Abstract
THE REPLACEMENT of chemical fertilizers by rhizobacteria (PGPR) for promoting maize plant growth and productivity was in the aim of the present study. In the current study, rhizobacterial strains were isolated from the rhizosphere of Trifolium alexandrina L. and Trifolium aestevum L. plants cultivated in Nubaria, Egypt., The isolated bacteria were purified and were then identified as Bacillus subtilis, P. pseudoalcaligenes, Kocuria marina, Bacillus cereus, Kocuria rhizophila, Bacilus subtilis subsp. qingdao, Pseudomonas putida, Bacillus licheniformis, Bacillus thuringiensis, Bacillus subtilis subsp. Spizizenii. The rhizobacterial strains were then applied at 6 different combinations, for evaluation of their effects on maize seedling growth. All bacterial combinations increased the total fresh weight of the plant shoot while only combinations 1, 3, 4 and 6 increased that of root. The results obtained showed that combination 6 was the best followed by combination 4 in inducing the extension growth and weight of shoots and roots of maize seedlings (14-day- old). Both combinations included two Bacillus spp. two Pseudomonus spp. and one Kocuria sp. The photosynthetic pigment efficiency showed remarkable increases by four bacterial combinations (1, 3, 4 and 6). The protein to carbohydrate ratio showed appreciable increases by those bacterial combinations. Proline content in maize shoot increased by 5 bacterial combinations (1, 3, 4, 5, and 6) with a maximum increase by combination 6. The shoot antioxidant capacity increased by treatment 3 but that of root was induced by all the bacterial combinations. Protein profiles indicated marked a variation in the number of the newly formed bands, in response to the applied bacterial combinations.