Classification of plant nutrients based on chemical behavior and physiological functions :
Mechanism of Mineral uptake by Plants
Previously, it was thought that the absorption of mineral salts from the soil took place along with the absorption of water, but it is now well established that the mineral salt absorption and water absorption are two independent processes. 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 tips. The plasma membrane of the root cells is not permeable to all the ions. It is selectively permeable. All the ions of the same salt are not absorbed in an equal rate but there is unequal absorption of ions. The first step in the absorption of mineral salts is by Ion Exchange. Once the nutrients come and adsorb on the surface of the walls of the membranes of root cells, then the further process of the absorption of mineral salts may be of two types. They are : 1. Passive Absorption 2. Active Absorption Various theories have been proposed to explain the mechanism of mineral salt absorption, which ca...
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