Effects of plant growth-promoting rhizobacterica on Achnatherum inebrians seed germination during salt stress

Three different plant growth promoting rhizobacterica (PGPR) strains Pseudomonas aeruginosa、Bacillus licheniformis, and Enterobacter sp. isolated from the rhizosphere soil of Achnatherum inebrians were inoculated under different salt concentrations (0, 50, 100, 150 mmol·L⁻¹), and the seed germination and seedling growth of Epichloë endophyte-infected A. inebrians were studied. The results showed that different PGPR could significantly (P < 0.05) promote the germination percentage, germination potential, germination index, radicle length, and plumule length of A. inebrians. With increasing of salt concentration, the germination percentage, germination potential, germination index, radicle length, and plumule length of A. inebrians seeds first increased and then decreased. The germination percentage, germination potential, germination index, radicle length, and plumule length of A. inebrians were the highest at a salt concentration of 100 mmol·L⁻¹, and they were the lowest at a salt concentration of 150 mmol·L⁻¹. Inoculation with the PGPR Pseudomonas aeruginosa and Bacillus licheniformis significantly (P < 0.05) improved the germination percentage and germination potential of A. inebrians seeds at a concentration of 100 mmol·L⁻¹. Inoculation with Enterbacter sp. significantly (P < 0.05) increased the germination percentage of A. inebrians seeds under all salt treatments. Therefore, PGPR can improve the resistance of A. inebrians to salt stress, and different PGPR have different levels of resistance to salt stress.