GIBBERELLINS IN ENDOSPERM AND EMBRYOS OF MARAH MACROCARPUS

Endogenous gibberellins (GAs) have been identified by GC-mass spectrom etry in homogenates of the endosperm and embryos of Marah macrocarpus seeds, before and after fractionation of proteins by ammonium sulphate precipitation, followed by Sephadex G-25 filtration. The unfractionat ed endosperm homogenate contained GA(3), GA(4), GA(4)-diacid, GA(7), G A(7)-isolactone, GA(7)-diacid, GA(25), GA(37), GA(43), GA(46), GA(62) and the putative 2 beta, 12 alpha-dihydroxyGA(62), 12 alpha-hydroxyGA( 43) and 2 beta-hydroxyGA(84); the amounts of these GAs were 2-100 mu g g(-1), except for GA(3) and GA(62), which were present in much lower amounts. The fractionated endosperm homogenate still contained GA(4), GA(7), GA(7)-isolactone, GA(25), 2 beta,12 alpha-dihydroxyGA(25), and GA(46), but in reduced amounts (less than or equal to 1 mu g g(-1) end osperm). The unfractionated embryo homogenate contained comparable amo unts of the same GAs, as in the unfractionated endosperm homogenate, e xcept for the absence of GA(7)-diacid, GA(62), the putative 2 beta,12 alpha-(OH)(2)GA(25) and the putative 12 alpha-OHGA(43); GA(1) and GA(1 3) were also present. In contrast to the endosperm, no GAs were detect ed in the fractionated embryo homogenate.