Question

transpiration in plants takes place at day time very rapidly which creates a suction pull in xylem vessels but what happens at night?

Answer 1

Transpiration is a process by which plant release excess water into the atmosphere from the leaves and stems through stomata during daytime. It occurs in the presence of sunlight during day time and so the stomata also open. But stomatal pores are closed during night and hence, transpiration process will not takes place and so no suction pull in xylem vessels occur. Instead Guttation occurs at night as water loss through transpiration is very less due to less transpiration rate at night. Guttation is the release of drops of xylem sap on the edges of leaves. It happens due to root pressure which absorbs excess water and send it to the leaves. The leaves can't withstand so much of water pressure and excrete some of them in form of droplets. Here water loss is not pure and hence contains inorganic and organic substances.