Various types of transport mechanisms



Various types of transport mechanisms are needed to fulfil the mineral requirements of a plant.
Why are they not fulfilled by diffusion alone?


The organic solutes in plants have to move in various directions. For example, The food substances synthesised in the leaves are translocated downwards towards the stem and roots, Similarly, the upward movement of solutes from the leaves to the developing buds, flowers and fruits take place. The food materials or minerals are also translocated radially from the cells of pith to those of cortex and epidermis. Thus, the various processes such as active diffusion, electrochemical potential and mass flow, etc., are needed in addition for the transport of minerals and organic solutes.