Is seed coat structure at fault for altered permeability and imbibition injury in artificially aged soybean seeds?

Abstract

AbstractAgeing induces many deteriorative changes to seeds during storage like genetic damage, protein degradation, enzyme inactivation and loss of membrane integrity. In this study, we subject to investigate the alterations in seed coat structure and its permeability properties due to accelerated ageing affecting the subsequent imbibition of soybean [Glycine max (L.) Merr.] seeds. Two contrasting seed coat colour genotypes, JS 335 (white) and Bhatt (black) were selected and artificially aged for 48 and 72 h. The results of seed ageing on permeability, imbibition and germination proved that permeability and imbibition increased but germination decreased in white genotype due to imbibitional injury, whereas germination increased in black genotype due to breaking of hard seed coat imposed dormancy. The hard seeds in the black genotype with a different seed coat structure compared to the white genotype prevented imbibition injury in aged seeds by regulating permeability. Microscopic studies of seed coat structure in aged seeds revealed a thick cuticle with small hilar fissure and compact, dense hourglass cells in black genotype compared to a thin cuticle with large hilar fissure and loosely packed and distorted hourglass cells in white genotype. Thus the altered permeability and imbibition injury in artificially aged seeds is shown to occur mainly as a result of altered and damaged seed coat structure.