Fusicoccin inhibits seed germination: a competition at transport level between embryo and cotyledons.

Fusicoccin inhibits the germination of pea (Pisum sativum L.) seeds by decreasing the growth of the embryonal axis and by stimulating the fresh weight increase of the cotyledons. 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 and therefore the inhibition of translocation from the cotyledons of some substance necessary for the growth of the embryonal axis.