Effects of plant growth-promoting rhizobacteria on root development in wheat
Wheat seedlings inoculated with 24 plant growth-promoting rhizobacteria(PGPR) strains isolated from the rhizosphere of wheat, cotton, and rice were cultured in the semisolid medium or potting soil. Nine growth parameters of the root and stem were measured. In the semi-solid experiment, among 9 PGPR strains that significantly promoted the root dry weight, 7 promoted the total root length, 9 promoted the total root surface area, 5 increased the number of root tips, 8 increased the number of lateral roots and the stem height, and 7 improved the stem dry weight. In the pot experiment, in 10 PGPR strains that significantly promoted the dry weight of root, 10 promoted the total root length and total root surface area, 6 increased the number of root tips, 8 increased the number of lateral roots, 9 promoted the height of stem, and 7 enhanced the dry weight of stem. Five strains showed more than 5 significant growth-promoting parameters in both semisolid and pot experiment, among which 4 strains were Pseudomonas spp., indicating that Pseudomonas had better growth-promoting effects on wheat growth. PGPRs promoted the total length of the root,total surface area of the root,the number of root tips and lateral roots significantly.These parameters had significant correlations with the root dry weight, stem height and stem dry weight.