4D,Gibberellins,Cytokinins,Kinetin,benzylamineregenerate plants from tissue culture.Basal medium is kept in glass vessels like culture tubes,flasks,,bottles and closed with nonabsorbent cottonplugs which allow exchange of Co2 and O2.

2. Sterilization of cuture medium: Sterilization is carried out in a autoclave for 15 minutes,at 121 C at 15 lb pressure.,to kill the contamination of microorganisms,in culture medium.Only the non contaminated medium is used for incubation of explants.

3. Preparation of explants: Any plant or plantpart used as inoculum in vitro is called explant.Explant is cleaned with liquid detergent in running water.For surface sterilization,sodium hypochloride solution is used.Seeds are sterilized with 0.1 mercuric chloride.,rinsed with distilled water.

4. Inoculation of explants: Inoculation is the transfer of explants onto the sterile nutrient medium,in culture vessels. It is carried out in Laminar airflow chamber in aseptic environment.

--10—

5. Incubation for growth: Culture are incubated for 3-4 weeks.The explant produces undifferentiated mass of cells callus,in culture medium with 2,4-D.Organogenesis is the production of shoot and root with combination of cytokinins and auxins respectively.Root generation with more auxin content is called rhizogenesis.Caulogenesis is the regeneration of shoot with more higher content of cytokinin.Thus a complete plant is regenerated.Production of embryogenic callus forms embryoids.The
embryoids developed from somatic cells are called somatic
embryos.These embryos are encapsulated in sodium alginate for
storage and transport and are called synthetic or artificial seed.

6. Acclimatization of plantlets and transfer to pots: The plants are gently
washed to remove culture media.Plnts are kept in pots containg soil-
rite ( coconut shell,organic matter ).Pots are covered in polythene bags
to provide high humidity.Within 1 or 2 weeks at room temperature
plants appear strong and healthy.Thua acclimatized plants are
transferred to regular pots containg mixture of soil and manure.
------------------------------------------------------------------------------------

.

Comments

1. Describe various types of Root modifications.
2. Describe any six stem modifications,helping in vegetative propagation.
3. What is Multipurpose stem modification ? Describe them with suitable examples.
4. Describe different types of aerial stem modifications.
5. Write about various types of sub-aerial stem modifications.
6. Describe various types of leaf modifications with examples.
7. Describe various types of Racemose inflorescence having pedicellate flowers.
8. Describe various types of Racemose inflorescence with sessile flowers.
9. With a neat labeled diagram ,describe embryo sac in angiosperms.
10. Briefly describe Fertilization processin angiosperms.
PLANT TAXONOMY:
1. Briefly describe Bentham & Hooker classification.
2. Describe the family:Malvaceae and its economic importance.
3. Describe vegetative and floral characters of Fabaceae .Give four examples with their economic importance.
4. Describe the floral characters and advanced features of of Asteraceae.
5. Write about the family Solanaceaeaned its economic importance.
6. Write the family features of Liliaceae with important plants and their economic importance.
INTERNAL MORPHOLOGY:
1. Describe the structure ,function of various types of meristems.
2. Describe the internal structure of Dicot root.
3. Describe the internal structure of Monocot root.
4. Describe the internal structure of Dicot stem.
5. Write the internal structure of Monocot stem.
6. Write the internal structure of Dorsiventral leaf.
7. Describe the internal structure of isobilateral leaf.
SECTION-B. Short Questions.4 marks.
1.Explain the organization and functions of B.S.I.
2. Enumerate the activities of research institute which conducts research on forests.
3. Name the international institute established to achieve food grain production.What are its functions.
4. Explain the activity and organization of the institute which is concerned with pharmacognostic studies.
5. What kind of efforts were carried out aiIARI to achieve agricultural development in India.
6. Enumerate the functions and achievements of NBRI.
7. Explain the contributions made by Prof.P.Maheswari.
8.What are the contributions of Dr.M.S.Swaminathan for achieving Green
revolution in India.

--2—

9. Name the scientist who got international fame in research on Rust
diseases.Give a brief account of his researches.
10.In which field of research is Prof.MOP Iyengar famous?Give an account of his
work.
11. Explain the contributions made by Prof.Birbal Sahni.
12.Define Phylloclade?Describe it.
13. Differenciate rhizome and corm.
14. Compare Phyllode and Phylloclade.
15.What is Heterophylly?Describe various types in it.
16. What is Venation ?explain various types in it.
17. Write short notes on single flower like special inflorescence.
18. Write short notes on a single fruit like inflorescence.
19. Describe the types of flowers classified on the basis of position of
gynoecium.
20. What is Heterostyly?How does it help in cross pollination.
21. Explain Dichogamy.
22. Write short note on Cleistogamy.
23. What are the three types of entry of pollen tube into the ovule.Give
examples.
24.Differenciate between true and false fruits.with examples.
25. Write short notes on aggregate fruits.
26. Write short notes on multiple fruits.
27. Write about the dry fruits which are single seeded.
28. Write short notes on capsules.
29. Write about the types of classification of flowering plants.
30. Explain binomial nomenclature.
31. Briefly describe the various Taxonomic units.
32. Explain the three aspects of Taxonomy.
33. write short notes on ICBN.
34. Differenciate between Ray and Disc florets.
35. Mention the advanced features of Asteraceae.
36. Write about the structure chemical nature and functions of cellwall.
37. Give an account of the cell organelle refered as Cell brain.
38. Give an account of the structure and function of the part of the cell refered as “physical basis of heredity.”.
39. Write the differences between DNA and RNA.
40. Give an accoumt of the organelle that causes autolysis of cell.
41. Write about the events of Pachytene and its significance.
42. Bring out the differences between Mitosis and Meiosis.
43. Which tissue secretes water? Describe its structure and mention two examplesof plants in which it is found.
44. Describe structure and function of cork tissue.
45. Describe the structure and function of lenticel
.
--3--
46. What are Hydrophytes?Briefly discuss different types of Hydrophytes with examples.
47. Enumarate morphological adaptations oh Hydrophytes.
48. List out the anatomical adaptations of Hydrophytes.
49. Write on classification of Xerophytes.
50. Write morphological adaptations of Xerophytes.
51. Describe anatomical adaptations of Xerophytes.
52. Compare Hydrophytes and Xerophytes.
SECTION- C. Very Short Answer Questions. 2 marks.
1. What is the name of the institute that studies the floristic distribution of our country ? Who was its founder.
Botanical Survey of India, Sir Joseph Dalton Hooker,
2. State why ICRISAT was established at Patanchervu near Hyderabad,.
Semi arid climatic conditions,black cotton and red cotton soils.
3. What is the most important finding of K.C.Mehta’s research.
Annual occurrence of rust in wheat and barleyis mainly due to the
Wind from hills that carry the infection to the plains.
4. Who discovered the technique of fertilization in a test tube.What
advantages did it have?
Prof.P.Maheswari.Explained the role of embryology in taxonomy.
5. What is the finding that brought international reputation to Prof.Birbal
Sahni.
Reconstruction of fossil gymnosperm group Pentoxylae.
6. What is meant by “Green Revolution”.Who achieved it in India.
Achieving self sufficiency in food production .M.S.Swaminathan.
7. Who is the Father of Green Revolution in India.How did he achieve it in India.
M.S.Swaminathan.Developing high yielding varieties in wheat
By using Mexican varieties.Introduced several varieties of Rice .
8. Who is the Father of Indian Palaeobotany.Name the place where the
institute of Palaeobotany was established.
Prof.Birbal Sahni.Lucknow.
9. How is M.S.Swaminathan responsible for achieving the economical
progress of our country.
By developing new varieties in commercial crops potato,jute
10. Define Root crops.What would happen if the root crops are harvested at
the end of second year.
As the roots store nutritive material ,they are called “root crops”.
They store food in roots in first year.Food is used up in the production
Of flowers,fruits and seeds in second year.They are not tuberous
With food,when harvested at the end of second year.
11. Where from the Bulbils arise in Dioscorea and Agave
In Dioscorea from axils of leaves,in Agave from axils of bracts
On the inflorescence

--4--

12.Name the special inflorescence which has a single female flower and many male
flowers.What are its cymose characters
Cyathium.Male flowers are arranged in Scorpiod cyme.in centrifugal manner.
13.What are the three types of styles?Give examples
Terminal-Ex.Hibiscus.Lateral-ex:Mangifera:Gynobasic-ex:Ocimum.
14. What are the two types of stamens classified depending on their length
Didynamous:Out of 4,two are long and two are short.Ex:Ocimum.
Tetradynamous:Out of 6 in two whorls,two in outer whorl are shorter
And 4 in inner whorl are longer.ex:Brassica.
15. What are the cells found in the egg apparatusof a mature embryo sac
The middle bigger egg cell,surrounded by two synergids one on either side with finger like projections filiform apparatus helping in absorption and conduction of food.
16..Define di and tri heterostyly with examples
Diheterostyly:arrangement of styles in two different heights in dimorphic
Flowers of the same species.Exrimula.
Triheterostyly:arrangement of styles and stamens in three different lengths
(short,medium and long).ex:Oxalis.
17. Define protandry and protogyny.
Protandry:Maturation of antheridium earlier than gynoecium,in bisexual flower.ex:Helianthus.
Protogyny:Maturation of gynoecium earlier than androecium in bisexual flower.ex:Solanum.
18. What is the main difference between cleistogamy and chasmogamy.
Cleistogamyollination occurring in unopened flowers.ex:Commelina.
Chasmogamyollination occurring in opened flowers.
19. What is syngamy?Who first discovered it.
Fusion of sperm nucleus with the egg cell forming a diploid zygote
Is called syngamy.Strasburger discovered syngamy.
20.What is triple fusion?Who first described the process of triple fusion.
Fusion of haploid sperm nucleus with diploid secondary nucleus forming
Triploid primary endosperm nucleus.(PEN).Nawaschin discovered it.
21.If there are 16 chromosomes in the cell of an angiospermic plant,how many
chromosomes are there in the perisperm and endosperm cell?Explain
Perisperm-haploid-8:endosperm-triploid-24.
22.Why are apple and cashewnut called false fruits.
In apple thalamus,in cashewnut pedicel form edible with food stored.
23.What are the single seeded dry fruits you have studied.
Dry indehiscent-achene,caryopsis,cypsela,nut and samara.
24.What is Tautonomy.Give an example.
Generic name and species name are exactly same.ex:Malus malus.
25.What is Binomial nomenclature.Who introduced this system.
A plant having generic name followed by species name in Latin.
Gaspard Bauhin.
--5—
26.What is ICBN? What is its role in Taxonomy.
International Code of Botanical Nomenclature.In accordance with its
Principles naming of plants should be done.
27.What is the difference between Alpha taxonomy and Omega taxonomy
Alpha taxonomy:taxonomy purely based on the description of
Morphological characters.
Omega Taxonomy: apart from morphology,importance is given to
phylogeny also.
28. What is sexual system of classification?Who introduced this.
Classification in which floral characters are given importance.Linnaeus.
29. Who was the author of Genera Plantarum?Why is the classification given
in this called a natural system.
Bentham and Hooker.considering all possible morphological characters
Plants are grouped on their natural relationships.
30.Who was the author of “Flora of British India”.What is the use of these
books.
J.D.Hooker.Helps in identifying the flora in British India.
31. What is the basic unit of classification?Define it.
Species.Plants identical in all respects are regarded as one species.
32. What is epicalyx?Give the Scientific name of one plant in which it is present.
Whorl of bracteoles outside the calyx. Hibiscus rosa-sinensis.
33. To which family do pulses belong?Give two examples with scientific names.
Fabaceae.Dolichs lab lab:Cajanus cajan.
34.Name the pigment present in root nodules of Fabaceae.
Leg-haemoglobin.
35. From which plant chicory is obtained and to which family does it belong.
Cichorium intybus. Asteraceae.
36. How pollination will occur in Helianthus when it is grown in an insect free
environment.
Safety mechanism:stigmas bend back and get self pollinated
37. From which plant is Colchicine obtained.and what is its use.
Colchicum autumnale.chemical mutagen “colchicine”
38. To which family does Yucca belong.Name the moth that is associated with
the pollination in Yucca.
Liliaceae.Pronuba yuccasella.
39. What is the botanical name of Great Millet?To which family does it belong.
Sorghum vulgare. Poaceae.
40. How is Gun cotton prepared.What is its use.
By treating celluslose cotton with conc.Nitric acid.Gun cotton is used in
Making gun powder and explosives.
41. What is the botanical name of “The Pride Fruit of India”.What is the nature
of fruit.
Mangifera indica. Drupe with juicy edible mesocarp.
42. Give the botanical name,family and useful part of mango
Mangifera indica. Anacardiaceae.rpicarp and jucicy edible mesocarp.
--6—

43. What is the botanical name of “Herbal Indian Doctor.”To which family
does it belong.
Azadirachta indica. Meliaceae.
44. Neem is regarded as “Herbal Indian Doctor”.Elaborate.
Everypart of the plant is useful.
45. Differentiate between purine and pyrimidine.
Purine:heterocyclic compounds having two C-N rings.
Pyrimidine: homocyclic compounds having one C-N ring.
46. Differentiate between nucleoside and nucleotide,
Nucleoside:the association of sugarmolecule and a base.
Nucleotide:Association of phosphate group,sugar and a base.
47. How do you identify heterochromatin and euchromatin.
Heterochromatin:genetically inactive dark stained region of chromosome.
Euchromatin:lightly stained,genetically active region of chromosome.
48. Why mitochondria are called “power houses of cell”.
Energy is stored as ATP in matrix.
49. Why chloroplasts and mitochondria are called semi autonomous cell
organelles.
Self duplicating with own genetic material.
50. Who proposed cell theory?What are its main contents.
Schwann.Cell is structural and functional unit of an organism.
51. Mention three types of leucoplasts and the kind of food material
stored in them
amyloplasts store starch;aleuroplasts store proteins;elaioplasts store
fats and oils.
52. Differentiate between B-DNA and Z-DNA.
B-DNA=more common,clockwise helix structure.with hereditary stability
Z-DNA=uncommon,alternate,zigzag,helix,with no hereditary stability.
53. In a cell haploid chromosome number is 15.What number is found
in pollen grain,zygote,primary endospermnucleus,and colchcine treated zygote.
Pollen grain:15;zygote:30;PEN;45;colchicine treated zygote:60.
54. “Genetic recombinations occur only in meiosis but not in mitosis”why.
Chiasmata leads to exchange of genetic material resulting in
Recombination of genetic characters.
55. . What is the most suitable stage for observing chromosomes in a microscope.?why.
Metaphase.Chromosomes are oriented in systematic manner in equator.
56. If crossing over fails to occur ,what change is observed in the daughter cells.
Daughter cells will have the same homologous chromosomes.
57. What is guttation.
Exudation of water in the form of droplets through Hydathodes,from leaf margins,apices.
--7—

58. What are bulliform cells?What is their role.
Enlarged specialized cells in upper epidermis of monocot leaf.
They help in rolling and unrolling of leaf.
59.Define population and community.
Population:Group of similar individuals of the same species in an area.
Community:assemblage of all populations of different species in an area.
60. Name two amphibious plants?
Limnophila,Cyperus,Typha,Ranunculus.
61.What are hydrophytes.Which type of tissue is responsible for bouyancy
in hydrophytes.
Plants growing in water and in very wet places.aerenchyma.
62. Which aerial stem modification is concerned with vegetative propagation?
Explain.
Offsets in Pistia,Eichhornia,fragmentation in Hydrilla.
63. Name the sub aerial stem modification found in free floating aquatic
plants.How does it help in vegetative propagation.
Offset.Reduced internodes elongate producing daughter plants.
64. What are the tendrillar structuresfound in Smilax,Pisum,Clematis
and Gloriosa.
Stipules in Smilax,terminal leaf-lets in Pisum,petiole in Clematis,
Leaf tip in Gloriosa.
65. Define leaf-mosaic type of phyllotaxy.Give an example.
Special type of alternate phyllotaxy.lower older leaves have longer petioles
And upper younger leaves have shorter petioles.upper younger leaves lie
In the spaces present in between the older leaves. Ex:Acalypha indica.
66.Compare homogamous head and heterogamous head inflorescence.
Homogamous head:head with one kind florets
Ex: Vernonia(disc),Tagetus(ray)
Heterogamous head:with ray florets at periphery and discflorets at center
Ex:Tridax,Helianthus.
67.Define monoecious and dioecious condition.
Monoecious:male and female flowers on the same plant.ex:Cocos nucifera.
Dioecious:male and female flowers are on separate plants.ex:Borassus,
68. What is the difference between adelphous and syngenesious condition
adelphous:filaments united,anthers free.
Syngenesious:filaments free,anthers united.exisc floret of Tridax..
69. What is cleistogamy?What is its advantage.
Pollination in unopened flowers.It favours self pollination.
70. Compare the endosperm of angiosperms with that of gymnosperms.
Triploid,post fertilized in angiosperms,haploid,prefertilized in
Gymnosperms.
71. What is endosperm?What is its use.
Nutritive tissue formed from primary endosperm nucleus after
Fertilization.It nourishes the developing embryo.
--8—

72. Write a brief note on perisperm.
The left out nucellus in the seed .exiper nigrum.
73. Name two types of special appendages developed outside the seed.
Give examples.
Aril:integument like out growth developed from funicle of a fertilized
Ovule.exithecalobium dulce.
Caruncle:sponge like outgrowtharising from the integumentary cells at
Mycropylar region.ex:Ricinus communis.
74. What is ICBN ? What is its role in Taxonomy
International Code of Botanical Nomenclature.According to its principles
Plants are classified..
75. What do we call all those done after the announcement of Darwin’s
theory and what is their principle character.
Post-Darwinian classifications.evolutionary and phylogenetic relations
Among plants.
76. What is geocarpy?Give an example where geocarpy is seen.
Development of fruit inside the soil.ex:Arachis hypogea.
77. What is the nature of calyx in Asteraceae and what is its use
persistent and pappus.Help in fruit dispersal. .
78. Name the insecticide obtained from Chrysanthemum cinerariaefolium
From which part of the plant it is obtained.
Pyrethrum.From flowers.
79. Name the alkaloid obtained from Atropa belladonna.What is its use
atropine.useful in making plasters..
80. Write the characters of gynoecium in Solanaceae
Bicarpellary syncarpous,obliquely zygomorphic due to rotated.
Anterior Carpel at 45 degrees angle to the left.
81. What is the scientific name of the monocot plant with reticulate
venation. Which family does it belong.
Smilax.Liliaceae.
82. To which family do pulses belong. Give two examples with scientific
names.
Fabaceae. Dolichos lab lab,Cajanus cajan.
83. What is the botanical name of cotton.Which acid is used along with
cotton to make explosives.
Gossypium herbaceum. Conc.Nitric acid.
84. What are lint and fuzz.
Lint:long epidermal hairs of cotton seeds.
Fuzz:short epidermal hairs of cotton seeds.
85. Which plant produces oil having insecticidal property and useful to control
skin diseases.Give its botanical name.
Neem. Azadirachta indica.

--9—

86. Differentiate between autosomes and allosomes.
Autosomes:somatic,vegetative chromosomes more in number.
Allosomes:sex chromosomes in germ cells. X,Y,in human beings.
87. Differentiate between prokaryotic cell and eukaryotic cell.
Prokaryotic cell:cell with illdefined nucleus.called nucleid.
Eukaryotic cell:cell with well defined nucleus.
88. Who wrote the book Micrographia.What does this book explain about
Robert Hooke..cells as compartment like hollow spaces.
89. Differentiate between autocatalysis and heterocatalysis functions of DNA
Autocatalysis:duplication of single DNAmolecule into two daughter
molecules.
Heterocatalysis:transcription of DNA into mRNA .
90. The sequence of nitrogen bases in one strand of DNA is GCT,ATG,CCA,
TGC.What is the sequence present on the opposite strand .What is the
Relationship known as.
CGA,TAC,GGT,ACG.complimentarity.
91. What difference can be observed in the metaphases of meiosis I and
meiosis II
MeiosisI:centromeres towards poles,arms towards equator.
MeiosisII:centromere at equator,arms towards poles.
92. What is crossing over .What is its significance.
The process of exchange of genetic material between the non sister
Chromatids resulting in recombination.It results to origin of new
Species and evolution.
93. Differentiate between angular collenchyma and lamellar collenchyma.
Angular collenchyma:cells are not arranged in regular rows.The
Cell wall deposition is in the cell corners.Intercelular spaces are absent
Lamellar collenchyma:cells are irregularly arranged with small
intercellular spaces.cell walls are thickened around the intercellular
spaces.
94. Differentiate between libriform fibres and fibre-tracheids.
Libriform fibre:True xylem fibres with simple pits in the walls.
Fibre tracheid:nonfunctional tracheids with bordered pits in the walls.
95. What are Tyloses?What is their importance.
Balloon like structures from xylem parenchyma developing into
Adjacent vessels.They check the spread of the pathogen.
96. What are casparian thickenings.
Lignin and suberin depositions on the radial and transverse walls
Of endodermal cells.
97. State why annual rings are not formed in the trees of tropical zones.
Seasonal variations are not sharp in tropical zones.
98. What are pseudo-annual rings?Why are they formed.
Annual rings formed due to hormonal changes or heavy leaf fall or due to
Disease.
--10--

99. Heart wood is considered more durable than sap wood. Why
Heart wood is hard and more durable due to the storage of
oils,gums,resins,tannins etc..
100. Name two freefloating hydrophytes having balancing roots
Pistia,Eichhornia..

Comments

1. Tuberous or storage roots: Due to storage of food ,roots become bulged.,changed in shape. Due to storage tap roots are spindle shaped in Raphanus sativus,Conical in Daucus carota,Napiform in Beta vulgaris. These roots store nutritive materials and are called root crops. These plants are called Biennials growing for two years or two seasons. Plants prepare and store food in the tap roots at the end of first year and utilize the food in the second year producing flowers and fruits. Root crops should be harvested at the end of first year only. In Ipomoea batat a single tuberous root,in Asperagus a cluster of tuberous roots are found. In Beta vulgaris food is in the form of sugar, in Dahlia in the form of Inulin, in all others in the form of starch.

2. Epiphytic (or) Velamen Roots: The plants taking shelter on the branches of other tall trees for more sunlight are called Epiphytes. They have two types of roots,a)branched short clinging roots fix epiphyte on the branch of host plant. long brown branched freely hanging Velamen roots absorb moisture from atmosphere.These roots contain dead hygroscopic epidermal tissue called Velemen.Epiphytes show xerophytic features as they do not get continuous water supply. Ex: Vanda.

3. Photosynthetic (or) assimilatory roots: In epiphyte Taeniophyllum,stem,leaves are absent.Roots are aerial,flattened,green,synthesizing food and are called assimilatory roots.In Tinospora,aerial roots,in Trapasubmerged roots are green with chloroplasts.

4. Pneumatophores (or) respiratory roots: Mangroves growing in saline,marshy,water logged soils do not get oxygen for root respiration from soil. Some special aerial branches from roots form respiratory roots Pneumatophores with small pores Pneumathodes for gaseous exchange.ex:Rhizophora, Avicennia.In free floating hydrophytes Jussia,breathing roots are spongy,

5. Parasitic roots(or) haustoria: Plants depending on other plants completely or incompletely are called Parasites.Special adventitious rootsproduced by parasites to get food and nutrientsfrom host plant are called Haustoria.
Parasites are a)stem parasites(on host stem) are complete parasites ex:Cuscuta,and in- complete parasites ex:Viscum.b) root parasites (on host root ) are complete root parasites ex:Orobanche and in-complete root parasite ex:Striga.Leaf less ,nonchlorophyllous parasites getfood and mineral water from the host plant by establishing haustoria with both phloem and xylemforming complete parasites.In-complete parasites have green leaves,establishing haustoria with xylem of host plant to get mineral water only.

-2-
AERIAL STEM MODIFICATIONS.

When the entire or a part of the aerial stem changes into a permanet structure to carry another function in changed environment it is called aerial stem modification.

1. Tendrils: Tendril is delicate wiry coiled sensitive organ useful for climbing.Tendril coils around the supporton contact.In Passiflora axillary buds, in Vitis terminal buds develop into tendrils

2. Thorns: Hard woody pointed vascularised structure meant for protection is called thorn.In Bougainvilla axillary bud,in Carissa terminal bud (into a pair of thorns) modifies.In Duranta axillary bud develops into thorn bearing leaves and flowers.In Punica granatum axillary bud develops into thorn bearing leaves and branches.

3. Hooks: Sensitive curved woody structure helping in climbing is called hook.Axillary bud forms hook inHugonia.In Artabotrys terminal bud forms inflorescence whose peduncle curves forming hook.

4. Phylloclade: Leaf-like stem is called Phylloclade.It is a xerophytic feature.To reduce transpiration leaves modify into spines,stem becomes green with chlorophyll forming Phylloclade.In Opuntia leaves of axillary bud form a group of spines some may be small hair like barbs. Group of spines and barbs at each node represent areole.Flattened short green or cylindrical branches of limited growth are called Cladophylls or Cladodes.They are cylindrical ,one internode length formed from axils of leaves in Asparagus.In Ruscus they are flat leaflike formed from axils of scale leaf. Chladophyll bears male or female flowers at node on the surface.

5. Tuberous stems: Aerial stem becomes tuberous due to storage of food material.In Bulbophyllum an epiphyte, one basal internode forms Pseudobulb due to storage of food.In Brassica oleracea var gangyloides (knoll-khol) entire stem becomes tuberous due to storage of food.

6. Bulbils: The modified condensed branches with stored food helping in vegetative propagation are called Bulbils.In Dioscorea bulbifera bulbils form from the axils of bracts.In Oxalis a group mof bulbils develop from the top of tuberous root.

-3-

SUB-AERIAL STEM MODIFICATIONS.

These are weak stemmed plants. Stems are partly aerial and partly underground.
These are 4 types.

1. Runners; ex:Oxalis; Lippia; Stem creeps on the soil rooted at every node. Nodes can grow into independent plants (vegetative propagation),when the internodes break off.

2. Stolons;ex:Nerium,Jasminum. These are basal long branches growing obliquely ,producing adventitious roots when touch the soil.These stolons can become independent plants when separated from the main plant.(layering process)

3. Suckers: ex:Mentha;Chrysanthemum. These are obliquely growing underground
Branches of the stem.These suckers with adventitious roots below.can become independent,when separated.

4. Offsets: existia;Eichhornia.In these free floating hydrophytes,stem is very much reduced,leaves form in rosette.Axillary buds develop into short slender branches of one internode length called Offsets.From the tip of the offset leaves form above,roots below.Offsets become independent plants when they are cut from the main plant.Agave Americana terrestrial land plant produces offsets.

UNDERGROUND STEM MODIFICATIONS

These are stems growing inside the soil.They are fleshy swollen,due to food storage.They are protected from herbivorous animals.They help in vegetative propagation and perennation.So these are also called multipurpose stem modifications.These are:

1. Rhizome:ex:Zingiber officinalis,Canna indica. Horizontally growing underground stem is called Rhizome.It has nodes,internodes,scale leaves at nodes,adventitious roots below.shoots above.Rhizome perennates even in drought.

2. Corm: ex:Colacasia; Amorphophalus. Vertically growing underground stem at particular depth is called Corm.It is tuberous with nodes,internodes,scale leaves.
Axillary buds form daughter corms.Apical bud forms aerial shoot.The special adventitious roots keeping the corm at particular depth in Amorphophalus are called Pull roots or contractile roots.

3. Stem tuber: Ex;Solanum tuberosum.The tips of the underground branches become
tuberous due to storage of food are called Stem tubers.It has outer brown coloured
periderm,eyes.Each eye-like structure has semilunar leaf scar with axillary bud
representing node.It helps in vegetative propagation.Stem tuber has no roots.The
stored food is starch in Solanum tuberosum, inulin in Helianthus tuberosus, Stachyose
in Stachys tubifera.
-4-

4. Bulb: Special type.Stem is reduced to biconvex disc,with roots belowleaves above the soil.Leaf bases become fleshy with food and water.Terminal bud grows into aerial
inflorscence,axillary buds produce daughter bulbs,helping in vegetative propagation.
Bulb is only the underground stem that does not store food in stem.Based on the
arrangement of scale leaves bulbs are two types.

a) Tunicated bulb: ex:Allium cepa.Fleshy leaf bases overlap in concentric rings,circles.Entire bulb is covered by dry membrane called tunic.

b) Scaly bulb: Allium sativum.Imbricate or naked bulb.Individual scale leaves become fleshy due to storage of food.They are loosely arranged as in Lilium candidum and fleshy cloves are enclosed by whitish skinny dry tunic as in Allium sativum.
-------------------------------------------------------------------------------------------------

LEAF MODIFICATIONS

If the entire leaf or a part of it undergoes permanent change to perform new
function suitable for the environment it is called leaf modification.They are:

1. Tendrils: Weak stemed plants climb up the support by delicate wiry tendrils.In Lathyrus entire leaf except stipules,in Pisum terminal leaf lets of compound leaf,in Smilax stipules, in Nepenthes part of petiole, in Clematis petiole modify into tendril.

2. Spines: Sharp pointed structures.Xerrophytic character.Spines reduce the rate of transpiration.They protect the plants from herbivorous animals.In Asparagus entire leaf, in Phoenix leaf tip, in Acacia stipules , in Argemone leaf margin,in Citrus first leaf of axillary bud modify into spines.

3. Scale leaves:Thin small colourless,dry membranous,structures are called scales.In Casuarina phylloclade scales reduce transpiration.In Zingiber underground stem scale leaves protect axillary and terminal buds . In Allium scaleleaves store food.

4. Phyllode:green flattened photosynthetic petiole or secondary rachis is called Phyllode.In Acacia melanoxylon,petiole of the pinnately compound leaf modifies into phyllode.In Parkinsonia primary rachis ,stipulesmodify into spines.Secondary rachis forms phyllode,with small deciduous leaflets.

5. Reproductive leaves:Leaves with epiphyllous buds are called reproductive leaves.They help in vegetative propagation.In Bryophyllum epiphyllous buds lie in the notches of crenate leaf margin.In Scilla indica leaf tip bears bud.,that grows into new plant when the leaf tip touches the soil.In Begonia injured parts of leaf produce buds.

-5-

6. Trap leaves,insectivorous leaves,carnivorous leaves:These plants grow in Nitrogen deficit soils .Leaves are used as traps to catch and kill the insects to get nitrogen in the form of proteins.Insect proteins are digested and assimilated into the
plant .Insectivorous plants secrete digestive juices in leaves.ex: Drosera, Dionaea,
Utricularia, Nepenthes.

Mechanism in Nepenthes: It is called Pitcher plant.Lower part of petiole is wing like, upper part forms tendril. Leaf lamina forms pitcher .Leaf tip forms lid.Lid is immovable colourful,attractive.Rim of Pitcher is slippary ,lined with digestive
glands and downwardly projected hairs into pitcher.Insect is attracted by lid and nectar.When the insect lands on rim it slips down and drowned in acidic fluid in pitcher.Downwardly projected hairs prevent the insect escape .Insect is killed and digestedby proteolytic enzymes.Nitrogenous substances are absorbed and transported.

RACEMOSE TYPE INFLORESCENCE

Peduncle grows indefinitely. Flowers are arranged in acropetal manner ie.older flowers are at bottom younger ones are at the top. When the peduncle is reduced opening of flowers is centripetal ie. From periphery to center. Two types:

A) Racemose type with pedicellate flowers:

1. Simple Raceme: ex: Crotalaria. Bracteate pedicellate,flowers are arranged in acropetal manner,on indefinitely growing peduncle.
Compound Raceme: Mangifera, Yucca. It is also called Panicle.Peduncle is branched. Each branch resembles a simple raceme.

2. Simple Corymb;ex: Cassia; Gynandropsis.It is like a simple raceme.
But all the flowers are brought to the same level,height. Lower flowers have long pedicels and upper ones have shorter pedicels.
Compound Corymb; ex: Pyrus malus; Brassica oleratia var. botrytis.
Peduncle is branched .Each branch is a simple corymb.In Cauliflower peduncle is fleshy storing food.

3. Simple Umbel : ex: Allium cepa.Many pedicellate bracteate flowers
arise as a cluster at the apex of unbranched condenced peduncle.All the
bracts unite to form whorl called “ involucre”. Flowers open in
centrifugal manner.
Compound Umbel : ex: Coriandrum sativum., Daucus carota. Peduncle

-6-
is branched. Each branch bears a simple umbel.All the branches arise in umbel manner .Involucre of bracts occur at the base of branches.Involucel of bracteoles occur at the base of simple umbels.
Racemose type with sessile flowers:

1. Simple Spike: ex:Achrynthes, Amaranthus. Bracteate sessile flowers arise acropetally on unbranched peduncle.Similar to simple raceme but for the sessile flowers.
Compound spike .( spike-let) ex: Oryza; Triticum. Peduncle is branched.It grows indefinitely.Each branch produces bracteate sessile flowers acropetally.Each branch is a spike-let. Its axis is called Rachilla.Bracts are glumes.Basal glumes without flowers are sterile .Fertile glumes are with flowers.Bracts form lemma, bracteoles form palea,the reduced perianth form lodicules. Characteristic in familyoaceae.

2. Catkin : ex : Casurina ; Acalypha. It is spike like.Peduncle is
long.weak,drooping. Many sessile,unisexual flowers arise on peduncle
in acropetal manner. Often called “ Amentum “ as is found in
Amentiferae.

3. Simple Spadix ;ex: Colocasia. Peducle is fleshy unbranched.The terminal flowerless part is called Appendix.Sessile unisexual flowers are below the appendix,female flowers below and male flowers above, neutral flowers in between.All the bracts unite to form thick leathery Spathe,covering the entire inflorescence.Common in Family.Aroideae.
Compound spadix: ex:Cocos nucifera. Peduncle is branched . On each branch arise unisexual female flowers below,male flowers above in acropetal manner.In Cocos spathe is hard woody boatlike,.In Musa each branch is covered by leathery spathe.

4. Head (or ) Capitulum ( or ) Anthodium : Highly evolved in Racemose
type.Seen in Asteraceae.Peduncle forms a flattened disc called
receptacle.Small sessile flowers are centripetally arranged on this.
Bracts form involucre around the inflorescence.Flowers are two types:
A) Disc flowers: actinomorphic,bisexual,central in position. Ray
flowers : zygomorphic,unisexual female,periphery in position.Based on the types of flowers present ,head may be Homogamous with only one kind of flowers.exnly disc flowers in Vernonia,only ray flowers in Tagetus.Heterogamous Head has both Ray flowers in margin and Disc flowers at center,ex: Tridax,Helianthus
Compound Head :Ex: Echinops; Sphaeranthus. Axis is branched.Each branch ends in Head inflorescence.
-7-

CYMOSE (OR ) DEFINITE INFLORESCENCE.

Flower develops at the ip of the peduncle.Its growth is definite.From the axils of bracts below this terminal flower,branches develop,which also end in flowers.Flowers arrangement is basipetal.ie first formed older flower is at apex,the later formed younger flowers at below.On the condenced axis opening of flowers is centrifugal ie. From center to periphery.

Cymose types are:

1. Solitary Cyme: Simplest type.Axis ends in a flower.Flower is axillary in Hibiscus,terminal in Datura.The articulation between the peduncle and pediceldistinguishes the nature.

2. Simple Cyme: A three flowered inflorescence.Axis ends in a flower.Below this two lateral flowers develop,in basipatal manner.ex:Jasminum, Bougainvillea.

3. Monochasial cyme: Only one branch develops below,when axis ends in a flower.The same nature repeats.Single branches unite forming Sympodial axis,looking like Racemose.In this flowers are not axillary. They are bracts opposed.They are two types on the nature of branches arranged.a) Helicoid:ex:Hamelia. Succesive lateral branches develop on one side,in spiral manner. Scorpioid:ex:Solanum.successive lateral branchesgrow on either side,in zig-zag manner.

4. Dichasial cyme:ex: Ipomoea.Two lateral branches develop below ,when axis ends in terminal flower. Inturn each lateral branch ends in a flower repeating the same process. This is called Dichasial as two branches develop at each time.(Clerodendron).

5. Polychasial Cyme: ex: Nerium.Axis ends in flower . Many lateral branches develop below.Each ends in flower.This nature continues.It is called Polychasial,since more than two lateral branches develop.

SIMPLE FRUITS.

Fruit developing from syncarpous gynoecium of a single flower is called simple fruit.On the nature of pericarp,simple fruits may be :
FLESHY FRUITS: Pericarp is fleshy,at the time of ripening.Separable into outer epicarp,middle mesocarp and inner endocarp.Seeds are liberated out when pericarp decays.
1. Berry: Fruit develops from bicarpellary or multicarpellary syncarpous gynoecium.Pericarp is separated into outer thin epicarp;middle mesocarp and inner endocarp fuse to form pulp with numerous seeds.ex: Solanum melongena.In Musa
berry is developed from inferior ovary.In Phoenix dactilifera single seeded berry
develops.
-8-

2. Pome:ex: Pyrus malus.Fruit is developed from bicarpellary or multicarpellary gynoecium,inferior ovary. Fleshy thalamus around the gynoecium is fleshy.Pericarp is hard enclosing the seeds.
3. Pepo:ex: Cucumis. Fruit is developed from uni or tricarpellary syncarpous gynoecium,inferior ovary.Pericarp is divided into outer epicarp fused with hard thalamus forming rind,fleshy mesocarp,smooth endocarp.Seeds are developed from the inner walls of pericarp.
4. Hesperidium:ex:Citrus species. (Rutaceae) Fruit is developed from multicarpellary syncarpous multilocular superior ovary. Pericarp is divided into outer leathery glandular epicarp,white papery mesocarp,many chambered inner endocarp with juicy edible hairs.Seeds on central axis.
5. Drupe:ex Cocos nucifera;Mangifera indica. Fruit develops from uni or multicarpellary superior ovary,unilocular,one seeded,with stony endocarp.In Mangifera,epicarp is leathery,mesocarp is fleshy,juicy,edible,endocarp is stony.In Cocos,epicarp is leathery,mesocarp is fibrous,endocarp is hard stony.Endosperm of seed (copra)forms edible part.

DRY FRUITS.: Pericarp is dry, undifferenciated when ripe.
DRY DEHISCENT FRUITS.
Pericarp breakes liberating seeds at maturity.They are:
1. Follicle:ex:Calotropis.Develops from superior ovary.Dehisces along one suture only.
2. Legume:exolichos.Develops from monocarpellary unilocular half superior ovary.Fruit breaks dorsiventrally into two halves liberating the seeds.
3. Siliqua:ex:Brassica.Developed from bicarpellary syncarpous unilocular ovary but made bilocular by false septum called replum.Seeds are on either side of replum.Pericarp breakes dorsiventrally from base to apex leaving seeds on replum.
4. Silicula;Ex:Capsella bursa pastoris.Short broad siliqua with limited number of seeds.
5. Capsule: Developed from uni or multicarpellary mulilocular superior ovary.
.Based on dehiscence, capsule may be:
a) Septicidal capsule:ex:Aristolochia.Capsule breaks along the septae,in between
locules,leaving seeds within the valves
b) Loculicidal Capsule:ex : Abelmoschus esculentus.Capsule dehisces through the middle portions of locules.Number of pieces are equal to the number of carpels.
c) Septifragal Capsule:ex: Datura. Pericarp dehisces either by loculicidal or septicidal leaving seeds on swollen axis of placenta,at the center.
d) Porous Capsule:ex: Papaver.Fruit is cup like with lid.Many pores in between on margin.Seeds are dispersed through the pores present on upperside..In Campanula from inferior ovary with pores at base.
e) Pyxidium:exortulaca.Spherical shaped capsule developed from superior ovary.Pericarp splits transversly.Upper lid falls off leaving seeds on basal cup like structure.

-9-

DRY INDEHISCENT FRUITS

One seeded. Never break even at maturity.Seed is liberated only after the decay of the pericarp.These fruits are:

1. Achene: ex:Clematis. Developed from monocarpellary unilocular superior ovary.Pericarp and seed coat are well separated.

2. Caryopsis:ex: Oryza. Pericarp and seed coat are fused together.

3. Cypsela: ex: Tridax. Developed from bicarpellary syncarpous unilocular inferior ovary.Persistant calyx form pappus helping in fruit dispersal.

4. Nut: ex: Anacardium.Developed from Bi or multicarpellary syncarpous unilocular superior ovary.Pericarp and seed coat are free,separated.Pericarp is hard,stony.

5. Samara: ex: Winged fruits.Developed from bi or tricarpellary syncarpous superior ovary.Wings develop from pericarp in Hiptage,from caly in Gyrocarpus,from style in Ventilago,from calyx and style in Shorea.

SCHIZOCARPIC FRUITS.
Fruit breaks into many single seeded bits called mericarps.Fruit shows both dehiscent and indehiscent features like breakage of pericarp,degeneration of pericarp to liberate seeds.Various types are:
1. Lomentum: ex: Acacia; Mimosa. Developed from monocarpellary gynoecium. Fruit is constricted inbetween the seeds,into which fruit breaks at maturity.Common in Mimosae.

2. Schizocarp:ex: Abutilon; Sida.Developed from multicarpellary syncarpous multilocular superior ovary.Fruit breaks into many mericarps.Each mericarp may have one seed ( Sida) or many seeds ( Abutilon ).Common in Malavaceae.

3. Carcerulus:ex: Ocimum. Developed from bicarpellary syncarpous tetralocular ovary.Fruit breaka into four nutlets.Each mericarp has stony pericarp.

4. Regma:ex: Ricinus. Developed from tricarpellery syncarpoustrilocular superior ovary. At maturity fruit breaks into three cocci,one seeded mericarps.

5. Cremocarp:ex: Coriandrum. Developed from bicarpellary syncarpous bilocular inferior ovary.At maturity fruit breaks into two one seeded maricarps attached to carpophore,an elongated thalamus.Common in Apiaceae( Umbelliferae ).

6. Double Samara:ex:Acer. Developed from bicarpellary syncarpous superior ovary.Fruit breaks into two samara like mericarps.
-10-

TAXONOMY
MALVACEAE

Examples: Systematic Position:
Abelmoschus esculentus ( benda) Class: Dicotyledonae.
Gossypium herbaceum (patti) Sub.Class: Polypetalae.
Hibiscus rosasinensis. (mandara ) Series: Thalamiflorae.
Hibiscus cannabinus (gongura ) Order: Malvales.
Thespesia populnea ( gangaravi ) Family: Malvaceae.

Vegetative Characters:mesophytes,mostlt herbs or shrubs,a few are trees (Thespesia ),
Vegetative parts are covered by stellate hairs,plant tissue contain mucilage cavities,mostly simple leaf (Hibiscus),palmately lobed ( Gossypium ),reticulate venation.

Floral characters:
Inflorescence:Solitary cyme,axillary in Hibiscus,terminal in Gossypium
Flower: large showy bracteate,bracteolate,3-10 bracteoles form a whorl called
Epicalyxoutsidecalyx,epicalyxisabsentinSida,Abutilon,bisexual,pentamerous,hypogynousCalyx: 5,gamosepalous,valvate.
Corolla: 5,polypetalous,twisted,fuse at base with staminal tube.
Androecium: numerous,epipetalous,monadelphous in Hibiscus,form staminal tube around style,anthers monothecous,reniform,extrorse,trnsverse dehiscence,large apherical pollen,with spinous exine.
Gynoecium: 5,in Hibiscus,syncarpous,ovary superior,number of locules equal to number of carpels,ovules on axile placentation,simple terminal style,stigma lobes equal to number of carpels in Hibiscus.
Floral Formula: Br,Epik3-10,+,o+’,K(5),C5,~A(&),G(3-&)
Pollination: cross pollination is due to protandry,flowers entamophilous.
Fruit: loculicidal capsule in cotton,schizocarp in Abutilon,berry in Malvaviscus.
Seed: nonendospermic,seedcoat has hairy outgrowths (cotton).

Economic importance:
1. fibre yielding,leafy vegetable-Hibiscua cannabinus.
2. Vegetable-Abelmoschus esculentus
3.cotton sps.-cotton yielding,cotton seed oil in soap making,oil cake as
cattle feed.
4. medicinal plants-Abutilon,Sida.
Important characters:1)stellate hairs on vegetative plant parts,with mucilage within tissues,2)epicalyx, 3)stamens=numerous monadelphous,staminal tube,anthers monothecous,reniform.4) superior ovary,number of carpels equal to number of locules in ovary,axile placentation, 5) fruit=capsule.
----------------------------------------------------------------------------------------------------------------.
.
-11-
FABACEAE.(sub.fam. Papilionaceae of fam.Leguminaceae.)
Examples: Sys.Position:Cla: Dicotyledonae.
Arachis hypogea (verusenaga ) Sub.Clasolypetalae.
Cajanus cajan (kandulu ) Series: Calyciflorae.
Cicer arietinum (sanaga) Ord: Rosales.
Dolichos lab lab (chikkudu ) Fam: Fabaceae.
Glycine max (soya bean )
Phaseolus mungo (minumulu ),Phaseolus aureus (pesalu),Pisum sativum (batani)

Veg. Characters: mesophytes,plants show great diversity in habit,twainer (Dolichos) tendrillar climber (Pisum),root nodules with Nitrogen fixing bacterium Rhizobium with pink pigment leg-haemoglobin.
Leaf: cauline,alternate,stipulate,foliacious in Pisum,pulvinate leaf base,simple.pinnately,trifoliate compound leaf(Dolichos),entire leaf in Lathyrus,terminal leaf lets in Pisum modify into tendrils,leaflets into spines in Ulex.
Floral characters:inflorescence axillary or terminal,raceme (Crotalaria ),paniculate.
Flower: bracteate.bracteolate,pedicellate,complete,bisexual,pentamerous,perigynus,thalamus cup shaped,zygomorphic due to Papilionaceous corolla.
Calyx: 5,gamosepalous,valvate,odd sepal anterior in position.
Corolla: 5, free, Papilionaceous with bigger posterior Vexillum,two lateral Alae,two boat shaped Carina towards anterior side enclosing the stamens ,gynoecium,decendingly imbricate.
Androecium: 10,didelphous,9+1 in Dolichos,monadelphous in Crotalaria,anthers dithecous,introrse,longitudinal dehiscence.
Gynoecium: monocarpellary,unilocular,half-inferior,superior(Crotalaria),many ovules in two vertical rows on marginal placentation,long style, simple stigma,nectar gland at base.
Floral Formula:Br,Brl,%,O,K(5),C1+2+(2),A(9)+1,G1-
Pollination: Protandrous favouring croos pollination.Piston mechanism-essential organs move like Piston,when the insect alights on wings,pressed them,keels open, stigma comes out receiving pollen,then filaments come out shedding pollen on insect.
Fruit:legume in Dolichos,geocarpic in Arachis,samara in Pterocarpus,Dalbergia.
Seed: nonendospermic,dicotyledonous,store proteins in large amounts.
Economic importance:1)pulses are rich source of proteins.2) pods are vegetables
Exolichos, Glycene.3)Ground nut oil from Arachis hypogea,Soya bean oil from Glycene max.used in cooking 4)fodder from Crotalaria, Phaseolus.5)fibre(sunhemp) from Crotalaria juncea.6) seeds as condiment,leaves as vegetable ex:Trigonella.7)blue dye,Indigo from Indigofera tinctoria 8) musical instruments from wood of Pterocarpus santalinus.9)furniture from wood of Dalbergia latifolia.
Imp. Characters: 1) roots –nodular,help in N2 fixation.2)leaves-stipulate,pulvinate,show sleeping movements,3)flower-perigynus,thalamus cup shaped,odd sepal anterior,Papilionaceous corolla,descendingly imbricate aestivation,odd petal posterior,androecium 10 didelphous,Gynoecium monocarpellary,marginal placentation,4)Fruit- legume or pod.

-12-
ASTERACEAE: most evolved family in Dicots,Being Aster as nomenclatural type,with suffix acae(absent in Compositae),named as Asteraceae as per ICBN.
Examples: Sys.Position:Cla: Dicotyledonae.
Carthamus tinctorius(safflower) Sub.Cla: Gamopetalae,
Chrysanthemum indica(chamanti) Series: Inferae,
Cichorium intybus(chicory) Ord: Asterales,
Eclipta alba(bringaraj),Tagetus erecta(banthi) Fam: Asteraceae.
Helianthus annuus (sunfliwer),Tridax procumbens(gaddi chamanti)

Veg. Characters: fasciculated tuberous roots in Dahlia and Cichorium,herbaceous stem contains oil passages and latex,prostrate decumbent(Tridax),Launea is runner,in Helianthus tuberosus undergroun tuber stores inulin,leaves simple covered by hairs,compound in Dahlia.
Floral characters: head inflorescence highly evolved,homogamous with Disc florets only in Vernonia,with Ray florets only in Chrysanthemum,heterogamous with central Disc florets surrounded by peripheral Ray florets in Tridax.
Disc floret: central sessile,bracteate,actinomorphic,complete,pentamerous,epigynous.
Ray floret: peripheral,sessile,bracteate,zygomorphic due to ligulate corolla,incomplete,unisexual female.pentamerous, epigynous.
Calyx: reduced to pappus,persistent,absent in Xanthium,helps in fruit dispersal.
Corollaisc=5,gamopetalous,tubular,valvate. Ray=5,two reduced ,three form tongue shaped ,gamopetalous,valvate,nectar glands at base.
Androecium: Disc= 5,epipetalous,syngenesious(filaments free,anthers united) hooded,dithecous,introrse,longitudinal dehiscence. absent in Ray floret.
Gynoecium:similar in both Disc &Rayflorets, bicarpellary, syncarpous, unilocular, inferior,single ovule on basal placentation.style terminal,stigma bifid,passes through united anthers.
Floral formula: Disc floret:Br,Ebrl,+,O,K pappus,C(5),A(5),G(2)_
Ray floret:Br,Ebrl,%,O,Kpappus,C(5),A0,G(2)_
Pollination: protandrous,entamophily,anemophily in Xanthium,safty mechanism(bending of stigma lobes receiving self pollen, when cross pollination fails).
Fruit: single seeded cypsela,persistent pappus provide parachute mechanism. In Xanthium hhoklike spines help in dispersal by animals.
Economic importance:1) stem tubers of Helianthus tuberosus,root tubers of Dahlia are edible.2) Lactuca sativa is leafy vegetable.3) from seeds of Carthamus tinctorius safflower oil,Helianthus annues sunflower oil is extracted. 4) chicory from the roots of Cichorium intybus.5) antihelmenthic drug Santanine from the flower heads of Artemisia vulgaris. 6) Eclipta alba used in hair tonic.7) insecticide Pyrethrum from flowers of Chrysanthemun cinerariaefolium.
Imp.Characters(advanced characters):1) plants-herbaceous,veg.parts with internal oil cavities.2)head-homogamous,heterogamous,reduced florets,3) calyxappus persistent,helps in fruit dispersal,4) stamens: epipetalous,syngenesious,hooded,
5) gynoeciumicarpellary syncarpous,unilocular,inferior ovary,single basal ovule.6)fruit:Cypsela,parachute mechanism.

-13-
SOLANACEAE.
Examples: Sys.Position:
Atropa belladonna (belladonna) Class: Dicotyledonae
Capsicum fruitiscens (chilly) Sub.cla: Gamopetalae
Cestrum nocturnum (night queen ) Series: Bicarpellatae
Cestrum diurnum ( day king ), Orderolemoniales,
Datura metal (thorn apple) Fam: Solanaceae.
Lycopersicon esculentum (tomato ) Nicotiana tabacum (tobacco)
Solanum melongena (brinjal ), Solanum tuberosum (potato ), Withania somnifera (aswagandha )

Vegetative characters:Solanum surattense is xerophyte,stem tuber in Solanum tuberosum,adnation of petiole with stem,Internally stem shows bicollateral vascular bundles(phloem on either side of central xylem,separated by cambia),petiole adnates with internode,simple pinnately lobed leaves.

Floral characters:
Inflorescence: cymose,axillary,terminal in Datue,extra axillary scorpiod cyme.
Flower: bracteate,ebracteolate,bisexual,pentamerous,hypogynous,obliquely zygomorphic due to rotate carpels.
Calyx: 5,gamo,valvate,persistent,macrescent(does not grow after fertilization),exrinjal, accrescent(grow along with fertilized ovary after fertilization)exhysalis.
Corolla:5,gamo,valvate or plicate.
Androecium: 5,epipetalous,anther large,dithecous,longitudinal dehiscence in Datura, porous dehiscence in Solanum.
Gynoecium: bicarpellary syncarpous bilocular, made tetralocular by false septum,ovules on axile placentation,ovary oblique,posterior carpel to right side,anterior carpel to left sideat 45 anglemade the flower obliquely zygomorphic,terminal style,capitate stigma.
Floral Formula: Br,Ebrl,+,O,K(5),C(5),A5,G(2)_
Pollinationrtandrous,protogynous(Solanum),entemophily,self pollination (Nicotiana).
Fruit: berry in brinjal,tomato.chilly,septifragal capsule in Datura,Nicotiana,

Eco.Imp: 1) Vegetables-potato(Solanum tuberosum),brinjal(Solanum melongena),
Tomato(Lycopersicum esculentum),chilly(Capsicum fruitiscens)2)alkaloid-capsine
From Capsicum used as condiment.3) alkaloid-Nicotine-from leaves of Nicotiana. 4) atropine-from Atropa belladonna used in plasters.5) Solanum surattense,Datura stramonium,cures asthma,6) Withania somnifera-root extract used as rejuvenating tonic.

Imp. Characters: 1) bicollateral vascular bundles in stem,2) adnation of petioles with axis.
3)persistent calyx.4) bicarpellary syncarpous,bilocular made tetralocular,by false septum,ovules on swollen axile placentation,5) obliquely placed superior ovary,due to rotation,6)fruit berry or capsule.
-14-
LILIACEAE:
Examples: Sys.Position:
Allium cepa ( onion ) Class: Monocotyledonae
Allium sativum (garlic ) Series: Coronariae,
Aloe barbadensis (aloe ) Family : Liliaceae.
Asperagus racemosus (sathamuli ),Colchicum autumnale
Ruscus aculeate,Smilax zeylanica,Yucca gloriosa.

Vegetative Characters: mesophytes (Allium ),xerophytes ( Ruscus ),perennial shrub (Aloe ),climbers ( smilax ),fasciculated tuberous roots (asparagus ),bulb (Allium) Rhizome ( Gloriosa ),corm ( Colchicum ),naked bulb (Lilium ),tendrillar climber (Gloriosa, Smilax ),In Yucca, Dracaena aerial stem shows anamolous secondary growth,cladophylls ( Ruscus,Asparagus ),vegetative propagation by axillary buds ( Lilium bulbiferum ),suckers ( Aloe ).
Leaves: radical (Allium),cauline (Smilax),parallel venation, reticulate ( Smilax) succulent leaves (Aloe, Yucca),scales ( Asparagus,Ruscus),leafbases fleshy (Allium,Lilium ),In Gloriosa leaf tip, in Smilax stipules modify into tendrils,
Leaf apex with epiphyllous buds in Scilla.

Floral Characters:
Inflorescence:racemose,simple raceme in Asparagus,panicle in Yucca,umbel in Allium,solitary terminal in Lilium,axillary in Gloriosa,stalk like peduncle emerging from underground stem is called scape.ex: Allium.
Flower: bracteate,ebracteolate,pedicellate,actinomorphic,trimerous,bisexual,hypogynous, unisexual in Ruscus,Smilax.
Perianth:6 tepals,3+3 in two whorls,polyphillous in Lilium,gamophyllous in Aloe,petaloid,odd petal is anterior in position,valvate.
Androecium: 6,3+3,free,epiphyllous,dithecous,introrse,longitudinal dehiscence.
Gynoecium: tricarpellary syncarpous trilocular,ovules on axile placentation,superior ovary,terminal style,trifid stigma,capitate.
Floral formula: Br,Ebrl,+,O,P3+3,A3+3,G(3)_
Pollination:entamophilous,protandrous in Allium,protogynous in Colchicum,Pronuba yuccasella, moth associates in Yucca,herkogamy in Gloriosa.
Fruit: berry in Asparagus,loculicidal capsule in Lilium,septicidal capsule in Gloriosa.
Seed: monocotyledonous,endospermic,polyembyony in Allium.

Eco.Imp: 1) bulbs of Allium edible,bactericidal 2) cloves of Allium sativum spice,medicinal curing gastric,heart complaints,3) fasciculated tuberous roots of Asparagus are edible.4) Aloe treats piles.5) roots of Smilax source of Sarsaparilla medicine,6) colchicines,chemical mutagen,from corms of Colchicum autumnale.

Imp.Cha: 1) perennial underground stems with fibrous roots 2) simple leaves parallel venation3) flowers actinomorphic,trimerous,perianth homochlamydeous,petaloid,4)Gynoecium-tricarpellary syncarpous,trilocular,ovules on axile placentation,superior ovary,5)fruit capsule.
-15-

INTERNAL ORGANISATION
INTERNAL STRUCTURE OF DICOT STEM. Ex: Helianthus annuus( sunflower )
T.S of primary Dicot stem shows three zones:
I) epidermis: Outer most layer. Rectangular cells are arranged compactly without inter cellular spaces.Cuticle deposited on the outer surface is made up of waxy substance cutin.Stomata are peresent. Multicellular uni or biseriate trichomes develop on epidermis. Cuticle, trichomes check water evaporation.They protect the stem from high temperature.Trichomes prevent the entry of pathogenic organisms Through stomata ,epidermis allows exchange of gases and promotes transpiration.
II) Cortex: It is the part between epidermis and stele. It shows:
1) Hypodermis: Outermost part of cortex,beneath epidermis.,made up of 3 to 6 rows of collenchyma.The cells are compoactly arranged without intercellular spaces,due to excessive thickening of cell corners.It gives elasticity to the stem. By possessing chloroplasts it helps in the production of food material.
2) General cortex: Below the hypodermis,5 to 10 rows of parenchyma are present.The cells are thin walled isodiametric,with or without intercellular spaces.Outer layersd contain chloroplasts,inner layers with leucoplasts,performing assimilation and storage respectively.
3) Endodermis:Innermost layer of cortex.Cells are barrel shaped,compactly arranged without intercellular spaces.Radial and transverse walls show lense shaped thickenings called casparian bands.Endodermis is called starch sheath as it contains starch grains.
III) Stele:central conducting cylinder. It is well developed. It consists of :
1) Pericycle: It is between endodermis and vascular bundles.It is formed of Sclerenchyma,in the form of semilunar patches,intervening with parenchyma masses.
2) Vascular bundles: 15 to 20 in circular ring.The arrangement of vascular bundles in a ring is called Eustele.It is concerened with conduction of water,salts and food materials.Each vascular bundle is top shaped ,phloem outerside,xylem innerside,with meristem inbetween(fascicular cambium) on the same radius. Vascular bundle is called conjoint (xylem and phloem form one bundle ),collateral (xylem and phloem on same radius),open(cambium inbetween xylem and phloem ). Xylem is endach (protoxylem towards center).Xylem has vessels,xylem parenchyma,xylem fibres.Phloem has sieve tubes,companion cells,phloem parenchyma.
3) Medulla: central part of stele.It is filled with parenchyma storing food material.
4) Medullary rays:Thin walled living,radially elongatedfrom medulla to periphery,in between the vascular bundles are called medullary rays.They help in lateral conduction

-16-

INTERNAL STRUCTURE OF MONOCOT STEM. Ex: Zea mays.

T.S. of Monocot stem shows:
1) Epidermis: Outermost layer.Rectangular living cells are compactly arranged without intercellular spaces. On the outer surfacewaxy layer cuticle prevents evoporation of water from plant body.Numerous stomata in epidermis help in exchange of gases.Trichomes are absent.
2) Hypodermis: A clear cortex is absent. Formed of 3 to 4 rows of compactly arranged sclerenchyma cells,without intercellular spaces,giving mechanical strength to stem.
3) Ground tissue: Below Hypodermis,remaining part is extensively filled with soft parenchyma tissue called Ground tissue,with intercellular spaces.The tissue with chloroplasts synthesizes and stores food material.Endodermis is absent.
4) Vascular bundles: Numerous.Scattered in ground tissue and the arrangement is called Atactostele,an advanced character.Inner are bigger and outer are smaller in size.Each vascular bundle is called Fibrovascular bundle enclosed by a sheath of sclerenchyma fibres.Each vascular bundle is oval,conjoint,collateral,closed(cambium is absent ).Xylem is endarch(proto xylem towards center).Xylem shows two metaxyla,two protoxyla in Y shape.One protoxylem is crushed forming lysigenous cavity storing water.,forming protoxylem laculae.Xylem consists of tracheids,vessels,fibres,xylem parenchyma.Phloem consists of sieve tubes,companion cells.Phloem parenchyma is absent.Medulla ,medullary rays are absent.

Differences between internal structure of Dicot stem and Monocot stem.

Feature Dicot stem Monocot stem.

1) trichomes: present absent.
2) cortex: well developed.separated into highly reduced,
hypodermis,general cortex,endodermis. With only parenchyma.
Hypodermis: collenchymatous. Sclerenchymatous.
Endodermis: starch sheath. Absent.
3) stele:
Pericycle: sclerenchymatous. Absent.
Vascular wedge shaped,eustele. Oval,scattered,atactostele.
Bundles: Bundle sheath is absent. Fibrovascular ,
Sclerenchymatous .
Cambium: open closed.
Xylem: more,in serial order. 4, Y shaped,
2 meta xyla,2 proto xyla.
1 protoxylem into
protoxylem lacuna.
Lysigenous will not form. Stores water.
Cavity:
Phloem parenchyma: present. Absent.
--17—
INTERNAL STRUCTURE OF DICOT ROOT.

It shows:
1. Epidermis: Outermost living layer without cuticle and stomata.It is also called epiblema as it produces root hairs.Comparitively smaller epidermal cells forming root hairs are called trichoblasts.Epidermis gives protection and with root hairs help in absorption.
2. Cortexigger than stele,showing:
a) Exodeermis: outermost layer, formed of 2-3 rows of thick walled suberised cells .It prevents exit of water from cortex.
b) General cortex: Below Exodermis, it is formed of several rows of thin walled living parenchyma.With leucoplasts it stores food. Thin walled cells help in conduction of water towards xylem.
c) Endodermis: Innermost layer.Single row of barrel shaped ,compactly arranged cells.Cells show deposition of lignin and suberin on the radial walls and transverse walls called casparian thickenings.Opposite to protoxylem,cells without casparian bands form passage cells,helping in the entry of water from cortex to stele.
3. Stele: Smaller than cortex, stele shows:
a) Pericycle: Single layered thin walled,rectangular cells formthe origin of lateral roots.Some cells form cambium during secondary growth.
b) Vascular bundles:Xylem and Phkoem alternate,on separate radii.Xylem exarch,with protoxylem towards pericycle.Xylem may be monarch(Trapa natans),Diarch (Nicotiana tabaccum),Triarch(Pisum sativum),Pentarch (Ricinus communis),Octarch (Castanea).Parenchymatous ground tissuein between xylem and phloem is called conjuctive tissue,helping in the storage of food material.
c) Medulla ; Small or absent due to union of meta xyla.If present,Parenchymatous storing food and water.
Differences between Dicot root and Monocot root.
Feature Dicot root. Monocot root.

1. cortex: relatively smaller. Bigger.
2. Pericycle: gives rise lateral roots, produces only lateral roots.
Vascular cambium,
During secondary growth.
3. Xylem: monarch to tetrarch. Polyarch.
4. Medulla: small or absent. Very big.
5. Secondary growth: occurs. Absent.
Differences between Stem and Root.
feature stem root
1. vascular bundles: collateral, conjoint. Radial.
2. endodermis: not clear very clear
3. xylem: endarch exarch
4.conjunctive tissue. Absent present
--18—
Transverse section of Dorsiventral ( Dicot ) leaf .
It shows three main parts:
I. Epidermis: Leaf is flattened,showing upper epidermis on adaxial surface and lower epidermis on abaxial surface.Epideermis is made up of single layer of barrel shaped cells ,compactly arranged without intercellular spaces.Externally covered by waxy layer called cuticle.More stomata on lower surface.Multicellular hairs are present on both surfaces.Epidermis protects inner tissues,helps in gaseous exchange by stomata.
II. Mesophyll: Tissue between upper and lower epidermal layers.It is hin walled parenchyma with chloroplasts.Seperated into upper palisade parenchyma and lower spongy parenchyma.
a) Palisade parenchyma: Below upper epidermis,1-3 vertical rows of elongated ,columnar cells,with narrow intercellular spaces.Larger number of chloroplasts are found nearer to cell wall.Helps in carbohydrate synthesis in light.
b) Spongy parenchyma: 3-5 rows of irregularly shaped parenchyma with large intercellular spaces,present towards lower epidermis.Intercellular spaces nearer to stomata are very large forming air cavities.Number of chloroplasts is less ,than palisade cells.Upper surface is dark green and lower surface is light green in colour.(dorsiventral leaf).Spongy parenchyma primarly helps in gaseous exchange,besidessynthesis of food to a lesser extent.
c) Vascular bundles: They are in mesophyll in the form of veins.Veins help in supplying water,salts, food,to allover the leaf surface,besides giving mechanical strength to leaf.Bigger vascular bundles at the base of leaf,smaller towards margins,apex.Vascular bundles are conjoint,collateral,closed.Xylem on upper side,phloem on lower side.Around each vascular bundle ,bundle sheath(border parenchyma) with compact specialized mesophyll cells form.Extending from the bundle sheath cells towards upper and lower epidermal layers,present bundle sheath extensionshelping in the conduction of food from mesophyll to vascular bundles.

TRANSVERSE SECTION OF ISOBILATERAL (MONOCOT) LEAF.

T.S.of isobilateral leaf shows:
I. Epidermis: On both upper side (adaxial side ) and lower side (abaxial side ) epidermal cells are barrel shaped.,compactly arranged.Epidermal hairs are absent.Waxy layer cuticle is present on the outer surface.Stomata are equal on both the surfaces.In grasses some enlarged,thin walled specialized cells filled with water are called bulliform cells or motor cells.These cells help in rolling and unrolling of leaf.Epidermis helps in transpiration and exchange of gases,besides giving protection to the inner tissues.
II. Mesophyll: The ground tossue present between the two epidermal layers is called mesophyll.It consists of columnar or spongy cells.,loosely arranged ,with intercellular spaces.They contain chloroplasts.Patches of sclerenchyma are

--19--
present beneath the epidermis,giving mechanical strength to leaf.Mesophyll is photosynthetic tissue.
III. Vascular bundles: Parrallel veins represent vascular bundles.They are conjoint,collateral,closed.Xylem towards upper eoidermis,phloem is below the xylem.Around each vascular bundle,specialized mesophyll cells,formbundle sheath.It may be rwo layered,outer chlorenchyma,and inner thick walled layerwithout chloroplasts.Schlerenchyma bundle sheath extensions ,on either side of vascular bundles,towards epidermal layers give mechanical strength to leaf.Bundle sheath cells with casparian thickenings on walls,are homologous to endodermis.

Differences between Dicot leaf and Monocot leaf.

Dicot leaf Monocot leaf.

1. stomata. More on lower epidermis. Equally distributed on both sides.

2. bulliform cells. Absent. Present on upper epidermis.

3. mesophyll. Differenciated into upper palisade undifferenciated.
And lower spongy parenchyma.

4. bundle sheath parenchymatous. Sclerenchymatous.
Extensions.

Comments