Question

Assertion (A): Plant roots absorb water from soil colloids.

Reason (R): Hygroscopic water is held by soil colloids.

Options

• Both A and R are true and R is the correct explanation of A.

• Both A and R are true but R is not the correct explanation of A.

• A is true but R is false.

• A is false but R is true.

Answer 1

A is false but R is true.

Explanation:

The assertion is false because plant roots cannot absorb water from soil colloids; they primarily absorb capillary water, which is the only form of soil water easily available to plants. The reason is true because hygroscopic water is indeed tightly held as a thin film on the surface of soil colloids by strong adhesive forces. Because these forces are too powerful for root hairs to overcome, this specific water remains completely unavailable to the plant.