Proton secretion, potassium uptake and recovery of viability in aged wheat seeds.

Fusicoccin (FC), K+ and Na+ restore the viability of aged wheat seeds and isolated wheat embryos. We studied the effect of FC and K+ on the evolution of the proton extrusion activity and net K+ uptake during the early phases of germination of wheat embryos isolated from unaged and aged seeds. In aged embryos the positive effects of FC and K+ on germination were correlated with a marked increase in both proton extrusion and K+ net uptake. These findings suggest that: (a) in wheat seeds, germination is also correlated to the activation of a mechanism linked to H+/K+ exchange; (b) the damage of this mechanism is, under our conditions, responsible for the loss of viability.