Short answerEasy1 mark
3(iv)
Two well-watered, identical plants were placed in brightly lit rooms at different temperatures — one at 15°C and the other at 38°C. The plant in the warmer room showed wilting by the end of the day.
Which plant phenomenon resulted in the wilting of the leaves?
Topic: Transpiration
Previous-year question practice database
Answer
Exam answer
TRANSPIRATION.
Explanation
Transpiration is the loss of water as vapour from the aerial parts of a plant, mainly through the stomata. At 38°C it is far more rapid than at 15°C, because heat increases the rate of evaporation from the mesophyll cell surfaces.
WILTING occurs when water is lost faster than the roots can absorb it. The cells lose their turgor, become flaccid, and can no longer hold the leaf rigid — so it droops.
More from Transpiration
Assertion (A): A thick cuticle reduces transpiration by acting as a barrier.
Reason (R): Desert plants have large, thin leaves for transpiration.2026Mention the factor of the phenomenon that is being tested.2026A waxy layer on the upper epidermis of leaves meant to reduce Transpiration.2025Regulation of the opening and closing of stomata.2025Given below is a picture of a tree. Mention the scientific phenomena occurring in the parts labelled (a), (b) and (c).2025Where are Hydathodes located?2025