The growth and development of plants , the formation of different organs, etc., are caused by the influence of a special type of biochemical substance produced in the plant body. Which controls all actions. This substance is called hormone or life juice This biochemical substance in plants is called phytohormones. Some people want to refer to phytohormones as plant growth agents. The phytohormones found in plants are auxin , gibberellin , cytokinin and absolic acid.