What are the different phases of growth in plants? Give characteristics of each.

Growth may be defined as an irreversible increase in the number and size of a cell, organ or whole organism.

The growth in plants involves three phases, viz. meristematic, elongation and maturation.

(1) Meristematic Phase (Formative Phase)

The meristematic phase consists of the constantly dividing cells of the root apex and the shoot apex. The cells of meristematic region are rich in protoplasm and possess large nuclei. The cell walls of these cells are primary in nature, thin and cellulosic with abundant plasmodesmatal connections.

(2) Elongation Phase

The cells which are in proximity to the meristematic zone represent the phase of elongation. In this phase, there is increased vacuolation, cell enlargement and new cell wall deposition. Cell enlargement may be linear or in all directions.

(3) Maturation Phase

The maturation zone lies next to the phase of elongation. The cells of this zone attain their maximal size in terms of wall thickening and protoplasmic modifications. These cells form different kinds of simple and complex tissues which perform different functions.