Elevated CO₂ levels may alleviate toxicities induced by environmental stresses in plants, such as heavy metals. To assess this possibility, seedlings of Lolium perenne L. were exposed to different Cd stress and CO₂ levels during hydroponic culture. The kinetics of growth, Cd accumulation, and thiol formation were investigated. Elevated CO₂ levels increased the growth rate from 30 to 75%, and decreased the Cd accumulation rate from 36 to 42%, leading to a decrease of Cd content in root and shoot. However, an increase in Cd transport from root to shoot was observed at elevated CO₂ under Cd stress. The production of phytochelatins (PCs) occurred earlier at elevated CO₂ level than at ambient CO₂ level after exposure to Cd stress. The mean SH/Cd ratio was relatively higher at elevated CO₂ level, but elevated CO₂ level significantly decreased thiol contents. The reduction of Cd contents, earlier production of PCs, and relatively higher SH/Cd ratio at the elevated CO₂ level alleviated Cd toxicity in root and shoot to some extent, causing significant yield increase of L. perenne after exposure to Cd stress. This study could provide an important data support and theoretical basis in understanding the effects of elevated CO₂ on plant growth, heavy metal accumulation, and thiol formation.

升高的CO ₂水平可减轻植物等重金属等环境胁迫引起的毒性。为了评估这种可能性，在水培培养过程中，黑麦草的幼苗暴露于不同的Cd胁迫和CO ₂水平。研究了生长，Cd积累和硫醇形成的动力学。升高的CO ₂水平使生长速率从30％增至75％，而Cd累积速率从36％降低至42％，导致根和茎中Cd含量降低。但是，在Cd胁迫下，CO ₂浓度升高时，从根到芽的Cd转运增加。植物螯合素（PCs）的产生是在CO ₂升高时发生的较早暴露于Cd胁迫后的水平要高于环境CO _2的水平。在升高的CO ₂水平下，平均SH / Cd比相对较高，但升高的CO ₂水平则显着降低了硫醇含量。Cd含量的降低，PCs的早期生产以及在较高的CO ₂水平下相对较高的SH / Cd比在一定程度上减轻了Cd在根和芽中的毒性，在暴露于Cd胁迫后，紫苏的产量显着增加。该研究可以为理解CO ₂浓度升高对植物生长，重金属积累和硫醇形成的影响提供重要的数据支持和理论基础。