Aquaporin’s are found in both plant and animal membranes but they are relatively abundant in plants. The aquaporin’s satisfactorily account for the observed rate of water movement across the membranes which could not be explained earlier simply by direct diffusion of water through lipid bilayer as the latter does not allow bulk flow of water across it.
The texture of a soil depends upon the proportion of different sized soil particles in that soil and is a very important factor for the absorption of water in plants.
Such soils are very rich in sand particles and though well aerated they have poor water holding capacity. Sandy soils are, therefore, not good for water absorption.
Sufficient amount of water should be present in the soil in such form which can easily be absorbed by the plants. Usually the plants absorb capillary water i.e., water present in films in between soil particles. Other forms of water in the soil e.g., hygroscopic water, combined-water, gravitational water etc. are not easily available to plants. Increased amount of water in the soil beyond a certain limit results in poor aeration of the soil which retards metabolic activities of root cells like respiration and hence, the rate of water absorption is also retarded.
Earlier workers thought permanent wilting percentage to be a soil moisture constant. This view has been strongly criticised by Slatyer (1957) who pointed out that permanent wilting percentage of a soil is dependent on the osmotic characteristics of the plant and is not a soil-moisture constant. Thus the different plants if grown in the same soil wilt at different times depending upon their osmotic potential after the water supply to the soil is stopped.
(iii) Metabolic activities of root cells are decreased, and
(ii) Trans-membrane pathway (by crossing the plasma membranes) and
The percentage of the soil water left after the plant growing in that soil has permanently wilted is called as permanent wilting percentage or the wilting coefficient. The permanent wilting percentage can be determined by growing the seedlings in small containers under conditions of adequate water supply till they develop several leaves. The soil surface is then covered and the water supply is cut until wilting occurs. The containers are now transferred to humid chamber.
Following evidences support this view:
Absorption of Water in Plants (With Diagram) Let us make an in-depth study of the absorption of water in plants. After reading this article you will learn about 1. Mechanism of Absorption of