Effects of Ionizing Radiations on Seeds of Barley

Abstract

The water content and/or physiological state of seeds of barley were modified by a variety of treatments prior to subjecting them to X-rays, thermal neutrons and fast neutrons. After irradiation the seeds were germinated and grown for 7 days in petri dishes at which time seedling height measurements were taken. The following observations were made: The sensitivity of seeds to X-rays is little affected and possibly decreased by soaking them in water for 1 1/2 hours at 3[degree]C prior to irradiation. However, soaking beyond this time, up to 24 hours, strikingly increases their X-ray sensitivity. Seeds soaked at this temperature for all time intervals used were less sensitive to thermal neutrons than were unsoaked seeds. However, their sensitivity to fast neutrons appeared to be proportional to their water content. When seeds are permitted to take up water by storing them at different relative humidities, there is an inverse relationship between their water content between about 7 percent and about 20 percent, and their sensitivity to X-rays. Such treatment has little influence on the sensitivity of the seeds to either thermal or fast neutrons. Seedlings from seeds soaked for various periods of time at 3[degree]C and then dried back to their original wieght were little affected by thermal and fast neutrons. However, for the longer periods of soaking there was a distinct increase in their sensitivity to X-rays.