Drought Stress Alleviation in Paeoniae Radix Rubra with Three Bacillus Strains and Associated Metabolic Changes
摘要
Although Paeoniae Radix Rubra possesses good drought tolerance, its growth and yield have been somewhat affected by recent climate changes, necessitating further study to enhance its drought resilience. Research indicates that Bacillus can enhance plant tolerance to drought stress by promoting root growth, secreting plant growth hormones, enhancing antioxidant capacity, and inducing systemic resistance; however, the specific mechanisms in P. R. Rubra remain unclear. The study investigated the effect of different combinations and application frequencies of three Bacillus species (Bacillus megaterium, Bacillus amyloliquefaciens, Bacillus subtilis) applied through root drenching on growth, photosynthesis, physiological responses, and soil properties of P. R. Rubra under drought stress. Results showed that Bacillus mixtures, particularly three strains applications, significantly boosted photosynthesis, osmolytes, and antioxidants, enhancing drought tolerance. P. R. Rubra treated with Bacillus drenching twice greater drought tolerance compared to control groups. Furthermore, the treatment improved soil health by increasing nitrogen and phosphorus content in soil and enhancing soil pH, facilitating recovery after rewatering. In summary, applying a mixture of three Bacillus strains in equal proportions at a concentration of 1.3 × 1011 CFU/L through two drench treatments promoted P. R. Rubra growth and photosynthesis while improving soil conditions, ultimately enhancing the plant’s drought resistance. This approach is significant for utilizing rhizosphere bacteria to strengthen plant resilience, promote sustainable practices, reduce chemical fertilizer use, and provide insights for cultivating P. R. Rubra in arid regions.