TRANSPORTATION IN PLANTS
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INTRODUCTION
In flowering plant a complex movement of material takes place in all directions. This is despite the facts that plants do notbear any circulatory in plants . Water is thus , taken up by the roots and reaches all parts of plans, up to the tip of the growing stem.
In plants, material also move over short distances i,e ; insde cells, accross the membrane and even cell to cell. The substances transported are water ,minerals, nutrients, organic nutrients and plant growth regulators. over short distances the substances move by diffussion and cytoplasmic streaming supplemented by active transport while the long distance transport takes place through xylem and phloem and is called translocation.
MEANS OF TRANSPORT
In rooted plants, water and minerals transport in xylem is unidirectional (i;e only from roots and stems) However , translocation of organic and inorganic nutrients is multidirectional. oranic compound synthesised in the leaves are transported to all parts including the storage organs.
PLANT WATER RELATIONS
Important nutrients are also withdrawn from plant parts undergoing sentences and are supplied to the growing parts. Harmones and plants growth regulators are present in very minute quantities and are transporated in a polarised (unidirectional )manner.
DIFFUSION
It is a physical process in which different solvent molecules or solvent molecules or solute ions are transported passively without the expenditure of energy. It is slow process , and is independent of living system. During this process, the molecules or ions flow in a random fashion from the region of higher concentration to region of lower concentration to region of lower concentration (be it a gas , liquid , or solids )
Rate of diffusion is mainly affected by the following factors:-
(1). concentration gradient of diffusing substances.
(2). permeability of the membrane separating them.
(3). Temperature
(4). Pressure
(5). Density
figure of faciliated diffusion
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