STIMULATION OF GROWTH OF SOY BEAN SEEDS BY SOFT X-RAYS

Abstract

Dry soy beans were irradiated with soft x-rays produced by a Cu target tube operated at several different voltages and 10 ma., with the seeds 3.3 cm. from the focal spot. The most intense part of the spectrum was the K[alpha] line of copper (1.54 A.). Irradiation times ranged from 5 to 25 sec. in steps of 5 sec. The irradiated seeds and unirradiated controls were planted in the open field. Over 12,000 Manchu soy bean plants grown from seed irradiated at 20 peak KV. showed 2.3% greater average wet weight (of the part above ground) for those grown from seed irradiated 10 sec. than for the control. Each of three lots of Wilson Black soy bean plants grown from seeds irradiated at 25, 30, and 35 peak KV., respectively, showed a maximum stimulation corresponding to 5 sec. of irradiation, the average of the 3 lots being 5.9% greater than the control. A slight real stimulation is indicated.