Modification of Root
1. Roots for storage
Look at a radish, turnip, beet root, and carrot. They all grow under the soil. As soon as you pluck it from the ground if you wash them gently, you will notice small roots dangling from their surface. All these vegetables are in fact roots of the plant. Instead of thin slender roots, in case of such plants, the roots have become a place to store the food produced by them.
Hence they are thick and swollen.
One can notice that the tap root of radish is in the shape of spindle, swollen
in the middle and tapering at both ends. Such type of modified roots are called
spindle shaped root. Example : Radish
At times, like in the case of
turnip, and beet root the tap root can acquire a shape of top, that is
spherical at the base and tapering shortly towards the apex. They are called as
Top shaped root.
In case of carrot, the shape
is conical, broad at the apex and tapering gradually towards the base and such
modified roots are called Conical shaped root.
ACTIVITY 5
Aim: To study the modification of root.
Materials Required: Sample / charts of raddish, carrot, beet
root, sweet potato, stilt roots and pneumatophores.
Procedure: Carefully observe the shape of each specimen.
Observation: Draw the diagram and observe the morphological differences
between the samples.
2. Mechanical Support
Look at a banyan tree. It seems to
have many trunk supporting it. However many of them are actually roots. As the
banyan tree is large and huge, it needs support not to tilt and fall down. Many
plants require such additional support. Such plants develop roots on their
aerial parts to provide mechanical support. These roots grow downward and act
as supportive organs. There are three types of modified roots for support.
i. Prop roots: Roots are modified to provide mechanical support as
seen in Banyan tree. These roots grow vertically from horizontal branches of a
tree.
ii.
Stilt roots : In sugar cane, and
maize adventitious roots arise from the nodes in cluster at the base of the
stem. These roots are called stilt roots which gives additional support.
iii. Climbing roots: In betel and black
pepper, nodes or intermodes bear roots which help in climbing.
A root growing from a
location other than the
underground, such as from a stem or leaf is called as
adventitious root
3. Gaseous Exchange:
Avicennia
is a tree which grows in mangroves or swamps. They have roots which are seen
above the ground for the purpose of gaseous exchange. These roots are erect,
peg like structures
with numerous pores through which air circulates. These roots are called breathingroots,
or pneumatophores.
Vanda is an epiphytic plant, which grows on trees. Thevelamen
tissue present in the epiphytic root, absorbs moisture,to perform
photosynthesis
4. Roots for other vital function
Roots may also be perform special
function. Haustoria or Sucking roots, are one such example. Cuscuta a
parasite plant, climb the trees and other vegetation and use the haustorial
roots to penetrate the tissue of the host plant and suck nutrients from them.
They are usually found in parasitic plants that depend on the host plants for
nutrients.
Related Topics
Privacy Policy, Terms and Conditions, DMCA Policy and Compliant
Copyright © 2018-2023 BrainKart.com; All Rights Reserved. Developed by Therithal info, Chennai.