Organisms And Their Environments

Tuberous root is the modification of tap root, in which it is thicketheed except at the base without producing definite shape, eg, Ipomoea batatas, Mirabilis jalapa. They are meant for storage of food.
In Beta vulgaris, the type of root present are napiform roots. It is like a top or sphere that thins abruptly at the apex. In it the swollen part is formed jointly by hypocotyl and tap root.
In Daucus carota, the tap root is like a cone being thickest towards the base and gradually tapering towards apex. Many thread like secondary roots are found throughout the length of conical fleshy root.
In Raphanus sativus, the root is in the form of spindle being thickest in the middle and narrowing towards both-apex and base.

Some organisms are tolerant of a wide range of salinities, these are called euryhaline. On the other hand, organisms which are restricted to a narrow range of salinity are called stenohaline.