The Effect of High Doses of Radiation on Seedling Growth

Abstract

Studies on the phenomenon of reversal in the seedling height-dose curve are reported. A comparison of the coleoptile and leaf growth in barley and wheat has lent support to the postulate that the reversal is caused by an interaction of chromosome damage and mitotic inhibition. In corn, the phenomenon persisted even after a postirradiation storage of the seeds for more than 4 years. The dose at which the reversal occurs was shown to be dependent on the moisture content of the seed at the time of irradiation. With superdry seeds, which show increased radiosensitivity as compared to air-dry seeds, the reversal occurs at a lower dose.