Uptake of minerals, Active and passive uptake of minerals, Donnan’s equilibrium, Cytochrome pump mechanism and carrier hypothesis, role of calmodulin
Mineral Absorption ( Uptake of Minerals ):- · Pathway:- Uptake of minerals takes place through apoplast as well as symplast pathway. · Mineral salts are translocated through xylem along with the ascending stream of water. · Mineral salts are absorbed from the soil solution in the form of ions. They are chiefly absorbed through the meristematic regions of the roots near the tips. · Plasma membrane of the root cells is not permeable to all the ions. It is selectively permeable. 1. Passive Absorption (Passive Uptake) :- It does not require expenditure of metabolic energy. a. Simple Diffusion:- When the concentration of mineral salts is higher in the outer solution than in the cell sap of the root cells, the mineral salts are absorbed according to the concentration gradient by simple process of diffusion. b. Ion Exchange Mechanism:- The ions adsorbed on the surface of the w...