Soil C, N and P cycling enzyme responses to nutrient limitation under elevated CO2
Soil C, N and P cycling enzyme responses to nutrient limitation under elevated CO2
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DOI：
10.1007/s10533-020-00723-1
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发表时间：
2020-11
期刊：
影响因子：
4
通讯作者：
J. Keane;M. Hoosbeek;Christopher R. Taylor;F. Miglietta;G. Phoenix;I. Hartley
中科院分区：
文献类型：
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作者：
J. Keane;M. Hoosbeek;Christopher R. Taylor;F. Miglietta;G. Phoenix;I. Hartley
CO2浓度升高可以刺激植物生产力，增加土壤碳输入，但养分限制限制了生产力。尽管全球范围内磷（P）限制型生态系统的数量不断增加，但营养物质循环，特别是土壤微生物胞外酶活性（EEA）如何对此类生态系统中的eCO 2作出响应尚不清楚。从相邻的P-有限的酸性和石灰石草原长期养分操作地块暴露于eCO 2（600 ppm）提供的一个小型自由空气CO2富集系统。磷限制缓解（35 kg-P ha− 1 y −1（P35））、加剧（35 kg-N ha− 1 y −1（N35）、140 kg-N ha− 1 y −1（N140））或维持（对照（P0 N 0））超过20年。我们测量了C-、N-和P-循环酶（1，4-β-葡萄糖苷酶、纤维二糖水解酶、N-乙酰β-D-氨基葡萄糖苷酶、亮氨酸氨肽酶和酸性磷酸酶）的EEA，并使用矢量分析比较了C：N：P循环酶的比例。潜在的酸性磷酸酶活性增加了一倍，氮添加相对于P0 N 0和P35处理。矢量分析表明，减少碳循环投资和增加磷循环投资eCO 2。矢量角随P限制而显著增加（P35 <P0 N 0 < N35 < N140），表明P循环酶的投资相对较大。石灰岩草原是更C限制比酸性草原，其特征在于增加载体长度，C：N和C：P酶的比例。草地类型和eCO 2或营养处理的所有酶指标之间的相互作用的情况下，标志着一致的反应，改变P-限制和eCO 2在两个草原。我们的研究结果表明，eCO 2减少了碳限制，允许增加对P-和N-循环酶的投资，并对养分循环速率产生影响，可能缓解eCO 2下生态系统生产力的养分限制。
AbstractElevated CO2(eCO2) can stimulate plant productivity and increase carbon (C) input to soils, but nutrient limitation restricts productivity. Despite phosphorus (P)-limited ecosystems increasing globally, it is unknown how nutrient cycling, particularly soil microbial extra cellular enzyme activity (EEA), will respond to eCO2in such ecosystems. Long-term nutrient manipulation plots from adjacent P-limited acidic and limestone grasslands were exposed to eCO2(600 ppm) provided by a mini-Free Air CO2Enrichment system. P-limitation was alleviated (35 kg-P ha−1y−1(P35)), exacerbated (35 kg-N ha−1y−1(N35), 140 kg-N ha−1y−1(N140)), or maintained (control (P0N0)) for > 20 years. We measured EEAs of C-, N- and P-cycling enzymes (1,4-β-glucosidase, cellobiohydrolase, N-acetyl β-D-glucosaminidase, leucine aminopeptidase, and acid phosphatase) and compared C:N:P cycling enzyme ratios using a vector analysis. Potential acid phosphatase activity doubled under N additions relative to P0N0 and P35 treatments. Vector analysis revealed reduced C-cycling investment and increased P-cycling investment under eCO2. Vector angle significantly increased with P-limitation (P35 < P0N0 < N35 < N140) indicating relatively greater investment in P-cycling enzymes. The limestone grassland was more C limited than the acidic grassland, characterised by increased vector length, C:N and C:P enzyme ratios. The absence of interactions between grassland type and eCO2or nutrient treatment for all enzyme indicators signaled consistent responses to changing P-limitation and eCO2in both grasslands. Our findings suggest that eCO2reduces C limitation, allowing increased investment in P- and N-cycle enzymes with implications for rates of nutrient cycling, potentially alleviating nutrient limitation of ecosystem productivity under eCO2.Graphic abstract