Two pot experiments were carried out during growth seasons of 2016 and 2017 at the experimental station of faculty of agriculture, Benha University. The investigation target was to find out the effect of using plant growth promoting rhizobacteria either PGPR-group (A) containing 7×109 cell suspension of each (Azo. lipoferium D178, B. megaterium ATCC14581 and B. circulans ATCC4513) or PGPR-group (B) containing 7×109 cell suspension of each (A. chroococcum EMCCN1458, B. megaterium ATCC14581 and B. circulans ATCC4513) individually or in combination with mineral fertilization rates (25, 50, 75 and100%) NPK on the vegetative growth characteristics and chemical constituents of Moringa oleifera plant at 75 and 150 DAS. The combination of plant growth promoting rhizobacteria PGPR group (A) and inorganic fertilizers treatments gave the highest values of dehydrogenase (DHA), alkaline phosphatase (ALP) and nitrogenase (N2-ase) activities as compared with each one individually. In all treatments, enzymes activities were increased to reach the maximum values after 90 DAS. The highest values of enzymes activity recorded for treatment which inoculated with PGPR group (A) and amended with ¾ of mineral fertilizers followed by treatment which inoculated with PGPR group (B) amended with ¾ mineral fertilizers. Vegetative growth measurements, photosynthetic pigments, promoting endogenous phytohormones, total phenolics, flavonoids and ascorbic acid contents as well as the highest values of antioxidants activity were recorded for treatment that inoculated with PGPR group (A) amended with ¾ of mineral fertilizers followed by treatment that inoculated with PGPR group (B) amended with ¾ mineral fertilizers, respectively compared to mineral fertilization. Abscisic acid was reduced with different applied treatments as compared to the control, but the reduction was more obviously clear for treatment of PGPR group (B) amended with ½ mineral fertilizers. While, salicylic acid was increased with the different tested treatments compared with the control and reached its maximum values with PGPR group (B) amended with ¾ mineral fertilizers and PGPR group (A) with ¾ mineral fertilizers treatments, respectively. |
