Question

Define the three processes by which plants absorb water and minerals from the soil.

Answer 1

Plants absorb water and minerals from the soil through three primary processes: osmosis, diffusion, and active transport.

1. Diffusion: The movement of molecules (gas, liquid, or solid) from a higher concentration to a lower concentration is called diffusion.
   Soil water moves into the root hairs through the process of diffusion from higher concentration to lower concentration as we put sugar in the milk, and the sugar molecules are evenly distributed in the milk and occupy intermolecular spaces.
2. Osmosis: The movement of water molecules across a semipermeable membrane from an area of higher water potential (lower solute concentration) in the soil to an area of lower water potential (higher solute concentration) inside the root cells.
   The cell sap and the cell walls act as semi-permeable membranes and permeable membranes. The concentration of the cell sap is more as compared to the water + minerals present in the soil. So the water and dissolved minerals enters the roots by the process of osmosis.
3. Active transport: The movement of molecules from their lower concentration to a higher concentration by using energy is called active transport.
   Root hairs absorb water and minerals from the soil. Water diffuses into the root hairs as the water concentration is higher than that of the root hair. However, in the case of minerals, these move from lower concentrations to molecules of higher concentration.
   The minerals from the soil, along with water, move into the roots. This is active transport in the opposite direction, which needs energy.