Radiation-induced abscopal stimulation of primary leaves in Phaseolus vulgaris

Eight-day old seedlings of kidney bean (Phaseolus vulgaris) var. Vaghya were irradiated with X-rays at a dose rate of 100 R/min. Specific part-irradiation on the intact seedling was carried out subsequently giving 5 KR 60Co at 100 R/min dose rate. Results show that: (1) doses over 250 R stimulate dry weight accumulation in primary leaves, (2) the highest effect is seen in 2000 R and 5000 R which also significantly improve chlorophyll level expressed on per disc alone. The effect is comparable to detopping, (3) irradiation of apex is more stimulatory than that of whole plant, (4) irradiation of only primary leaves is slightly inhibitive in the early period but more inhibition is shown by 20th day. (M.G.B.)