GIBBERELLIN-LIKE SUBSTANCES OCCURRING IN THE SEED OF PHARBITIS NIL CHOIS. AND THEIR CHANGE IN CONTENTS DURING THE SEED DEVELOPMENT

The amount of gibberellin-like substances in the seed of Pharbitisnil increased in parallel with the growth of the seed, and attained20 days after anthesis to a maximum of 0.115 µg gibberellinA₃ eqivalent per seed, when the seed reached its maximum freshweight or four-fifths of its final dry weight. At this maximumlevel, 0.03 µg and 0.1 µg gibberellin A₃ equivalentswere localized in the embryo and in the "endosperm", respectively.Three gibberellin-like substances (Factors I, II and III) wereseparated upon paper chromatography. In view of the changesin amount of the factors with respect to the seed maturation,these factors, especially Factor II, in the "endosperm" andembryo were assumed to participate in the initial or the mainpart of growth of the embryo. Dwarf rice seedling and maizedwarfs 1, 3 and 5 responded to the three factors nearly in thesame way. Pharbitis dwarf, however, responded only to FactorI, but not to Factors II and III. (Received February 21, 1963; )