Physiology of Seed Dormancy and Germination-A Review

Seed dormancy is considered as an inherent property which outlines the environmental conditions in which the seed is accomplished to evolve. To better understand seed dormancy mechanisms, a series of rigorous studies examining seed metabolism in relation to gibberellin and abscisic acid have been organised. Abscisic acid is a hormone involved in the formation of primary dormancy, whereas gibberellins are a hormone involved in the induction of germination. During changes in dormancy certain variations in sensitivity can be observed. In the higher plants as the dormancy is present across all climatic regions differing responses in the environment has resulted due to adaptation. As a result of this variance, incubation is timed to avoid adverse weather conditions in order to promote reproductive growth and plant establishment. All molecular mechanisms emphasizing kernel latency initiation, conservation and improvement play a large part in the evolution and adaptation of these seeds and plants and their importance is indescribable. Together genetic and environmental factors are liable for triggering seed dormancy. For the induction of seed dormancy and besides its release the balance between the intensity of ABA plus GA remain in charge. There is a triphasic pattern of germination including imbibition i.e rapid uptake of water, enzyme activation and initiation of embryo growth resulting in the radicle protrusion. The dormancy state is regulated not only by the seed maturation environment, but it also changes over time after shedding in a way that is determined by the ambient environment.