Modification of Roots – Class 11 | Chapter – 5 | Short Notes Series PDF
Modification of Roots:The root is an underground part of the plant that absorbs water and minerals from the soil and anchors the plant firmly. Let us have a detailed look at the modification of roots.
Modification of Roots
For Food Storage: Tap roots of some plants become fleshy due to storage of reserve food. The main root stores extra food whereas secondary roots are thin and are involved in absorption of minerals from the soil. The swollen roots occur in different shapes. Based on their shapes, tap roots may be classified as:
Fusiform roots: These root are thicker in the middle and tappered on both ends. In this type of roots both hypocotyl and root help in storage of food. eg. Radish.
Conical roots: These roots are thicker at their upper side and tapering at basal end. eg. Carrot.
Napiform roots:These roots become swollen and spherical at upper end and tappered like a thread at their lower end. eg. Turnip (Brassica rapa), Sugarbeet
Tuberous roots: Such roots do not have regular shape and get swollen & fleshy at any portion of roots. eg. Mirabilis.
Nodulated Roots:Nodules are formed on branches of roots by nitrogen fixing bacteria, (Rhizobium). eg. Plants of leguminosae family (Papilionatae) – Pea.
For better Respiration: Halophyte or mangrove grow in oxygen deficient marshy area. Some branches of tap root in these plant grow vertically & comes out from soil. These roots are called pneumatophores through which air entered inside the plant. eg. Rhizophora, Heritiera, Sonaratia and other mangrove plant.