The process of transpiration is as follows: water root hairs in soil → root ducts → stem ducts → leaf ducts → stomata → atmosphere.
The physiological significance of transpiration has the following three points:
(1) Transpiration is the main driving force for plants to absorb and transport water.
(2) Mineral salts (inorganic salts) can only be absorbed by plants and run in the body if they are dissolved in water. Because transpiration is the driving force of water absorption and flow, minerals are also absorbed and distributed in various parts of plants with the absorption and flow of water. Therefore, transpiration contributes to the transport of these two substances in plants.
(3) Transpiration can reduce the temperature of leaves.
Several factors affecting evaporation:
(1) illumination: illumination promotes stomatal opening and increases transpiration.
(2) Water condition: Sufficient water is beneficial to stomata opening, while excessive water makes stomata closing.
(3) Temperature: Generally, the stomatal opening increases with the increase of temperature, but the stomatal opening can also be closed due to the increase of water loss at higher temperature.
(4) Wind: Breeze is beneficial to transpiration, while strong wind reduces transpiration.
(5)CO2 concentration: Low CO2 concentration promotes stomatal opening and transpiration enhancement.
The question behind you is to examine the second role and the second influencing factor. Because there is too much water, the stomata are closed to reduce transpiration, and the water transport in crops is slow, so the transport of inorganic salts is also reduced, so C should be chosen for calcium deficiency.