Plant growth regulators and their role in plant growth with special reference to mulberry

Plant growth regulators are organic compounds synthesized in specified plant parts in small quantities and are transported to the place of requirement leading to a change in physiological responses. They can be classified into growth promoters and growth retardants. Plant growth promoters are auxin, gibberellin, cytokinin and growth retardants include abscisic acid and ethylene. The latest growth promoter brassinosteroid, translocates nitrogen and phosphorus. Triacontanol is one of the commercial formulations used to increase the moisture and protein content in mulberry leaves, which ultimately build disease resistance in silkworm. Plant growth promoting rhizobacteria stimulate the plant growth regulators like auxins, gibberellins etc. and help in better nutrient uptake and increase tolerance.