Environmental Conditions That Modify Plant Response to Neutron Irradiation.

Abstract

Various environmental factors that influence response to irradiation in both "wet" and "dry" plant systems are reviewed. The oxygen-jffect, expressed quantitatively as the oxygen enhancement ratio (OER) is lower for neutrons (1.3-1.9) than for sparsely ionizing radiations. X and v rays give OER's of 2.4 to 3.4 in wet systems and 10-15 in very dry seeds (2-3% water content)« Water appears to regulate the degree to which radiation induced oxygen-sensitive sites or radicals interact with oxygen to produce radiobiological damage. The effact is less with neutrons than with x irradiation. Control over mutagenie or other specific radiobiological responses may lie, not so much in specific reactions with DNA, but more with cellular processes that precede or follow treatment, so that preferential recovery may take place. Examples are given of some environmental perturbations that show promise for altering response to neutron irradiation.