Symbiotic Microorganisms and Soybean: An Effective Strategy to Enhance Plant Hydraulic Efficiency and Survival Under Drought
摘要
This work evaluated the use of microorganisms in the attenuation of physiological and hydraulic (water transport through xylem vessels) damage caused by drought in Glycine max. Plants, either inoculated with microorganisms (Bacillus subtilis, Bacillus amyloliquefaciens, and Trichoderma asperellum) or left uninoculated as controls, were subjected to drought stress for 10 days. Following re-watering, the plants were monitored until the full recovery of physiological processes. It was observed that soybean plants have high plasticity of the xylem vulnerability to embolism (measured as P50 values), which allows the balance of growth and water transport safety under stress. In plants treated with microorganisms, other aspects of water balance were also affected. Indeed, although stomatal and cuticular transpiration were similar in all plants subjected to stress, inoculated plants were able to maintain higher water transport in the stem and leaf and, consequently, exhibited higher water content in leaves and a delay in the loss of 88% of hydraulic conductivity. By maintaining hydraulic functionality, microorganisms not only decreased cellular damage induced by drought but also ensured faster recovery when water was available again in the soil, which is crucial for short-life-cycle plants. In left uninoculated plants, the association of cellular damage and the influence of non-hydraulic factors on stomatal functioning delayed the recovery of photosynthesis. The study underscores the synergistic benefits of combined microbial inoculation, enhancing drought resilience through improved hydraulic conductivity, increased leaf venation density, and root biomass. These findings provide valuable insights into sustainable agricultural practices, demonstrating that microbial inoculation can significantly mitigate drought impacts, ensuring faster recovery and maintaining productivity in soybean crops.