A Physical Explanation for Solute Leakage from Dry Pea Embryos During Imbibition

Abstract

The pattern of solute leakage from imbibing dead pea (Pisum sativum L.) embryos was the same as that from living embryos, with an initially high leakage declining to a low constant rate of leakage in the first 3 min of imbibition. The same pattern of leakage occurred during each imbibition phase of repeated imbibe/dry cycles of dead embryos. Living and dead seeds also showed this pattern of leakage. These observations are used to argue that leakage during imbibition of embryos and seeds is a physical diffusion phenomenon. Vital staining of living embryos after imbibition revealed positive staining for dehydrogenase enzymes in the cells on the outer surface of the cotyledons only when 0.5 mM sodium succinate solution was present during imbibition and/or staining. This is discussed in relation to the effect of rapid water uptake on these cells.