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

Abstract

The amount of gibberellin-like substances in the seed of Pharbitis nil increased in parallel with the growth of the seed, and attained 20 days after anthesis to a maximum of 0.115 μg gibberellin A3 eqivalent per seed, when the seed reached its maximum fresh weight or four-fifths of its final dry weight. At this maximum level, 0.03 μg and 0.1 μg gibberellin A3 equivalents were localized in the embryo and in the “endosperm”, respectively. Three gibberellin-like substances (Factors I, II and III) were separated upon paper chromatography. In view of the changes in amount of the factors with respect to the seed maturation, these factors, especially Factor II, in the “endosperm” and embryo were assumed to participate in the initial or the main part of growth of the embryo. Dwarf rice seedling and maize dwarfs 1, 3 and 5 responded to the three factors nearly in the same way. Pharbitis dwarf, however, responded only to Factor I, but not to Factors II and III.