Question

Define hygroscopic and capillary waters? Which is not available to plants and why?

Answer 1

Hint: The hygroscopic water and capillary waters are types of soil water. Soil water is also known as rhizic water because roots are known as rhizoids and water is absorbed by roots. The amount of water present in the soil which may or may not be available to plants is known as soil water. It is of four types mainly gravitational water , hygroscopic water , chemically combined water and capillary water.

Complete answer:
Now let us know about hygroscopic and capillary water
Hygroscopic water:-
Hygroscopic water is usually found as a microscopic film. it is found as water surrounding soil particles. This water remains tightly bound to a soil particle. it remains attached due to molecular attraction so powerful. it cannot be removed by natural forces.
Clay holds more amount of hygroscopic water than the sand can hold.
This water is not available to the plants.
This water is not available because this water has low water potential.
Capillary water :-
This water is present in micro pores of soil . This water is held due to the force of gravity. The capillary water is used to transport nutrients and minerals. When the soil dries the micro pores size increases due to this the force of gravity changes capillary water into gravitational water.
Capillary water is the most common water that is available to plants.

Note: Absorption of water is a biological process that is defined as uptake of capillary water and not hygroscopic water by roots hair of plant from soil to root xylem. It occurs in many ways like respiration , transpiration and osmosis. Soil water is also known as rhizic water.