Plant Hormones or Phytohormones, Biology, Class 10 ,Science

The control and coordination in plants is done by plant hormones (or phytohormones). The plant hormones coordinate the activities of the plant by controlling one or the other aspect of the growth of the plant. So, the plant hormones are also known as plant growth substances. The growth of a plant can be divided into three stages : cell division, cell enlargement and cell differentiation (or cell specialisation), and these stages have particular locations in a plant. These three stages of plant growth as well as promotion of dormancy, breaking of dormancy, stomata control, falling of leaves, fruit growth, ripening of fruits and ageing in plants are controlled by the various plant hormones.

There are four major types of plant hormones (or phytohormones)

which are involved in the control and coordination in plants. These are :

Auxins,

Gibberellins,

Cytokinins, and

Abscisic acid (ABA).

Auxins, gibberellins and cytokinins are the plant hormones which promote growth of plants. On the other hand, abscisic acid is a plant hormone which inhibits (or prevents) the growth.