Gibberellins in Immature Seeds of Pharbitis nil

Part I. Isolation and Structure of a Novel Gibberellin, Gibberellin A₂₀

抄録

A new gibberellin, gibberellin A₂₀ (GA₂₀), was isolated from immature seeds of morning-glory (Pharbitis nil). Its structure was established as 4aα, 7α-dihydroxy-lβ-methyl-8-methylenegibbane-lα, 10β-dicarboxylie acid-1→4a lactone (I) on the basis of its physico-chemical analysis as well as chemical evidences. GA₂₀ shows marked growth promoting activities on dwarf maize d₂ and d₅ but weak activities on d₁, rice seedling and dwarf pea.