Relationship between Nuclear Volume and Radiosensitivity of Different Cell Types in Gemmæ of Marchantia polymorpha L.

Abstract

THE radiosensitivity of various species of plants has been investigated for many years^1,2. Much recent work has been concerned with attempts to discover if there is some common cellular feature which might serve as an index of radiosensitivity. In general, the nucleus (or its components) has been considered as the primary object determining radiosensitivity^3–7. One method of investigation has been to irradiate a number of different species and then to correlate the responses of the irradiated plants with inherent particular nuclear parameters of apical meristem cells of unirradiated control plants. In general, plants with the smaller nuclei have been found to be more resistant to radiation than those plants with the larger nuclei. Indeed, where the species being compared differed in chromosome number, Sparrow et al.⁸ have shown that the quotient of the nuclear volume divided by the chromosome number (the interphase chromosome volume) is a more accurate index of radio-sensitivity than nuclear volume alone. Thus chromosome number is important in determining radiosensitivity where variation in numbers exists.