Tips and Tricks

Basic terms used in plant water relations:

Follow up:

1.Isotonic solution: A solution with same solutes concentration as that of a specified solution.

2.  Hypotonic solution: A solution has lower solute concentration than that of a specified solution.

3.Hypertonic solution: A solution has higher solute concentration than that of a specified solution.

4.Permeable membrane: A membrane that allows both solute and solvent molecules to pass through. E.g. cell wall, filter paper, etc.

5.Impermeable membrane: A membrane that does not allow solute or solvent molecules to pass through. E.g. cuticle and suberin

6.Semi-permeable membrane: A membrane that allows only solvent molecules to pass through and not solutes.

E.g. plasma membrane, tonoplast, egg membranes, sheep and goat urinary bladder, parchment paper, etc.There is no perfect semi-permeable membrane. In addition to solvent molecules some membranes allow traces of solute molecules also to pass through, such membranes are called as Selective permeable or differentially permeable membranes.

IMBIBITION:

1.Definition:  It is a surface phenomena in which surface adsorption of water molecule by a dry solid substance without forming a solution.

2.The hydrophilic substances are called Imbibants. Examples- Cellulose, Hemi cellulose, Pectin, Gelatin,   Lignin, Resins, Gums and Starch

3.The pressure developed in the imbibants due to adsorption of water is called imbibitional pressure or matric potential.

4.Mechanism of imbibition is quite different from that of osmosis, as it does not involve the diffusion of water through a semi-permeable membrane.

Note: Adsorption means sticking to the surface. Dilatometer is used in the measurement of imbibitional  pressure.

Pages: 1 · 2 · 3 · 4 · 5 · 6