Question

Why do the desert plants have the layer of cutin although guard cells are there for preventing water loss by transpiration?

Answer 1

Dear Student,
Desert plants have a thick waxy covering of cutin on their surface. This is due to the following reasons:
1. This layer is not permeable to water, hence prevents excessive Transpiration.
2. It protects the plants against the intense sunlight.
3. It is also found that this waxy coating reflects sunlight, thereby reducing the plant temperature by a few degrees.
Hence, the guard cells close in order to prevent water loss by Transpiration, but, the waxy covering plays an important role too.