Abstract
The dosage of beta-rays could be calculated in terms of r units, with the equations being based on the number of ion pairs produced per disintegration.
Compared with the effect of high intensity X-rays, P32 treatment was about 1/3 or 1/4 less effective in inducing chromosome aberrations. This was observed not only in the case of pollen mitosis, but also in root tip cell division. The decrease of effectiveness might be caused by the low intensity of irradiation.
