Calcium (Ca) is one of essential elements for plant growth and development, and also plays a role in regulating plant cell physiology and cellular response to the environment. Here, we studied whether calcium played a role in enhancing tolerance of plants to acid rain stress by hydroponics and simulating acid rain stress. Our results show that acid rain (pH 4.5/pH 3.0) caused decreases in dry weight biomass, chlorophyll content and uptake of nutrients elements (NO₃^-, P, K, Mg, Zn and Mo) and an increase in membrane permeability of root. However, all parameters in soybean treated with exogenous calcium (5 mM) and acid rain at pH 4.5 were closed to the control levels. In addition, exogenous calcium (5 mM) alleviated the inhibition induced by pH 3.0 acid rain on the activity of plasma membranes H⁺-ATPase and the expression of GmPHA1 at transcriptional level, being benefiting to maintaining uptake of nutrients (NO₃^-, P, K, Mg, and Zn), and then lower the decrease in dry weight biomass and chlorophyll content. After a 5-day recovery (without acid rain stress), all parameters in soybean treated with acid rain at pH 3.0 and exogenous calcium were still worse than those of the control, but obviously better than those treated with acid rain at pH 3.0. Higher activity of plasma membrane H⁺-ATPase in soybean treated with acid rain at pH 3.0 and exogenous calcium was good to uptake of nutrients and promoted the recovery of soybean growth, compared with soybean treated with acid rain at pH 3.0. In conclusion, exogenous calcium could alleviate the inhibition caused by acid rain on soybean growth by increasing the activity of plasma membrane H⁺-ATPase for providing driving force to nutrient absorption, and its regulating effect was limited by intensity of acid rain. Furthermore, the application of exogenous calcium can be one of ways to alleviate the damage caused by acid rain to plants.

钙（Ca）是植物生长发育必需的元素之一，在调节植物细胞生理和细胞对环境的反应中发挥着作用。在这里，我们通过水培和模拟酸雨胁迫来研究钙是否在增强植物对酸雨胁迫的耐受性方面发挥作用。我们的结果表明，酸雨（pH 4.5/pH 3.0）导致干重生物量、叶绿素含量和营养元素（NO ₃ ^- 、P、K、Mg、Zn 和 Mo）的吸收减少，以及根系膜渗透性增加。然而，经外源钙 (5 mM) 和 pH 4.5 酸雨处理的大豆的所有参数均接近对照水平。此外，外源钙（5 mM）减轻了pH 3.0酸雨对质膜H ⁺ -ATP酶活性和转录水平GmPHA1表达的抑制，有利于维持营养物质（NO ₃ ^- 、P）的吸收。 、K、Mg 和 Zn），然后降低干重生物量和叶绿素含量的减少。恢复5 d后（无酸雨胁迫），pH 3.0酸雨和外源钙处理的大豆各项指标仍差于对照，但明显优于pH 3.0酸雨处理。与pH 3.0酸雨处理的大豆相比，pH 3.0酸雨和外源钙处理的大豆质膜H ⁺ -ATP酶活性较高，有利于养分的吸收，促进大豆生长的恢复。 综上所述，外源钙可以通过提高质膜H ⁺ -ATP酶活性为养分吸收提供驱动力来缓解酸雨对大豆生长的抑制，但其调节作用受到酸雨强度的限制。此外，施用外源钙也是减轻酸雨对植物损害的途径之一。