Question

Assertion :When the ambient temperature is high and soil contains excess of water, the plants tend to lose water in the form of droplets from lenticels. Reason: Root pressure regulates the rate of loss of water form lenticels.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Both Assertion and Reason are incorrect.

Answer 1

The correct option is D Both Assertion and Reason are incorrect.

Loss of water in form of droplets from leaf margins or hydathodes under conditions of high soil moisture, high humidity, higher water absorption by roots and lower transpiration rate is known as guttation. Lenticles exhibit normal transpiration (loss of water in form of water vapour).
When soil moisture is high, movement of water and dissolved minerals from soil into root hair and finally to the root xylem cells build up root pressure which in turn pushes the water up the xylem vessels. The increased soil moisture and the high root pressure causes increased rate of water absorption which in turn forces water droplets to come out from hydathodes. Lenticular and stomatal transpiration creates transpiration pull which in turn carry the water and minerals up in stem thereby decreasing root pressure.
Therefore, the correct answer is option D.