Hormonal regulation of sex expression in <i>Momordica charantia</i>

Abstract

Sex expression in a monoecious cucurbit, Momordica charantia L. (long–fruited variety ‘Karela’) can be regulated by application of gibberellin A 3 (GA 3 ), indole‐3‐acetic acid (IAA) and 3‐hydroxymethyl oxindole (HMO), an oxidation product of IAA, all of which promote female flowering. Both IAA and HMO accelerated ethylene evolution in the seedlings of this plant. While a low concentration of Ethrel promotes flowering, the effect was reversed with increased concentrations. Surprisingly, GA 3 was the most effective growth regulator in increasing, femaleness. In untreated plants, levels of endogenous GA‐like substance increased progressively up to the age of 60 days, at which the ratio of male to female flowers was minimum.