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Abscisic acid is phytohormone which acts as the seed inhibitor. The presence of abscisic acid and absence of growth promoters such as the gibberellic acid etc. also inhibits the germination. Some other inhibitory substances of seed germination such as the phenolic acids, coumarin, and short chain fatty acids are seen in the embryo, endosperm or testa. The seeds become dormant when exposed to higher temperature than the maximum temperature needed for germination. Some other seeds become dormant due to lower temperature than the minimum temperature needed for germination.