| Abstract:
Soil salinization is an increasingly serious issue, and bioremediation techniques have garnered significant attention due to their cost-effectiveness. Bacillus amyloliquefaciens, a plant growth-promoting rhizobacterium (PGPR), has demonstrated potential in enhancing plant stress resistance and growth. However, its effects on cotton salt tolerance remain underexplored. This study aimed to assess the alleviating effects of Bacillus amyloliquefaciens on cotton growth, yield, and quality under salt stress. A field experiment was conducted using a split-plot randomized design, involving three factors: two salinity levels (S0: 0 g·kg-1 and S1: 5 g·kg-1 NaCl), two cotton varieties (salt-tolerant variety G1: LS220 and salt-sensitive variety G2: LS231), and two bacterial treatments (B0: without bacteria, B1: with bacteria), The experiment comprised a total of eight treatments, with three replicates per treatment. Salt stress significantly inhibited the growth of the G2 variety at the seeding stage. However, after adding Bacillus amyloliquefaciens, the fresh and dry weights of G2 increased by 42.5% and 33.3%, respectively, Leaf water content increased by 20.8% and SPAD values were restored to control levels. Additioally, the Na+/K+ ratio decreased, seed cotton yield increased by 10.2%, and fiber quality parameters such as upper half mean length, reflectance, micronaire value, yellowness, and spinning consistency index, were significantly improved. Correlation analysis indicated that plant height, stem diameter, leaf area, and other growth factors were significantly positively correlated with cotton yield. Additionally, although bacterial treatment did not significantly alleviate the physiological stress in the G1 variety under salt stress, it did significantly improve yield and fiber quality. Overall, Bacillus amyloliquefaciens can enhance the yield and quality of salt-sensitive cotton under salt stress by modulating physiological traits. |
