The Stimulation by Gibberellic Acid of Cell Wall Synthesis in the Dwarf Pea Plant

Gibberellic acid (GA) brought about an increase in the rateof dry-weight incorporation into expanding internodea of intactdwarf pea seedlings. The amount of water present in expandinginternodes was closely correlated with internode dry weight,and the slope of the relation was unaffected by GA treatment.It is proposed that the effect of GA upon internode expansionis mediated through the change in dry weight. Part of the increasein dry weight brought about by GA was attributable to an increasein the weight of cell wall material. The amount of water presentin expanding internodes was found to be correlated with theamount of wall material present. It is possible that the increasedrate of wall synthesis which follows GA treatment allows anincrease in the rate of cell expansion.