Question

Consider the following statements:
Assertion (A): Water uptake by root hairs from soil occurs through osmosis
Reason (R): Casparian strips in endodermis are suberized

• A. Both (A) and (R) are true, (R) is the correct explanation of (A)
• B. Both (A) and (R) are true, (R) is not the correct explanation of (A)
• C. (A) is true, but (R) is false
• D. (A) is false, but (R) is true

Hint:

Osmosis at root hairs depends on water potential gradient. Casparian strips prevent uncontrolled apoplastic flow, ensuring selective absorption. Distinguish between cause (osmosis) and regulation (Casparian strip) in exams.

Answer 1

The Correct Option is B

Water is absorbed by root hairs from the soil via osmosis due to water potential difference. Casparian strips in the endodermis are suberized to block apoplastic movement and force water to move symplastically. While both statements are true, Casparian strips do not directly cause water uptake by root hairs; they regulate water movement inside the root. Hence, option 2 is correct.