Abstract
The amount of free radicals in cowpea leaves infected with cucumber mosaic virus (CMV) markedly increased within 8hr following inoculation. When CMV-infected leaves were treated with scavengers to the free radicals, the local lesion formation was markedly inhibited. Malonaldehyde content also increased for 8-15hr after inoculation, but it decreased gradually as lesion appeared. When infected leaves were treated with dibutylhydroxytoluene, an inhibitor against lipoxygenase, the malonaldehyde content was markedly decreased. Gas liquid chromatography of the lipids extracted from infected leaves showed a reduction of unsaturated fatty acids without change in the quantity of saturated fatty acids. These results clearly indicate that lipid peroxidation occurs in the early stage of CMV-infection. Moreover, a loss of electrolytes from infected tissue rapidly occurred about 5hr after inoculation but that from uninfected tissue did not occur during the experimental period. These findings were discussed with particular reference to the hypersensitive reaction in CMV-infected cowpea leaves.
