One of the characteristic life phenomenons of the plants is the continuous increase in size. Besides, development of new organs takes place at least during some stages of their life time.
The term growth is employed to designate this complex process which depends on all physiological processes. Growth involves three distinct phases. Formation of new cells by the process of mitosis, then, the enlargement of the newly formed cells and lastly, differentiation or maturation of these enlarging cells into mature e tissues of a growing organ.
These processes are respectively called cell formation, cell enlargement and cell differentiation.
Growth may be considered the net result of anabolic activities over catabolic processes. Anabolic activities result in an increase in protoplasm, whereas catabolic processes simultaneously bring about a decrease in organic protoplasmic components.
As long as, anabolism proceeds in excess of catabolism, the synthesis of protoplasm and of cell wall materials outweigh their destruction and growth occurs.
Measurement of Growth in Plants
Rate of growth can be measured by various ways. Any one of the following measures can be suitably applied in determining growth rate and total growth of the individual organs of a plant or the entire plant.
(a) Increase in weight (b) Increase in volume (c) Increase in height (d) Increase in the number of cells produced.
The standard instruments like auxanometer can be conviniently used to measure the rate of growth. The criterion used by this instrument is to measure the growth by increase in length. The increase in size per unit time is referred to as relative
Be accompanied by an increase in weight or cell number. It may occur only due to cell elongation. Therefore, RGR is commonly measured in terms of increase in dry weight.