Plant Growth Regulator (PGR) is a chemical substance used to alter the growth processes of plants, such as seed germination, root development, flowering, and fruiting. PGRs can be natural or synthetic and are applied to influence plant size, shape, and development. Common uses include promoting rooting in cuttings, controlling plant height, and regulating flowering times. PGRs are widely used in agriculture, horticulture, and landscaping.