Question

What happens to the tension in the xylem when the stomata close and evaporation stops? It remains constant the moment the stomata close. It continues to increase until the living cells of the leaf are fully hydrated. It goes to zero once evaporation ceases. It drops to a value closer to that of the water-filled pores in the soil.

Answer 1

Answer:

Explanation:

What occurs when the stomata close and evaporation stops is that, the tension in the xylem continues to increase until the living cells of the leaf are fully hydrated. This happens according to the cohesion-tension theory of sap ascent.

This happens at night. Transpiration stops immediately when the stomata is closed. There is a cohesion between each water molecule and adhesion between the water molecules and the stem walls; water is held in the leaves ad stems when the stomata is closed this hereby increases the tension.