| TERMS | .. . |
| DEFINITIONS | |
| Diffusion | The movement of molecules from higher
– concentrationto lowerconcentrationis called |
| Chemical
potential . |
The total kinetic energy of the molecules is called chemical potential.• |
| Graham’s law | It states thatthe rates of diffusionof gases ai.
inverselyproportional to the square roots of the .r |
| Diffusion pressure | The pressure exerted by the diffusing particles is known as diffusion pressure. |
| Imbibition | The special type of diffusion in which an imbibant absorbs water on its surface without dissolving in it is called imbibition. |
| Imbibition pressure | The force generatedby theimbibantsis called
imbibition pressure or metric potential. |
| Osmosis | The movement of solvent molecules front the regiQn |
| of higher concentration to the region of lower
concentration through semi permeable membrane is called osmosis. |
|
| Osmotic pressure | The maximum pressure that develops when a
solution is separated from its solvent by a semi |
| Water potential | The chemical potential of water is called water
potential. The total kinetic energy of the molecules is called water potential. |
| Solute potential :-. | The decrease in water potential due to dissolution of
solute molecules or ions in water is called solute . . |
| Matric potential | The decrease in the water potential due to affinity of
water molecules with the colloidal substances (protoplasm and cell wall) is called matric potential. |
| Pressure potential | The turcor pressure (TP) exerted by the vacuole is called pressure potential. |
| Soil | [he complex composite mass made up of both inorganic and organic. components containing water and air is called soil. |
| Soil texture | Relative proportion of the soil particles size is
known as soil texture. |
| Run away water | Some of the water drains away along the slopes
after a lieu\ v rainfall. or irrigation. This is called run-a um u ater. |
| Field capacity of soil | .1-he amount of 11 at e r retained by soil after the
removal of excess water by gravitation is called ths. field capacity or the water holding capacity of the soil. |
| Ilygroscopic water_ . | Water adsorbed on the surface of soil colloids is called hygroscopic water. |
| Capillary water | The ‘sater which fills the spaces between the non
colloidal smallersoil particles is called capillary |
| Water table | The water level at some depth from the soil where all pore spaces are filled with water is called Water table. |
| Wilting coefficient | The amount. of moisture left in the soil after a plant has permanently wilt is called wilting coefficient. |
| Apoplast pathway | The movement of water molecules through the adjacent cell walls is called apoplast pathway. |
| Symplast pathway | The movement of water through the protoplast of the plant cells is called symplast pathway. |
| Root pressure | The hydrostatic pressure generated in the root which forces the water upward in the stem is called root pressure. |
| Capillary tube | A glass tube with a narrow bore is called a capillary tube. |
| Cohesion tension theory | This theory states that the negative pressure or pull or suction is created in the leaves as a result of transpiration pulls the water upward. |
| Adhesion | The attraction between the water molecules and the cell wall of the xylem cells is called adhesion. |
| Transpiration | The evaporation of water from the aerial part of plant is called transpiration. |
| Saturation deficit | Saturation deficit is the difference between the
amount of water vapour actually present in the air and the amount necessary to completely saturate it. |
| Absolute humidity | The amount of moisture actually present in the air is called its absolute humidity |
| Relative humidity | The percentage of the amount of moisture necessary for saturation at a particular temperature is called relative humidity. |
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