Correlation of Nuclear Volume and DNA Content with Higher Plant Tolerance to Chronic Radiation

Abstract

The causes of extreme differences in radiosensitivities of different plant (or animal) species have long puzzled radiobiologists. Our investigations show that, for diploid species, the larger the nuclear volume, the more radiosensitive the organism. Correspondingly, species with large nuclei have more deoxyribonucleic acid (DNA) per nucleus than those possessing small nuclei. Our data now make it possible to predict fairly accurately the tolerance of plant species to ionizing radiation on the basis of average nuclear volume and DNA content. The same correlations are expected to hold for some microorganisms and for animals and may explain differences in sensitivities of different cell types in many living organisms.

Nuclear DNA variation in the genus Allium L. (Liliaceae)

“…3), indicating that the DNA concentration per unit volume is constant in all Allium species studied. This relationship was first proposed by Sparrow and Miksche (1961) and Van't Hof and Sparrow (1963) and has been confirmed in a range of angiosperms e.g., Phaseolus (Ayonadhu, 1974), Lathyrus, Vicia (Rees, Cameron, Hazarika and Jones 1966), Anthemideae (Nagi and Ehrendorfer, 1974) and Gramineae (Sparrow and Nauman, 1974). In Eu-Sorghums, however, Paroda and Rees (1971) reported a significantly different correlation in this respect between the wild and cultivated species, indicating that there is a sharp distinction between these two species groups in terms of DNA density.…”

Do Plants Have a One-Way Ticket to Genomic Obesity?

“…resistance to radiation, and optimum environment for growth (Sparrow and Miksche, 1961 ;Van't Hof and Sparrow, 1963;Bennett, 1972Bennett, , 1976; Rayburn et al, 1985). If Although the mechanisms of retrotransposon amplification are clear and well characterized, a mechanism for the remova1 of substantial quantities of interspersed repetitive DNA has not been identified in plants (but see Petrov et al, 1996, for an example from Drosophila).…”

An upper limit of the ratio of DNA volume to nuclear volume exists in plants

“…Comparisons of the nuclear sizes of various higher plants were reported in relation to their radiosensitivity Edited by Minoru Murata (Sparrow and Miksche, 1961;Baetcke et al, 1961). However, the relationship between nuclear DNA contents and nucleus, particularly in terms of the nuclear volume, remains unclear in plant.…”