During a period of severe drought, a plant prevents excessive transpiration by closing its stomata. Which hormone acts as the primary stress signal?
Q1. During a period of severe drought, a plant prevents excessive transpiration by closing its stomata. Which hormone acts as the primary stress signal?
Answer: Abscisic acid
Explanation: Abscisic acid promotes stomatal closure during water stress; Cytokinins fail as they generally promote cell division and delay leaf senescence.