Senescence is the process of ageing which is caused by increased entropy, cellular breakdown, reduced anabolic process and increased catabolic process. Cytokinins are amino purine derivatives which promotes cell division and delay senescence by controlling protein synthesis. Auxins are plant hormones like IAA which promotes cell enlargement and responsible for apical dominance. Gibberellins are plant hormones which induces flowering in long-day plants under short day conditions. Ethylene is a gaseous plant hormone, which is responsible for fruit ripening.