Acid rain (AR) is an increasingly serious environmental problem that frequently occurs in Southern China with sulfuric acid rain (SAR) as the main type. SAR can negatively affect the growth and physiological properties of trees, but mycorrhizal associations may mitigate such detrimental effects. However, the mechanisms by which arbuscular mycorrhizal fungi control SAR-induced impacts on Torreya grandis plants remain unclear. A pot experiment was conducted on T. grandis seedlings, an economically important tree species in Southern China, in which inoculated and non-inoculated T. grandis seedlings were subjected to three simulated SAR regimes (pH of 5.6, 4.0, and 2.5, respectively) to examine the effects on the growth, osmotic regulation, and nutrient absorption of these seedlings. The results show that, although SAR had no effect on the accumulation of biomass, it significantly decreased the concentrations of proline and soluble protein, shoot Zn2+, P, K+, and Ca2+ concentrations, and the Fe2+ and Mn2+ concentrations of shoots and roots. Mycorrhizal inoculation, especially with Rhizophagus irregularis, significantly increased total biomass, proline concentration, and the Zn2+, P, and K+ concentrations in the shoots of T. grandis under lower pH conditions. Moreover, our findings suggest that the combination of root colonization, acid tolerance, and the concentrations of shoot-P, shoot-Zn2+, and root-Fe2+ of T. grandis jointly conferred mycorrhizal benefits on the plants under SAR conditions. Given the enhancement of the nutritional quality of T. grandis owing to mycorrhizal associations, inoculation with R. irregularis may be preferable for the culturing and management of these plants under acidic conditions.

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Arbuscular mycorrhizal fungi (AMF) are often considered bioameliorators. AMF can promote plant growth under various stressful conditions; however, differences between male and female clones in mycorrhizal strategies that protect plants from the detrimental effects of salinity are not well studied. In this study, we aimed to examine the interactive effects of salinity and AMF on the growth, photosynthetic traits, nutrient uptake, and biochemical responses of Morus alba males and females. In a factorial setup, male and female M. alba clones were subjected to three salinity regimes (0, 50, and 200 mM NaCl) and planted in soil with or without Funneliformis mosseae inoculation. The results showed that NaCl alone conferred negative effects on the growth, salinity tolerance, photosynthetic performance, and shoot and root ionic ratios (K+/Na+, Ca2+/Na+, and Mg2+/Na+) in both sexes; in contrast, mycorrhizal inoculation mitigated the detrimental effects of salinity. Furthermore, the mycorrhizal effects were closely correlated with Mn2+, proline, and N concentrations. Females benefited more from AMF inoculation as shown by the enhancements in their biomass accumulation, and N, proline, K+, Mg2+, Fe2+, Zn2+, and Mn2+ concentrations than males with mycorrhizal inoculation under saline conditions. In comparison, male plants inoculated with AMF showed improvements in biomass allocated to the roots, P, and peroxidase concentrations under saline conditions. These sex-specific differences suggest that male and female mulberry clones adopted different mycorrhizal strategies when growing under saline conditions. Overall, our results provide insight into the sex-specific difference in the performance of AMF-associated mulberry clones, suggesting that female mulberry could be more suitable for vegetation remediation than the male one, due to its higher salinity tolerance.