ACTIVATION OF DETOXIFYING ENZYMES IN TOMATO ROOTS FOLLOWING PARAQUAT TREATMENT AND NEMATODE INFECTION

G. Guida, G. Zacheo, T. Bleve-Zacheo

Abstract


Highly reactive oxygen radicals are often involved in plant stress. Plants react to the environment adversity by activating enzymes involved in oxygen detoxifications. Tomato roots were analyzed after nematode infection and paraquat treatment. It was found that paraquat increased the superoxide dismutase activity more than nematode infection and this was accompanied by an increase in peroxidase activity. Cytoplasmic and cell wall peroxidases from infected and paraquat treated seedlings were examined. Pronounced differences were noticed between the paraquat-treated and untreated tissue extracts. Gel electrophoresis showed the presence of an anionic fast migrating isoperoxidase group with a high syringaldazine-oxidase activity. It appears that paraquat induced a great increase of the two detoxifying enzymes than nematode infection. Increase of superoxide dismutase and peroxidase activity results to be an adaptive response which provides the plant with protection against biotic or abiotic stress.

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