Deng Qi, Hui Dafeng, Luo Yiqi, Elser James, Wang Ying-ping, Loladze Irakli, Zhang Quanfa, Dennis Sam
Ecology. 2015 Dec;96(12):3354-62. doi: 10.1890/15-0217.1.
Increasing atmospheric CO2 concentrations generally alter element stoichiometry in plants. However, a comprehensive evaluation of the elevated CO2 impact on plant nitrogen: phosphorus (N:P) ratios and the underlying mechanism has not been conducted. We synthesized the results from 112 previously published studies using meta-analysis to evaluate the effects of elevated CO2 on the N:P ratio of terrestrial plants and to explore the underlying mechanism based on plant growth and soil P dynamics. Our results show that terrestrial plants grown under elevated CO2 had lower N:P ratios in both above- and belowground biomass across different ecosystem types. The response ratio for plant N:P was negatively correlated with the response ratio for plant growth in croplands and grasslands, and showed a stronger relationship for P than for N. In addition, the CO2-induced down-regulation of plant N:P was accompanied by 19.3% and 4.2% increases in soil phosphatase activity and labile P, respectively, and a 10.1% decrease in total soil P. Our results show that down-regulation of plant N:P under elevated CO2 corresponds with accelerated soil P cycling. These findings should be useful for better understanding of terrestrial plant stoichiometry in response to elevated CO2 and of the underlying mechanisms affecting nutrient dynamics under climate change.
大气中二氧化碳浓度的增加通常会改变植物体内的元素化学计量比。然而，尚未对二氧化碳浓度升高对植物氮磷比（N:P）的影响及其潜在机制进行全面评估。我们通过荟萃分析综合了112项先前发表的研究结果，以评估二氧化碳浓度升高对陆生植物N:P比的影响，并基于植物生长和土壤磷动态探索其潜在机制。我们的结果表明，在不同生态系统类型中，生长在高二氧化碳浓度下的陆生植物地上和地下生物量的N:P比均较低。在农田和草地中，植物N:P的响应比与植物生长的响应比呈负相关，且与磷的关系比与氮的关系更强。此外，二氧化碳诱导的植物N:P下调分别伴随着土壤磷酸酶活性和活性磷增加19.3%和4.2%，以及土壤总磷减少10.1%。我们的结果表明，高二氧化碳浓度下植物N:P的下调与土壤磷循环加速相对应。这些发现有助于更好地理解陆生植物对二氧化碳浓度升高的化学计量响应以及气候变化下影响养分动态的潜在机制。
