Effects of High Temperatures on Dry Seeds

Abstract

Previous reports demonstrated that heating of dry bacterial cells and spores to high temperatures in vacuum induced a high frequency of mutations. The treatment was designed to inflict genetic damage to DNA without excessive lethality to the cell (protection of protein by drying in vacuum). To study these effects in higher plants, dormant seeds of Raphanus sativus, Brassica napus, Nigella damascena, and Hordeum vulgare were dried and heated (16 minutes) in vacuum. Survival was obtained at a temperature of 122-138[degree]C which was up to 35t higher than without vacuum. Such treatment produced delay and inhibition of germination for more than 4 months (N. damascena); both effects were relieved by gibberellic acid and, to a lesser degree, by kinetin but not by thiourea. Pronounced morphological changes in the resulting plants were also produced. Some of these changes may resemble the effects of ionizing radiation.