Contents and Recovery of Gibberellins in Monoecious and Gynoecious Cucumber Plants

Abstract

Diffusates from seedlings and root exudates from 6-week-old plants of a monoecious line of cucumber, Cucumis sativus L., contained considerably higher levels of gibberellin-(GA) like substances than did those from plants of an isogenic gynoecious line. Most of the GA-like activity was found in a chromatogram region typical of GA1 and GA3; some activity, particularly in root exudates, appeared also at an RF similar to that of GA4 and GA7. When seedlings were treated with 3H-labeled GA1, more radioactivity was found in the diffusates from monoecious seedlings than from gynoecious ones. The same was true of bio10gical activity in root diffusates from older plants which had been treated with gibberellin A4+7. In conjunction with evidence present in literature, these results support the idea that endogenous GAs play a part in the regulation of sex expression in cucumber, relatively high levels favoring the formation of staminate f10wers.