摘要:以CO₂浓度及温度升高为主要标志的全球气候变化将对我国西北地区脆弱的生态系统产生重要影响。利用环境控制实验研究CO₂浓度倍增（eCO₂，C₁：400 μmol/mol和C₂：800 μmol/mol）和温度升高（eT，T₁：20℃/10℃和T₂：23℃/13℃）对高山灌木鬼箭锦鸡儿（Caragana jubata）生长及抗氧化系统的影响。结果表明：eCO₂和eT表现出相反的生长和生理效应，eT对幼苗生长的影响要大于eCO₂对其的影响。eT使幼苗的总生物量、净光合速率（NAR）和相对生长速率（RGR）降低；但可促进地上部分生长，叶生物量比及叶面积比增加。eCO₂可减缓或补偿由eT引起的总生物量、NAR和RGR的降低，并促进地下部分生长。对抗氧化系统来说，eT使得超氧化歧化酶（SOD）、过氧化物酶（POD）及抗坏血酸过氧化物酶（APX）活性降低，还原型谷胱甘肽（GSH）和抗坏血酸（ASA）含量降低；eCO₂只增加常温下SOD酶活性，并使GSH、ASA整体水平提高。结论：温度升高和CO₂浓度倍增没有协同促进鬼箭锦鸡儿幼苗的生长和光合能力。温度升高将对幼苗生长和抗氧化系统产生不利影响，eCO₂可促进生长并可能通过抗氧剂含量增加来缓解氧化胁迫。因此，未来气候变化，尤其是温度升高将会对高寒区植物产生较大影响，CO₂浓度增加可缓解增温的不利影响。



Abstract:Global climate changes characterized by the elevation of CO₂ concentration and temperature will have significant impacts on ecosystems in Northwest China. Warming and elevated atmospheric CO₂ concentration effects have been extensively studied separately; however, their combined impact on plants is not well understood. In this study, we conduct experiments to understand the response of Caragana jubata(Alpine shrub) to the elevated CO₂ (eCO₂) and temperature (eT) using the controlled environmental test. Two different CO₂ concentrations (C₁:400 μmol/mol, C₂:800 μmol/mol) were imposed at two different temperature regimes of 20℃/10℃ and 23℃/13℃ (day/night). The results showed that the effects of eT on the seedling were greater than that of eCO₂. They showed the opposite effects. The total biomass of C. jubata was reduced by eT, and its net assimilation rate (NAR) with relative growth rate (RGR) were decreased too. The eT obviously promoted the above-ground growth, leaf mass ratio, and leaf area ratio. On the contrary, eCO₂ slowed or compensated for the reduction in total biomass, NAR, and RGR. It promoted the growth of under-ground parts of seedling. The activities of superoxide dismutase (SOD), peroxidase (POD), and ascorbate peroxidase (APX) were decreased by eT. The antioxidant contents of GSH and ASA were decreased too. eCO₂ increased the SOD activities grown under ambient temperature. It also promoted the overall levels of GSH and ASA. The adverse effects of eT on the antioxidant system of plants were partially mitigated due to eCO₂. In general, the increased temperature and CO₂ did not synergistically promote the growth and photosynthetic capacity of C. jubata seedling. The increase of temperature will greatly affect the growth and antioxidant system of C. jubata. The elevated CO₂ can only partially alleviate these adverse effects by increasing antioxidant levels. Therefore, future climate change, especially the increase in temperature, will have a greater impact on alpine shrub. The elevated CO₂ will alleviate the adverse effects of warming.





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