Effects of hydrogen peroxide on the germination and early seedling growth of barley under NaCl and high temperature stresses

In this work, the effects of a hydrogen peroxide (H2O2) pretreatment on the germination and early seedling growth of barley under salt (NaCl) and temperature (20o, 25o, 30o and 35oC) conditions was studied. H 2 O 2 enormously removed the germination-delaying and inhibiting effects of temperature increases. In addition, it was rather effective on alleviation of the reductive effects of temperature increases on the parameters of growth such as the percentages of coleoptile emergence, elongations of radicle, and coleoptile and fresh weights (FWs) of the seedlings. H 2 O 2 pretreatment became very successful in the overcoming of the germination-delaying and preventing effects of the increases in both salt and temperature levels. It markedly alleviated the inhibitions of salt on seedling growth at all temperatures as well. H2O2 both removed the blockage of abscisic acid (ABA) on the germination and shortened the time required for germination at 20oC, an optimal temperature, by its influsion into the seeds with pretreatment or its presence in the medium of germination. On the other hand, H2O2 relatively alleviated ABA inhibitions on the radicle elongations and FWs while it had no effect on ABA suppression on the emergence percentage and elongation of the coleoptile.