Long water deficiency reduces intensity of photosynthesis and, as a result, reduces formation of ATR in the course of photosynthetic phosphorylation. Under the influence of a soil and atmospheric drought also outflow of products of photosynthesis from leaves in other bodies is slowed down.
Negative effect of a water stress during vegetation consists in suppression of growth processes as the most difficult and demanding coordination between separate physiological functions. Owing to suppression of growth the area of leaves is reduced, i.e. the assimilating surface, as is the main reason for decrease in crops at a drought.
Influence of water deficiency on a carbohydrate exchange is expressed in decrease in the contents mono in the beginning - and bioses in photosynthesizing leaves because of decrease in intensity of photosynthesis, then the quantity of monosaccharides can increase as a result of hydrolysis of polysaccharides of leaves of the lower circles. At long water deficiency reduction of quantity of all forms of Sugars is observed.
Protoplasm of the majority of plants is extremely sensitive to dehydration. Cages of elevated bodies of mezofit to which the majority of crops belongs, perish if their some hours to keep in air with relative humidity 92 — 96% that corresponds to a depression of the water potential of 5,5 — 11 MPas. Roots are even more sensitive. Water deficiency leads to the progressing protoplasm dehydration that causes violation of physiological functions, their termination and damage of protoplasmatic structures. The decrease in the content of water in a cage below an optimum level causing violations of a metabolism is called as a water stress.
It is known that oxygen of air is not an active oxidizer as both valencies of oxygen mutually sate each other: O=O. In order that oxygen could be an active oxidizer, it has to be at first made active, i.e. the molecule with communications of this sort has to turn out: — About — About —.
clarifications of components of water balance of plants and development of methods of more productive use of rainfall, irrigating water, introduction of a drop and pulse irrigation, the automated irrigating systems;
Deficiency of moisture in plants affects such processes as water absorption, root pressure, germination of seeds, the oyster movements, a transpiration, photosynthesis, breath, fermentativny activity of plants, growth and development, a ratio of mineral substances, etc. Changing a metabolism, the lack of water influences efficiency, taste of fruits, wood density, length and durability of fiber at a cotton etc. The ovodnennost degree necessary to start germination of seeds, strongly varies at different types. Between the speed of germination of seeds and speed of absorption of water there is a certain correlation. The speed of germination is influenced also by properties of seeds and water-retaining ability of the soil.