Root | Note 1 |standard 11| morphology of flowering plants | notes | NCERT| Biology

 

 

Standard 11 
Morphology of flowering plants

Morphology of flowering plants| roots| NCERT short note| Best biology short note | standard 11

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Note 1

The Root | Regions of root| Modification of root

Root of dicotyledonous plant

Direct elongation of radicle - formation of primary root 

The roots grow inside the soil

It has lateral roots of several orders - referred to as secondary, tertiary etc roots 

Primary root+ its branches - tap root system 

Example : mustard plant

Root in monocotyledonous plants

Primary root- short lived

Primary root replaced by a large number of roots

Originates from the base of the stem

This forms fibrous roots .

Example : wheat plant

Adventitious roots

Roots that arise from parts of plant other than radicle

Example : grass, Monstera, banyan tree

Functions of root system:

• Absorption of water from soil

• Absorption of minerals from soil

• Providing anchorage to parts of plant

• Storing nutrients 

• Synthesis of growth regulators 

> Regions of the Root

Root cap

Situated on the apex of the root

It is a thimble like structure

Function: protects tender apex of the root -when it makes way through soil

Region of meristematic activity

Situated at few millimeters above root cap region

Cells of this region are very small, thin-walled and with dense cytoplasm 

They get divided repeatedly 

Region of elongation

Cells proximal to the region of meristematic activity form region of elongation 

They undergo rapid elongation and enlargement 

It is responsible for the growth of root in length. 

Region of maturation 

It is proximal to region of elongation 

Cells of elongation zone gradually differentiate and mature. - this way region of maturation is formed

Root hair 

Made out of epidermal cells from region of maturation 

They form very fine and delicate, thread-like structures - called as root hairs 

Function:  absorb water and minerals from soil

> Modification of Root

Root in some plants change their shape and structure 

They become modified to perform functions other than absorption of water and minerals

They are modified for support, storage of food and respiration

Modification for storage of food:

Tap roots of carrot, tap roots of turnip and adventitious roots of sweet potato 

They get swollen and store food. 

Modification for support 

Prop roots - Banyan tree-  hanging structures that support the tree   

Stilt root - roots coming out of the lower nodes of the stem - maize and sugarcane 

સ્તંભમૂળ

Pneumatophores - plants growing in swampy areas - many roots come out of the ground and grow vertically upwards - help to get oxygen for respiration- Rhizophora

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Manish Mevada 

Urvi Bhanushali