the Water mode of plants. Absorption of water from soil

you are: the Water mode of plants

Almost all water absorbed by a plant arrives in it through roots; elevated parts of a plant if absorb any quantity of water, only rather insignificant. At the majority of plants the root system forms strongly branched out network deeply penetrating soil. Water and mineral substances are absorbed by cages epidermisa near to a root tip. The numerous root hairs representing vyrosty epidermalnyh of cages, get into cracks between soil particles and many times over increase absorbing surface of a root. Water is absorbed exclusively at the expense of osmotic forces, moving from sites with high f (in soil) to sites with lower f (in roots).

The Soil can be considered as a certain tank which that is filled with water, again oporazhnivaetsja. After a rain free water filters through soil and the soil is in a condition of a field moisture capacity. at a field moisture capacity f soils it is close to zero; water thus is easily taken from soil by roots of plants, and also purely mechanically - tsentrifugirovaniem or otzhimaniem. On a measure podsyhanija its soils goes down. When f soils more low, than f root cages, a plant zavjadajut because in these conditions they more cannot already absorb water from soil. Degree uvlazhnennosti the soils, corresponding to such condition, name humidity zavjadanija. In different soils humidity zavjadanija strongly varies: in coarse-grained sandy soils it happens low, and in tonkodispersnyh clay - concerning high. Distinction it is connected by that in tonkodispersnyh clay soils the area of a surface of particles is rather great, water on this surface is kept for the account sorbtsionnyh forces very strongly, and roots of plants cannot take away it from soil particles. strong salinity also reduces f soils and raises probability zavjadanija plants. Whichever there was the soil type, any kind of plants not in a condition to take from it water, if f a soil solution more low-15 a bar. Therefore though in clay soils it is kept more waters, than in sandy, in them also more waters is and in strongly connected, i.e. In inaccessible to plants, a condition.