(a) Arithmetic growth, If the length of a plant organ is plotted against time shown a linear curve, the growth is called arithmetic growth.
(b) Geometric growth. Such type of growth, that occurs in many higher plants and plant organss and measured in size or weight, is called geometric growth.
(c) Sigmoid growth curve. If the geometrical growth is plotted against time, it shows a sigmoid growth curve.
(d) Absolute and relative growth rates. Increase in total of two organs measured and compared per unit time is called absolute growth rate. The growth of the given system per unit time expressed on a common basis is called relative growth rate.
