Plant hormones are responsible for healthy plant growth.
Each hormone performs its specific functions; however, nearly all of the measurable responses of plants to heredity or environment are controlled by interaction between two or more hormones.
The control and coordination in plants is done by plant hormones (or phytohormones). Phytohormones are Organic compounds other than nutrients that regulate plant development and growth.
Plant hormones, which are active in very low concentrations, are produced in certain parts of the plants and are usually transported to other parts where they elicit specific biochemical, physiological, or morphological responses. They are also active in tissues where they are produced.
Each plant hormone evokes many different responses. Also, the effects of different hormones overlap and may be stimulatory or inhibitory. Hormone concentrations or the rates of their transport can change in response to environmental stimuli. 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. In general, hormones control plant growth and development by affecting the division, elongation, and differentiation of cells. Each hormone has multiple effects, depending on its site of action, its concentration, and the developmental stage of the plant. The commonly recognized classes of plant hormones are the auxins, gibberellins, ethylene, cytokinins and abscisic acid.