Which of the following processes is involved in the cooling effect of plants during transpiration?

The cooling effect of plants during transpiration is primarily caused by evaporation. When water is absorbed by a plant's roots, it moves up through the plant to the leaves, where it is eventually released into the atmosphere as water vapor. This process involves the conversion of liquid water into vapor, which requires energy in the form of heat.

As water evaporates from the leaf surfaces, it takes heat energy with it, thus cooling the plant. This mechanism is crucial, especially during hot weather or in environments where plants are exposed to intense sunlight, as it helps to maintain optimal temperatures within the plant tissue. The cooling effect beneficially influences physiological processes, minimizing heat stress and promoting overall plant health.

While capillary action plays a role in the movement of water within the plant, it does not directly contribute to cooling. Photosynthesis is the process by which plants convert light energy into chemical energy, and while it can indirectly affect transpiration rates, it is not involved in the cooling effect itself. Absorption refers to the uptake of water and nutrients but does not pertain to the cooling process either. Hence, the cooling effect during transpiration is primarily linked to evaporation.