Morphology of flowering plants

Morphology is the study of external root , leaves , stem , fruits and flowers

Types of roots

Tap root :1)Consist of roots , and lateral branches called secondary and tertiary etc

2) it is branched

3)Tap root is found in dicotyledons plant

4) example are mango and banana

Fibrous root:1) In fibrous root primary and lateral branches are absent, and roots emerges from the base of the stem

2) it is unbranched

3) it is found in monocotyledons plant

4) examples are cocounut and grass

Adventitious roots: 1) roots which arise from the parts of the plant other than the radicle

2) examples are grass and monestra

Regions of the root

Root cap: It covers the tip of the root and also protects it .

Region of meristematic activity: In which cells diivides rapidly,the cells of this region are small , thin walled and with dense protoplasm.

Region of elongation : they are responsible for the growth of the root in length as they undergo rapid elongation and enlargement

Region of maturation: it consists of matured cells and root hairs. Root hairs absorb water and minerals from the soil .

Functions of roots

1) absorption of water and minerals

2) provides anchorage

3) storage of reserved food particles

4) synthesis of plant growth regulators

Modification of roots A

Prop root: example BANYAN TREE

SStilt root : example MAIZE AND SUGARCANE

Modification of roots B

BREATHING ROOTS: Example is pneumatophora

They are found in rhizophora ,

This grows in swampy areas , many roots come out of the ground and grows vertically upward, this are called breathing roots , they have pneumatophora which helps to get oxygen.

Stem A

1)stem is a part of shoot system

2) It consists of branches leaves , fruits , flowers etc

3) it develops from plumule

4) stem bears nodes and internodes

Stem B Nodes and Internodes

NODES: The region of stem where leaves are born

INTERNODE: The portion between 2 nodes

•Stems have terminal buds : apical bud and lateral bud.

Stem C functions of stem

1) Conduction of water and minerals

2) Conduction of food (photosynthates)

3) spreading out branches and bearing leaves flowers and fruits

3) storage of food , protection and vegetative propogation

Modification of stemA

Underground stem-stores food ,

Examples are : potato and ginger

Stem tendril: develops from axillary bud , they are slender , spirally coiled and helps plants to climb

Examples are: cucumber and pumpkins

Thorns: develop from axillary buds, they are woody,straight and pointed , they protect plants from browsing animals.

Examples are: citrus and bougainvillea

Modification of stem B

Phylloclade

stems get modified into leaf like structure to perform photosynthesis and also storage

They are found in opuntia

Basal underground stem

Examples are banana and pineapple

Leaf A

Leaf is a lateral flattened structure borne on the stem

It develops from the auxiliary bud

It originates from the shoot apical meristems and are arranged in acropetal order

They are very important organs for photosynthesis.

Leaf consists of leaf base lamina and petiole

Leaf B venation

VENATION: Arrangement of veins and veinlets in the lamina of the leaf.

Venation are of 2 types

RETICULATE VENATION:when veinlets forms a network it is called as RETICULATE VENATION

It is found in dicotyledons

PARALLEL VENATION: Veins runs parallel to each other within the lamina it is called RETICULATE VENATION

It is found in monocotyledons

Types of leaves

SIMPLE LEAF :when the lamina is incised the incision donot touch the midrib

COMPOUND LEAF: when the incision of the lamina reach upto the midrib breaking it to number of leaflets

Compound leaves are of two types

pinnately compound leaf: leaflets are present on the rachis in opposite manner .

Example is curry leaves

Palmately compound leaf : leaflets are attached on the rachis at a common point

Example is silk cotton

Diagram a: pinnately b: palmately

Phyllotaxy

Pattern of arrangement of the leaves on the stem

1. Alternate arrangement:single leaf arise at each node

2. Opposite arrangement: a pair of leaves arise at each node and lie opposite to each other

3. Whorled arrangement: more than two leaves arise at each node and forms a whorl

Modification of leaves

1) storage : onion

2) leaf tendril for climbing:peas

3) spines for defense : cacti

5) insectivorous plant : pitcher plant

Inflorescence A

It is the arrangement of flower in the floral axis

Inflorescence B types of inflorescence

RACEMOSE: younger flowers are present on the top and older flowers are present on the bottom

It is an acropetal succession

Main axis continues to grow

CYMOSE: older flowers are present on the top and younger flowers are present on the bottom

It is a basipetal succession

Main axis terminates into a flower

Flower

Flower is the reproductive unit of angiosperms.

It' is meant for sexual reproduction

Single flower is called as solitary flower

Group of flowers is called as inflorescence

Symmetry of a flower

ACTINOMORPHIC(RADIAL SYMMETRY)

When the flower can be divided into 2 equal half in any radial plane

ZYGOMORPHIC(BILATERAL SYMMETRY)

When the flower can be divided into 2 equal half in one particular plane

ASSYMETRIC

When a flower cannot be divided into any plane

Bract

Reduce leaf found at the base of pedicel

Bractate: flower with bract

Ebractate: flower without bract

Merosity

No of floral appendages

Merosity is of three types : multiple of 3

2) tetramerous: multiple of 4

3) pentamerous: multiple of 5

Based on the position of the calyx Corolla and androcium and ovary on the thalamus flower is divided into

Hypogynous : gynoecium occupies highest position and other Parts are located below it

Ovary is superior

Example is china rose

Perigynous: gynoecium is situated in the centre other parts are on the rim of the thallamus

Ovary is half inferior

Example is rose

Epigynous: margin of the thallamus grows upward enclosing the ovary completely and fuses with it

Ovary is inferior

Example is guavva

Flower( 4 floral whorls ) A

Calyx

Calyx is called sepals

It's is the outermost whorl

It is the green leaf like and protects the flower in the bud stage

calyx can be divided into two types

1) polysepalous : free sepals

2)gamosepalous : United sepals

Flower B

Corolla

It's is bright coloured to attract the insects

Colour and shape varies

It' can be funnel tubular or bell shaped

Corolla can be divided into 2 types

1)polypetalous : free petals

2) gamosepalous: United petals

Aestivation A

Is the arrangement of sepals and petals in the floral bud with respect to the other members of the whorl

Aestivation B

Types of aestivation

Valvate

Twisted

Imbricate

Vexillary

Androecium

It is called stamen

It is a male reproductive structure

Stamens can be divided into

1) anther

2) filament

Anther is a bilobed structure with two pollen sacs in each lobe

Stamens when attached to Corolla (petals)

They can be divided into two types

Epipetalous: stamen attached on petals

Example is brinjal

Epiphyllous : stamen attached on the perianth

Example is flowers of Lilly

Free stamens are called polyandrous

United stamens can be divided into 3 types

1)monodelphous: 1 group example is china rose

2)diadelphous: 2 groups example is pea

3) polydelpus: 3 or more groups example is citrus

Perianth

In some flowers calyx and Corolla are not distinct and are termed as perianth

Gynoecium

It is called as carpel

Carpel consists of 3 parts

1) stigma: present on the tip , and it receives the pollen grain

2)style : connects stigma and ovary

3) ovary: swollen basal part , it consists of one or more ovules connected to the inner wall of ovary and is called placenta

Placentation

Arrangement of ovules within the ovary

Types of placentation

1) marginal: ovules are arranged on the margin

Example is green peas

2) axile: ovules are present at the axis of carpel

Example is lemon

3) pariental : ovules are present at the inner wall

Example is papaya

4) free Central : ovules are present at the Central axis

Example is capsicum

5)basal : single ovule attached at the base

Example is avacado