Plant growth regulators (also called plant hormones) are numerous chemical substances that profoundly influence the growth and differentiation of plant cells, tissues and organs. They are used to regulate the growth of plants and are important measures to ensure agricultural production. Plant growth regulators function as chemical messengers for intercellular communication . There are currently five recognized groups of plant hormones: auxins, gibberellins acids (GA3), cytokinins, abscisic acid (ABA) and ethylene. Plant growth regulators will not be hazardous to human health if they are used in accordance with good agricultural practice.