Transpiration as a necessary evil
Transpiration is the evaporation of water from plants. It occurs chiefly through the leaves whiletheir stomata are open for the passage of carbon dioxide and oxygen during photosynthesis.
Transpiration also occurs through the cuticle and lenticels. Lenticels are pores in the stems ofwoody plants that allow gaseous exchange between the atmosphere and the internal tissues.Transpiration is a necessary evil because of the following facts:-
1. A large amount of absorbed water is lost during transpiration which is harmful to plants.
2. Unnecessary wastage of energy takes place during the process of water absorption which islost due to transpiration.
3. When the rate of transpiration is high in plants growing in soil deficient in water, an internalwater deficit develops in plants which may affect metabolic process.
4. Many xerophytes undergo structural modifications and adaptations to check transpiration.