Question

Process by which water enters in the roots due to diffusion, is termed as

• A. osmosis
• B. passive absorption
• C. endocytosis
• D. active absorption.

Answer 1

Answer: (B)

passive absorption

Answer 2

Water is absorbed from soil by root system and mainly by root tips. There are two independent mechanisms of water absorption in plants active water absorption and passive water absorption. In active water aborption water is absorbed by the activity of the root itself. In passive water absorption transpiration pull is responsible for absorption of water. According to this theory loss of water from mesophyll cells of leaves in transpiration decreases their T.P. and hence increases their D.P.D. or S.P. As a result of their increased DPD, they absorb water from adjacent xylem vessels of leaves. This xylem of the leaves is in continuation with xylem of stem and roots and hence this pull is transmitted downwards. The pull or tension is removed only when water is absorbed through root hair and this is passive water absorption. Thus transpiration pull is responsible for passive water absorption.