Inhibition by fusicoccin of germination of pea seeds.

Fusicoccin inhibits the germination of pea (Pisum sativum L. cv Progress 9) seeds by decreasing the growth of the embryonal axis and by stimulating the fresh weight increase of the cotyledons. The growth of isolated embryonal axes in the presence of sucrose and KCl is stimulated by fusicoccin. The effect of fusicoccin on the seeds is not counteracted by sucrose and KCl. Fusicoccin promotes preferentially in the cotyledons a hyperpolarization of the transmembrane electric potential and an increase in the uptake capacity, suggesting the reinforcement of the sink strength of the cotyledons in comparison with the one of the embryonal axis and therefore the inhibition of translocation from the cotyledons of some substance necessary for the growth of the embryonal axis.