MORPHOLOGY OF FLOWERING PLANTS

1. INTRODUCTION2. THE ROOT3. THE STEM4 THE LEAF4. THE LEAF5. THE INFLORESCENCE6. THE FLOWER7. THE FRUIT8. SUMMARY

INTRODUCTIONyMorphology deals with the study of

shape size and structure of the plantshape , size and structure of the plant body.yFlowering plants are called

Angiosperms , it consist of an axis with g p ,an underground Root system and Aerial Shoot systemAerial Shoot system .

yThe root , shoot and leaf constitute the vegetative parts of the plant body.vegetative parts of the plant body.

yThe Flower , Fruit and seed constitute the Reproductive parts of the plant bodyp p p yE.g., Mustard plant.

THEROOTy It is the Underground part of the plant ,

originates from the radicle of the germinatingoriginates from the radicle of the germinating seed .

yThere are mainly two types of Root system 1 Tap root system seen in dicots1. Tap root system seen in dicots2. Fibrous root system seen in monocots

y Major functions of Root : (a) Fixing a plant in soil(a) Fixing a plant in soil .(b) To hold soil particles.( c) Absorptions of water and

mineral saltsmineral salts.

(a) TAP ROOT (b) FIBROUS ROOT

MODIFICATIONS OF ROOTMODIFICATIONSOFROOTThe roots in some plants changeThe roots in some plants change there shape and structure and b difi d f ibecome modified for various functions.

1. Storage The primary root becomes thick and fleshy due to food storage .

e.g., Radish, Beetroot, Carrot.g , , ,2. Support Stilt root of Maize ,Sugarcane

Prop root of Banyan treeProp root of Banyan tree . 3. Respiration They are also called pnematophores help to get oxygen forpnematophores , help to get oxygen for respiration.

THESTEMyStem is the aerial part of the plant b d It b b h lbody. It bears branches, leaves , flowers and fruit.yThe stem also bears nodes and i t d internodes.

yThe main function of the stem(a) It conducts water minerals and(a) It conducts water , minerals and

photosynthates .

(b) Some stems performs the function of ( ) pstorage of food , support , protection and vegetative propagationand vegetative propagation.

THESTEM

MODIFICATIONOFSTEMyThese may be of three types

(i) Underground modification of stem :Rhia. Rhizome e.g., Ginger ,Turmeric etc.,

b. Bulb e.g., Onion , Garlic .c. Tuber e.g., Potato.g ,

(ii) Sub-aerial modification of stem :R O lia. Runner e.g., Oxalis

b. Offset e.g., Pistia S k B Pi lc. Sucker e.g., Banana , Pineapple

(iii) Aerial modification of stem :St T d il C ba. Stem Tendril e.g., Cucumber , Watermelon

b Thorn e g Citrus Durantab. Thorn e.g., Citrus , Durantac. Cladode e.g., Asparagusd Phylloclade e g Opuntiad. Phylloclade e.g., Opuntia ,

Euphorbia

THE LEAFy The Leaf is a lateral ,flattened

structure of plant in most of thestructure of plant , in most of theplants it is green in colour , becauseof the presence of chlorophyllof the presence of chlorophyll .

P t f l f E h l f b i lly Parts of a leaf : Each leaf basicallyconsist of three parts i.e. lamina ,

ti l d l f bpetiole and leaf base.

y Venation : It is the arrangement of veins and vein lets in the leaf. It is of two types

(i) Reticulate Venation : Here vein lets make a network . E.g., Dicot plants.

Parallel Venation : Here Veins run parallel to each other on the lamina of the leaf. E.g., Monocot leaves.

TYPESOFLEAVES

y There are mainly two types of leavesy Simple Leaf : The lamina is single or

undivided. E.g., Hibiscus g ,.

y Compound Leaf : The lamina is fullyy Compound Leaf : The lamina is fully broken up into clear segments or leaflets E g Neemleaflets . E.g., Neem.

y Phyllotaxy : It is the arrangement of leaves on branch or stem . It is of three types(i) Alternate : A single leaf at a node

E.g., Sunflower , Mustard.(ii) Opposite : Two leaves at a node . ( ) pp

E.g., Ocimum.(iii) Whorled : More than two leaves in a(iii) Whorled : More than two leaves in a whorl at a node E.g., Nerium .

MODIFICATIONS OF LEAVESMODIFICATIONSOFLEAVESy Leaves are often modified to

perform functions other than photosynthesis . They are p y y

(i) Tendrils : for climbing e.g., Peas(ii) S i f d f O ti(ii) Spines : for defence e.g., Opuntia

(cactus)(iii) Storage : the fleshy leaves of onion

THEINFLORESCENCE

y It refers to the mode ofy It refers to the mode of arrangement of the flower on the floral axis .

y The Inflorescence is of mainly twoThe Inflorescence is of mainly two kinds

(i) R th i i(i) Racemose : the main axis continues to grow and it is called indefinite inflorescence.

(ii) Cymose : The main axis terminates(ii) Cymose : The main axis terminates into a flower hence limited growth , it is a definite inflorescenceit is a definite inflorescence . E.g., Hibiscus , Jasmine

Racemose inflorescence Cymose inflorescence

THEFLOWERyThe flower is a modified shoot meant for the reproduction of themeant for the reproduction of the plant .

yThe stalk of the flower is called di l d th ll t ipedicel and the swollen part is

called thalamus .

yIt is comprised of four whorls ,which are arranged on thalamus they areare arranged on thalamus , they are (a) Calyx The outer most whorl composed of sepalscomposed of sepals(b) Corolla The second whorl consisting of petals consisting of petals (c) Androecium The third whorl composed of stamenscomposed of stamens(d) Gynoecium The innermost whorl made up of carpelsmade up of carpels

yCalyx and Corolla are calledCalyx and Corolla are called Accessory whorls , in some plants the are not differentiatedplants they are not differentiated from one another such case they yare termed as Perianth . Each part of Perianth is calledEach part of Perianth is called tepal.

THEFLOWERA d i d G i ll dyAndroecium and Gynoecium are called essential whorls .y In most of the flowers all the four whorls

are found , such flowers are called Complete ,bisexual flowers .E.g.,Hibiscusy In a flower out of four whorls any one y

essential whorl is absent it is called Incomplete, unisexual flower. pE.g., cucurbits.

yOn the basis of symmtery flower can be of the following typesbe of the following types1. Actinomorphic : these flowers can b di id d b ti l lbe divided by any vertical plane into two equal and similar halves . E.g., Mustard , Brinjal .2 Zygomorphic : these flowers can be2.Zygomorphic : these flowers can be divided into two equal halves by only one vertical divisionone vertical division . E.g., Pea , Ocimum

AESTIVATIONy The arrangement of sepals and petals with g p p

respect to one another in floral bud is called aestivation .T f ti tiy Types of aestivation

1. Valvate : the sepals and petals are arranged in a whorl which just touch one another at the marginewhorl which just touch one another at the margine they do not overlap. E.g., Calotropis

2. Twisted : here one margin of the sepal or petal sted e e o e a g o t e sepa o petaoverlap on the next sepal or petal , and the next margin is overlapped by the proceeding one, resulting in a twisted appearanceresulting in a twisted appearance . E.g., Cotton ,Ladys finger.

3 I b i t h th i f l3. Imbricate : here the margins of sepals and tepals overlap another but not in particular directionparticular direction

4 Vexillary : here out of five petals the4. Vexillary : here out of five petals the largest overlaps the two lateral petals which in turn overlap the two smallest ppetals E.g.,Pea .

Valvate Twisted Imbricate Vexillary

THEFRUIT

yFruit may be defined as a ripened ovary.

yThe fruit wall is called PerecarpThe fruit wall is called Perecarp

yUsually the three layers of pericarp are> The outer most layer is known as ythe epicarp> Middle layer is known as the> Middle layer is known as the mesocarp> Inner most layer is known as the endocarp endocarp

E.g., Mango , Coconut

(a) Mango (b) Coconut

SUMMARYFl i l t hibityFlowering plants exhibit enormous variation in shape, size , structure

d f t iti lif h bitmode of nutrition , life span , habit and habitat.

yThey have well developed rootThey have well developed root and shoot system

yGenerally , dicotyledonous have y , ytap root system and monocotyledonous have fibrous yroot system.

yThe root in some plants get modified for storage of foodmodified for storage of food , mechanical support , and respirationrespiration.

yThe shoot system is differentiated into stem , leaves , flowers andinto stem , leaves , flowers and fruits .yMorphologically the stem showsyMorphologically the stem shows nodes and inter nodes .yStems also get modified toyStems also get modified to perform diverse functions such as storage vegetative propagationstorage , vegetative propagation and protection under different conditionsconditions .

yLeaves are the lateral outgrowth of the stem usually green inof the stem , usually green in colour to perform the function of photosynthesis. They also get modified into other structures suchmodified into other structures such as tendrils , spines for climbing and protection respectivelyand protection respectively.

yThe flowers are arranged in diff t t f i fldifferent types of inflorescences.yFlowers exhibit enormousyFlowers exhibit enormous variation in structure , symmetry ,

iti f d tposition of ovary and arrangement of sepals , petals , ovules.p , p ,yAfter fertilization the ovary is

t d i t f it d thconverted into fruits and the ovules into seeds .

SOME IMPORTANT POINT TO REMEMBERyAuxiliary bud : A bud that arises in

the axil of leaf .the axil of leaf .yAdventitious Roots : These roots arise

f t f th l t th thfrom any part of the plant other thanradicle e.g., rihizophorayBisexual: flowers having male and

female reproductive partsfemale reproductive parts

yBract : it is a small leaf with relativelyundeveloped blade in axil arises a flowerundeveloped blade in axil arises a floweror a branch of inflorescence.B d t d d l d h tyBud: a compact under developed shootwhich contains shortened stem and floral

tpart.yCotyledeon: the first leaf of the embryo of

the seed plant which is usually simpler instructure and have reserved food material.

yCompound leaf: lamina is fully brokenp yup into clear segments.yColeorhiza: protective covering of theyColeorhiza: protective covering of the

radical in the monocot leaf.yColeoptile: it refers to the protective

sheath of the plumule in monocot seeds.sheath of the plumule in monocot seeds.

yDicotyledons: the seeds having twoyDicotyledons: the seeds having twocotyledonsyDry fruit: A fruit possessing dry pericarpy Epiphytes: The plant which grow ony Epiphytes: The plant which grow on

the other plants but do not getnourishment from themnourishment from them

Example, Orchidsp

yEpicalyx : the small greenappendages below the sepals make aappendages below the sepals make awhorl, Example, HibiscusyEpicarp: Outer layer of the fruityEndospermic seed: Seed in whichyEndospermic seed: Seed in which

food is stored in the endosperm.yFlower: modified shoot meant for

sexual reproduction and bares fruitspand seeds

yFalse fruit: A fruit in which any other part other than ovary takes part in itspart other than ovary takes part in its formationH b It f t ll l t h iyHerb: It refers to a small plant having soft stemyInflorescence: It is the arrangement of

the flowers on the branch of the plantthe flowers on the branch of the plant.

yLeaf : Flattened green structure whicharises as a lateral appendages fromthe stem or branches from the nodeand bares a bud on its axil.yMesophytes: The plants that grow inyMesophytes: The plants that grow in

habitats having moderate condition.yMonocarpic: The plant which bare

flower and fruits once in life

yParthinocarpic Fruit: A fruit whichdevelops without fertilization,develops without fertilization,yPerianth: The part of the flower where

calyx and corola are fusedcalyx and corola are fusedyPlacentation: The arrangement ofg

ovules in the ovary

yPhyllotaxy: The arrangement on theb h f tbranch of stem.yPollen: These are the microspores of seed

plants produced in large numbers.ySeeds: The structure that developes fromp

the ovule following fertilization inangiosperms and gymnosperms .g p gy pyShrub: Medium sized plants having

branches which arise from the soilbranches which arise from the soil.

ySyncarpous ovary: Its a ovary havingy p y y gnumber of carpls fused,

Example: TomatoExample: TomatoyTendril: A slender but spirally coiled

structure trhat helps the plants toclimb.climb.yApocarpus ovary: Ovary where the

carpls are not fusedcarpls are not fused .