FREE AMINO ACIDS AND OXIDATIVE ENZYMES IN INFESTED ROOTS OF TOMATO GENOTYPES RESISTANT AND SUSCEPTIBLE TO MELOIDOGYNE INCOGNITA

Horeya M. Hassan, A. M. Khalf-Allah, I. K. A. Ibrahim, H. M. Badr

Abstract


The effects of Meloidogyne incognita on the free amino acid contents of resistant and susceptible roots of different tomato genotypes were studied. Fourteen free amino acids were commonly found in the roots of all tomato genotypes. Proline, cystine and tyrosine were not detected in some of the tested tomato populations. The concentrations of the amino acids asparagine, therionin + serine, alanine, valine and leucine appeared to have low value in the resistant genotypes in most instances. On the other hand, the amino acids glutamine, histidine, giycine and arginine occurred in higher concentrations in the resistant genotypes in most instances. The activity rates of the oxidarive enzymes peroxidase, polyphenol oxidase, ascorbic acid oxidase and catalase showed significantly higher values in the resistant tornado genotypes of parental cultivars than in susceptible ones.

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