ABSTRACT
Citrus fruits have special importance due to their distinct flavours and therapeutic value. Citrus fruits are an excellent source of vitamin C with fair amounts of vitamins A and B and minerals such as calcium, phosphorus and iron. Plant growth regulators (PGR) are synthetic analogues of naturally occurring plant hormones. Citrus is no exception to the use of PGRs, which can provide significant economic advantages to citrus growers when used appropriately. In citrus there is a positive correlation between the level of endogenous growth substances and the degree of growth and development in the developing tissues. Endogenous level of auxin plays a dominant role in leaf abscission. That is, a high level of auxin in leaf blades retards abscission, while its decrease induces abscission. Citrus trees, once pass the juvenile phase, bloom every year. Annual flowering of adult trees is affected by several exogenous and endogenous factors.
