An autoradiographic study of the effect of the plant hormone abscisic acid on nucleic acid and protein metabolism.

Abscisic acid maintains embryos in a state of dormancy and inhibits the incorporation of H(3)uridine and H(3)thymidine but not the incorporation of H(3)leucine. Ribosomes present in imbibed but dormant embryos do not become associated into polysomes until actual germination of the embryos. Protein synthesis still occurs in embryos when RNA synthesis is inhibited and therefore stable m-RNA must be present in dormant embryos. It is concluded that abscisic acid maintains dormancy by inhibiting the production of specific types of m-RNA, and therefore the formation of specific proteins. The activity of abscisic acid is antagonistic to the effect of gibberellic acid in dormancy.