Reduction of the Gibberellin Content of Pharbitis Seeds by CCC and After-Effects in the Progeny

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Abstract
Japanese morning glory plants (Pharbitis nil) were treated with the growth-retarding chemical (2-chloroethyl) trimethylammonium chloride (CCC) shortly before and after opening of flowers. Fresh and dry weight of immature seeds were not affected by the CCC treatment. The level of gibberellin (GA)-like activity in Pharbitis seeds was strongly reduced by CCC. The progenies of the treated plants also had a much reduced GA content in the seedling stage. The results are interpreted to indicate that CCC blocks GA biosynthesis in higher plants as it does in the fungus Fusarium moniliforme. CCC applied via the roots accumulated in the immature seeds and was carried over to the following generation. Consequently, growth of CCC progenies was dwarfed and flower formation inhibited Both phenomena were overcome by application of GA3. Three GA-like substances present in immature Pharbitis seeds were separated by thin-layer chromatography, and indicated as fractions I, II, and [II]I. Fraction I was present only in small quantities. Both fractions II and III promoted growth of Zea mays, mutant d-5, but only fraction II was active in promoting stem elongation of dwarf peas (Pisum sativum) grown under red light.