Why does plants in drought stress have fewer leaves

Answer 1

Plants experiencing drought stress have fewer leaves due to a variety of adaptive responses. During a drought, plants face a shortage of water, which affects their ability to photosynthesize and maintain their normal metabolic processes. As a result, they undergo certain physiological and morphological changes to minimize water loss and survive the adverse conditions.

1. Reduced water availability: In a drought, the soil becomes dry, leading to limited water uptake by the roots. As the water content decreases, plants respond by reducing leaf production to minimize water loss through transpiration. Fewer leaves mean a smaller surface area exposed to the atmosphere, reducing the chances of dehydration.

2. Stomatal closure: Stomata are small openings present on the surface of leaves that allow for gas exchange and water vapor loss. When facing drought stress, plants close their stomata to prevent excessive water loss through transpiration. This closure reduces the exchange of carbon dioxide, limiting the availability of raw material for photosynthesis. Consequently, plants reduce their leaf production to match the reduced carbon dioxide intake.

3. Preserving water to vital plant parts: During drought stress, plants prioritize water allocation to essential organs, such as roots and stems, to maintain their survival. This water reallocation means that fewer resources are available for leaf tissue development, resulting in reduced leaf production.

4. Prioritizing energy allocation: In times of limited water availability, plants redirect their energy towards essential functions like maintaining metabolism, growth, and reproduction. The growth of new leaves requires significant energy and resources, which the plant conserves by producing fewer leaves.

Overall, the reduced leaf production in plants experiencing drought stress is an adaptive response aimed at minimizing water loss, allocating resources to vital plant parts, and conserving energy for essential functions, facilitating survival in unfavorable conditions.