This experiment was carried out to study the efficiency of soil inoculation with Azotobacter chroococcum and Bacillus megaterium var. phosphaticum on some enzymes activity in presence of tomato wilting fungi. Obtained results showed that tomato inoculation with the mixture of A. chroococcum and B. megaterium var. phosphaticum gave higher values of dehydrogenase activity (DHA) as compared with individual inoculation treatments. Tomato inoculation with A. chroococcum or B. megaterium var. phosphaticum in combination with soil infestation with either F. oxysporum f.sp. lycopersici or F. solani significantly increased DHA compared to un-inoculated ones.Tomato inoculation with B. megaterium var. phosphaticum significantly increased the phosphatase activity rather than that inoculated with A. chroococcum. Dual inoculation with A. chroococcum + B. megaterium var. phosphaticum gave significant increase in phosphatase activity rather than the individual inoculation with either A. chroococcum or B. megaterium var. phosphaticum. Tomato inoculation with A. chroococcum only significantly increased N2–ase activity as compared to other investigated treatments. Also , soil infestation with either F. oxysporum f.sp. lycopersici or F. solani in combination with the mixture of two studied plant growth promoting rhizobacteria (PGPR) showed higher records of N2-ase activity than that inoculated with A. chroococcum only. Soil infestation with either F. oxysporum f.sp. lycopersici or F. solani significantly decreased the peroxidase and polyphenol oxidase content in tomato plants. Tomato inoculation with PGPR significantly increased the peroxidase and polyphenol oxidase content in tomato plants compared to the un-inoculated ones. Tomato inoculation with PGPR combined with soil infestation with pathogenic fungi significantly increased the content of peroxidase and polyphenol oxidase as compared to soil infestation with pathogenic fungi only.
Key words: dehydrogenase, phosphatase, nitrogenase, peroxidase, polyphenoloxidase, Azotobacter, Bacillus, tomato.
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