ROOTS

- Roots arise from parts of plant other than radicle are called adventitious roots. E.g. grass, banyan tree.

- Regions of root

- root at the apex is covered by a thimble like structure called as root cap, and the root cap protects the tender apex as it makes its way through the soil.

-region of meristematic activity: the region is very small, thin walled with dense protoplasm. They divide repeatedly.

-region of elongation: this area undergoes rapid elongation and enlargement and are responsible for the growth of the root in length.

-region of maturation: cells of the elongation zone differentiate and mature and form dis zone.

-MODIFICATION OF ROOT

-food storage: E.g. sweet potato, radish, carrot

-support: -prop roots: arise from branches E.g. banyan tree

-stilt roots : arise from lower nodes of the stem E.g. maize, sugar cane

-respiration: in plants living in swampy areas root grow vertically upwards and help to get O2 E.g. pneumatophores - rhizophora

LEAF

- In some leguminous plants the leaf base may be swollen and is called pulvinus .

- The arrangement of veins and veinlet's in the lamina of leaf is known as venation.

-when the veinlet's form a network the venation is termed as reticulate

- when the veins run parallel to the lamina the venation is termed as parallel.

- dicot plants reticulate venation and monocot plants parallel venation.

-simple leaves: a leaf having a single or undivided lamina

compound leaves : when the divisions of the leaf touch the midrib

pinnate: feather like outline bear leaves on the common rachis and leaflets occur in two lateral rows

palmate: palm like outline the leaflet joining point represents tip of the petiole and all leaflets are clustered together.

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	Created by amita sherine over 9 years ago

11 biology Note on morphology of plants , created by amita sherine on 21/12/2014.