Response of Antioxidant Substances and Enzymes Activities as a Defense Mechanism Against Root-Knot Nematode Infection

The organic amendments, composts (1, 2, 3), neem and poultry as well as inorganic fertilizers (NPK compound and commercial, Athree®) and the nematicide nemacur 10 G applied singly were effective in reducing M. incognita number of galls, nematode reproductionand fecundity. The effectiveness seemed to be material origin dependent. Neem, compost 1, 3 (5 g/pot) gave the best results. Yet, achievedresults were less than those of nemacur 10% G. The antioxidant substances content and enzymes activities due to nematode infectionand application of organic and inorganic fertilizers pointed to significant increase of lipid peroxidation and hydrogen peroxide as aresult of nematode infection and nemacur treatment. While all organic and inorganic fertilizers reduced such materials with significantdifferences among treatments. Likewise, nematode infection resulted in slight but significant increase in glutathione and ascorbic acidin tomato shoots and roots. All treatments increased antioxidant substances comparing to healthy and infected plants. Glutathione-Stransferaseactivity highly increased in infected roots but the lowest activities were achieved by organic fertilizers. Nematode infectionand nemacur treatment increased slightly phenylalaine ammonia lyase activity but enormous increase was observed in shoots and rootsof treated plants with organic fertilizers followed by NPK treatments.

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