The role of gibberellin in regulation of dwarf plants development

The effect of exogenously applied gibberellic (GA₃) acid on developmental processes in dwarf pea and dwarf maize seedlings was studied. Plants responded to the phytohormone by accelerated longitudinal growth rate and apparent shortening of developmental phases. Poly(A)-mRNA population isolated from gibberellin-treated pea or maize seedlings exhibited much higher translational activity per mRNA unit in the cell-free wheat germ system when compared with control, untreated plants. Analysis of in vitro translation products made by means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS—PAGE) followed by autoradiography and densitometry revealed markedly increased overall intensity of the labelled polypeptide bands in addition to the new protein bands which started to appear in gibberellin-treated pea and maize seedlings while were still not detectable in the control plants of the same age. The banding pattern of translation products programmed by poly(A)-mRNA extracted from 2 days older untreated pea plants resembled that of the gibberellin-treated 2 days younger seedlings. It is concluded that gibberellic acid applied to dwarfs accelerates not exclusively the longitudinal growth of plants but also promotes their transition to the next developmental phases.