GAMMA-IRRADIATION DAMAGE TO LEAF VACUOLE MEMBRANES OF CHELIDONIUM-MAJUS

The effect of gamma-irradiation on membranes of leaf vacuoles from Che lidonium majus was investigated. Exposure of the isolated membranes to 200 Gy gamma-irradiation decreased the amount of radiosensitive unsat urated fatty acids; these reductions were alleviated in vacuolar membr anes irradiated in vivo. A similar alleviation was noted for SDS polyp eptides. As a result of gamma-irradiation on leaves, the amounts of lo w molecular weight substances detectable by HPLC and capillary electro phoresis were augmented in the vacuole, probably due to an alteration of permeability properties. These observations support the postulate t hat vacuolar membranes were damaged by the ionizing radiation and that certain mechanism(s) in normal cells protected the tonoplast from the radiation.