大气CO2浓度倍增对宁夏枸杞根区土壤微生物与酶活性的影响

为探究大气CO₂浓度倍增对宁夏枸杞根区土壤微环境的影响,以宁夏枸杞为试验材料,用开顶气室模拟控制CO₂浓度测得在大气CO₂浓度倍增处理下根区土壤微生物数量与土壤酶活性的变化。大气CO₂浓度倍增处理降低真菌数量,增加细菌、放线菌数量。0.5倍增CO₂浓度处理下宁夏枸杞根区土壤过氧化氢酶和转化酶的活性较对照分别提高24.74%和23.71%,脲酶活性和多酚氧化酶活性降低0.45%和15.29%;1倍增处理下土壤3种酶的活性较对照分别提高55.74%,23.07%,44.60%,而多酚氧化酶降低24.94%。通径分析表明,真菌数量对脲酶活性影响力最大,而细菌数量对过氧化氢酶活性影响力最强。大气CO₂浓度倍增宁夏枸杞根区土壤微生物数量与酶活性的相关性增强,其中真菌数量和细菌数量与脲酶呈显著负相关,放线菌数量在0.5倍增处理下与脲酶呈显著负相关。大气CO₂浓度倍增处理使宁夏枸杞根区土壤细菌、放线菌数量增加且可提高土壤过氧化氢酶、脲酶和转化酶的活性。

Elevated CO2 Concentrations: Effects on Soil Microbial Quantity and Enzyme Activity in Root Zone of Lycium barbarum

To investigate the effect of atmospheric CO₂ concentration on the soil microenvironment of wolfberry root area in Ningxia, Lycium barbarum L. was used as the test material, and the open-top air chamber was used to simulate the control of CO₂ concentration to measure the changes in the number of soil microorganisms and soil enzyme activity in the root zone under the double treatment of atmospheric CO₂ concentration. Elevated CO₂ concentration reduced the number of fungi and increased the number of bacteria and actinomycetes. Under 0.5-fold increase CO₂ concentration treatment, the activities of catalase and invertase in wolfberry root area were increased by 24.74% and 23.71%, the urease activity and polyphenol oxidase activity were decreased by 0.45% and 15.29% compared with those of the control. Under double CO₂ concentration treatment, the activities of the three enzymes were increased by 55.74%, 23.07%, and 44.60%, while the polyphenol oxidase decreased by 24.94%. Path analysis showed that the number of fungi had the greatest influence on urease activity, while the number of bacteria had the strongest influence on catalase activity. Atmospheric CO₂ concentration enhanced the correlation between the number of soil microorganisms and enzyme activity in the root zone, in which the number of fungi and bacteria was significantly and negatively correlated with urease, and the number of actinomycetes was significantly and negatively correlated with urease under 0.5-fold treatment. The elevated CO₂ concentration could increase the number of soil bacteria and actinomycetes in the root zone of wolfberry and the activities of soil catalase, urease and invertase.