Use of an Acylcyclohexanedione Growth Retardant LAB 198 999 to Determine Whether Gibberellin A20 Has Biological Activity per se in Dark-Grown Dwarf (le5839) Seedlings of Pisum sativum

摘要

Dwarf (le⁵⁸³⁹) seedlings of Pisum sativum respond to gibberellin A20 (GA20) in the dark, although the same dosage of GA20 applied to light-grown le⁵⁸³⁹ seedlings elicits no growth response. The acylcyclohexanedione growth retardant, LAB 198 999, which is known to inhibit gibberellin oxidation and in particular 3β-hydroxylation such as the conversion of GA20 to GA1, also inhibits the growth response of dark-grown dwarf (le⁵⁸³⁹) seedlings to GA20. Thus, the biological activity of GA20 in the dark appears to be a consequence of its conversion to GA1, even though it is known from studies with light-grown seedlings that the le mutation reduces the conversion of GA20 to GA1.