Question

Go through the four statements given beIow:
I. Root pressure provides a light push in the overall process of water transport.
II. Most plants meet their water need by transpiration pull.
III. The greatest contribution of root pressure may be to re-establish the continuous chains of water molecule in the xylem vessel which often break under enormous tension created by transpiration.
IV. Guttation is the cause of transpiration pull.

The correct statements are

• A. I, II, 111, IV
• B. I, II, Ill
• C. II, Ill, IV
• D. II, Ill

Answer 1

The correct option is B I, II, Ill

At night and early morning when evaporation is low, excess water collects in the form of droplets around special openings of veins near the tip of grass blades, and leaves of many herbaceous plants. Such water loss in its liquid state is known as guttation.

Root pressure can, at best, only provide a modest push in the overall process of water transport. Guttation does not play a major role in water movement up tall trees.

The greatest contribution of root pressure may be to re-establish the continuous chains of water molecules in the xylem which often break under the enormous tensions created by transpiration.

Root pressure does not account for the majority of water transport; most plants meet their need by transpiratory pull.