1. The young cells absorb water by imbibition.
2. The germinating seeds imbibe water resulting in the bursting of seed coat leading to their germination.
3. Roots absorb water by imbibition initially.
4. The imbibitional pressure helps the roots and seeds to push through the soil.
Turgor pressure : It is the pressure exerted by protoplast upon the cell membrane of cell wall.
Imbibant : It is the solid substance which absorbs water and swells up.
Imbibate : It is the liquid or water which is imbibed by the imbibant.
Imbibition pressure : The imbibant, after imbibition of water or liquid, exerts the pressure which is called imbibition pressure. The germinating seeds have imbibition pressure of about 1000 atmospheres.
Osmosis is of two types :
(a) Exosmosis (b) Endosmosis.
(a) Exosmosis : It is the process by which solvent molecules diffuse from inside to outside across a semipermeable membrane.
(b) Endosmosis : It is the process by which solvent molecules diffuse from outside to inside of a cell across a semi-permeable membrane.
The diffusion pressure of pure water is maximum and it continues to decrease as more and more solute is added into it.
D.P.D = O.P - T.P
Where,
D.P.D. = Diffusion pressure deficit
O.P = Osmotic pressure
T.P = Turgor pressure
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