In vitro effect of thiabendazole on enzymes of plant tissues.

Thiabendazole, a systemic fungicide, at 0.5 mM conc. inhibited mitochondrial succinate dehydrogenase activity by 30-60% in germinating seeds of Cicer arietinum and Phaseolus radiatus [Vigna radiata]. Mitochondrial succinoxidase and phosphorylating capacity were inhibited only in P. radiatus. It inhibited the mitochondrial NADH-cytochrome c reductase of C. arietinum by 50%, but had no effect on mitochondrial succinate-cytochrome c reductase, malate dehydrogenase, ATPase, L-asparatate:2-oxoglutarate aminotransferase and cytoplasmic phosphorylase, peroxidase, catalase and polyphenol oxidase activities in germinated seeds. Thiabendazole reduced mitochondrial succinate dehydrogenase activity in fruits of various spp. including P. vulgaris and tubers of potato and sweet potato.