ICSE Class 10 Answered

Osmotic Pressure

• Osmotic pressure is the minimum pressure that must be exerted to prevent the passage of the pure solvent into the solution when the two are separated by a semi-permeable membrane.
• It can also be defined as a measure of tendency of a solution to take in water by osmosis.
• Plant cells exhibit a considerable range of variations in osmotic pressure.
• In land plants, osmotic pressure varies from 5 to 30 atms, while in aquatic plants, it varies from 1 to 3 atms. Plants of arid regions possess the highest osmotic pressure.

Factors Affecting Osmotic Pressure

• Concentration of solute particles
• Ionisation of solute molecules
• Temperature
• Hydration

Importance of Osmotic Pressure in Plants

• Leaves become turgid and expand because of their osmotic pressure.
• Resistance of plants to drought and frost is brought about by osmotic pressure of their cells.