Effect of nitric oxide on x-ray sensitivity of Crotalaria intermedia seeds

Abstract

Nitric oxide and oxygen effect were studied in dry seeds of Crotalaria itermedia equilibrated to relative humidities of 5,32 and 80%. The frequency of mutated sectors appearing in the first leaf was used as the measure of X-ray sensitivity. The results indicate that nitric oxide enhances the effect of X-rays at all moisture levels studied, and that the nitric oxide effect increases with increase in seed moisture content. Pretreatment with nitric oxide eight days before irradiation was also found to enhance the sensitivity under anoxia. The observed oxygen effect shows an inverse relationship with seed moisture content. It is suggested that the moisture effect observed under aerobic conditions may be complex with components due to moisture, oxygen and the interaction of the two. Possibly, oxygen dissolved in the seed moisture also modifies the effect and for isolating the truly oxygen-independent effect it would be important to eliminate these last traces of dissolved oxygen.