Fungal biofertilizers have shown great potential as an ecofriendly source of plant nutrients and are important component of integrated nutrient management and plant nutrition system. In the present study, conidial suspension (CS) or culture filtrate (CF) of the isolated fungi from rhizosphere; Penicillium chrysogenum (AUMC 14100), and Aspergillus niger (AUMC f14260) were applied to soils fertilized either with rock phosphate or superphosphate. The two potent fungal strains were applied either separately or in mixed culture, alone or with chemical fertilizers. The results showed a noticeable reduction in soil pH and a significant increase in Mg+2, and Ca+2 contents and the organic matter compared to the non-inoculated soils. Moreover, the application of these fungal inducers enhanced the concentration of soluble phosphates compared to control plants or chemically fertilized soils. Phosphate fertilizer boosted both the fresh and dry weights of the shoots, with superphosphate surpassing rock phosphate. The chlorophyll and carotenoids contents of inoculated pepper plants with or without chemical fertilizers upregulated compared to the corresponding non-treated plants. The CF of the two fungi gave the considerable promotion capacity of protein, amino acids, and carbohydrate biosynthesis, compared to CS with the highest values achieved in the consortium of A. niger and P. chrysogenum. Various treatments of biofertilizers and/or chemical fertilizers compared to non-fertilized control plants showed a decrease trend for hydrogen peroxide, superoxide anion and lipid peroxidation. Interestingly, the improvement of enzymatic antioxidants and phosphate related traits were achieved by application of fungal inducers.
Key words: Aspergillus niger, Penicillium chrysogenum, P-solubilization, pepper, rock phosphate, superphosphate.
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