Changes Induced in Acidic and Neutral Fractions by GA,1

Summiary. Immature (8-mmii11), miie(liumiii mature (1l-mm), andI muature green (16an1d 17-mm1ni) )ean seeds (Phlaseolis zvitlgaris L. cv. Ken,tucl-y \Wonder andl Bountiful) were incubated in gil,bberellin A1 soluitionis for 24 lhours at 200. Extracts from the seeds were separated ilnto nionacidic, acidic ethyl acetate, and acidic butalnol fractionis. These were chromatographed. The eluates of the chromatograiims were tested on Progress No. 9 dwarf peas grown under red light. The level of neutral gibberellin-like substances reniained unchanged in imiimature seed, but they increased markedly in miature green seeds. Coincident with increased levels of the neutral suibstances, there were significant decreases in acidic ethyl acetate-soluble gibberellin-like sub-stances, includinig applfied GA1. and in 1 acidic butanol-soluble gibberellin-like substance. Seed incubation in GA1 broughit about increased activity of substance B-lI in immllature andcl mediunm miiature seeds. The level of butanol-soluble gibberellin-like substance B-I in seeds of anly size wvas noit affected by incubation in GA1. Considering the n:arkedI inicreases in activity induced in the neutral fraction and the decreases in activity of certain eluates from the chromatograln's of the acidlic fracitions, it was concluded that the neutral fraction may serve as a reserve form of gibberellinis in the dry seed. The aci(lic ethyl acetate substances and substance B-II may be required for normal development of the bean seed.