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 sativum1

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.