In what different ways are leaves designed to get rid of excess water?

Question

Describe the path of a molecule of water in detail as it is absorbed from the ground through the leaves of a tree into the atmosphere

Answer 1

Two ways i.e. Transpiration and Guttation
Transpiration:
Transpiration can take place through the exposed surface of cell walls but the greatest amount takes place through the stomates. These are specialized guard cells that control the size of tiny pores, stomata, for gas exchange and the release of water vapor.

We have the movement of moisture or sap from the roots to the leaves. This movement supplies the food-manufacturing cells with water needed for photosynthesis and to provide the moisture necessary for the dispersing of carbon dioxide into and oxygen out of these cells.

Various factors influence the transpiration rate. Photosynthesis, induced by light, has the effect of increasing the water pressure in the cells that border each stomate. The widening of the stomate increases water loss.

Low humidity promotes the dispersing of water vapor from the air passages inside the leaf into the outside air. A lack of water in the soil cuts down the water supply to the cells, thus limiting expansion of the cells.

Therefore the transpiration is highest on a bright, dry day and lowest at night or in drought conditions. It all gets down to the fact that the plant must get rid of the excess water in the leaves.

Guttation:
When leaves lose water as a liquid phase through special cells called hydathodes it is referred to as guttation.

These guttation "tears" appear at the leaf tips or margins and contain various salts, sugars and other organic substances.

This action can also lead to the penetration of unwanted bacteria that can cause plant disease problems. The use of some leaf cleaners and leaf shines can also plug up the hydathodes and cause browning tips.