The Effects of X-rays on the Embryonal Growth and Development ofHordeum vulgareL.

Abstract

The effects of softer X-rays as an external agent on the developing embryos were manifested by a number of abnormalities such as enlargement and vacuolation of cells, disturbances in cell walls, disintegration of cells leading to the formation of cavities, disturbances in distribution of meristematic tissues, a number of proliferations in different parts of the embryo, and retarded growth of the embryo during the early post-radiation period. In addition to these, deeply stained globular cytoplasmic bodies were observed in radiated embryonic cells. Very similar kinds of abnormalities were produced by softer X-rays starting from 400 r. and including 800 r. The frequency of occurrence and degree of proliferations in embryos irradiated with 800 r., however, were relatively higher than those produced by 400 r. and 500 r. Treatments with 300 r. units of irradiation induced only the appearance of deeply stained globular bodies within cytoplasm and no effects were visible with dosages below 300 r. Comparative measurements of cell- lengths of the treated and control embryos at undifferentiated as well as at differentiated stages showed an increase in cell-lengths within radiated embryos. Radiated embryos showed defective pattern of germination. Harder X-rays were found to be less effective in inducing embryonic abnormalities than softer rays when equal calculated dosages of the two were applied to the flowering spikes of Hordeum vulgare L.