Which of the following is not a xerophytic adaptation to reduce transpiration ?

Question

Accepted Answer

Option 3, "Presence of keratin layer on the leaf surface," is the correct answer because keratin is a protein primarily found in animals, particularly in hair, nails, and skin. It is not a component typically found in plant structures. Therefore, the presence of a keratin layer on the leaf surface is not a recognized xerophytic adaptation for reducing transpiration in plants.

Now, let's examine why the other options are incorrect in the context of xerophytic adaptations:

1. **Stems take over the function of photosynthesis**: In many xerophytic plants, such as cacti, the leaves are reduced or absent to minimize water loss, and the stems become green and take over the function of photosynthesis. This adaptation helps reduce transpiration by minimizing the surface area exposed to the environment.

2. **Presence of hairs in stomatal pits**: This is a common xerophytic adaptation. The presence of hairs in stomatal pits helps trap moisture and reduce air movement around the stomata, thereby reducing water loss through transpiration.

3. **Presence of waxy coating on leaf surface**: A waxy coating, or cuticle, on the leaf surface is a well-known adaptation in xerophytes. It acts as a barrier to water loss by reducing evaporation from the leaf surface.

In summary, Option 3 is correct because keratin is not a plant adaptation for reducing transpiration, whereas the other options describe well-established xerophytic adaptations that help minimize water loss in arid environments.