Fine roots stimulate nutrient release during early stages of leaf litter decomposition in a Central Amazon rainforest-猫眼课题宝

DOI：

10.1007/s11104-021-05148-9

发表时间：

2021-10

期刊：

Plant and Soil

影响因子：

4.9

通讯作者：

中科院分区：

农林科学2区

文献类型：

作者：

N. Martins;Lucia Fuchslueger;K. Fleischer;K. Andersen;R. Assis;F. Baccaro;P. Camargo;A. Cordeiro;A. Grandis;I. Hartley;F. Hofhansl;L. F. Lugli;D. Lapola;J. Menezes;R. Norby;A. Rammig;J. S. Rosa;Karst J. Schaap;Bruno Takeshi;O. Valverde‐Barrantes;C. Quesada

亚马逊雨林的大部分地区生长在风化的土壤上，这些土壤缺乏磷和岩石衍生的阳离子。我们测试的假设，在这个生态系统中，细根刺激分解和养分释放从落叶生物化学释放酶，并通过渗出不稳定的碳刺激微生物decomposers.MethodsWe监测落叶分解在亚马逊热带雨林中部，细根要么存在或排除，在188天内，并在完全析因设计中加入不稳定的碳底物（葡萄糖和柠檬酸）。我们跟踪凋落物质量损失，剩余的碳，氮，磷和阳离子浓度，胞外酶活性和微生物的碳和养分concentrations.ResultsFine根的存在并没有影响凋落物质量损失，但显着增加了磷和阳离子的损失从落叶。在细根的存在下，酸性磷酸酶活性高出43.2%，而既不是微生物的化学计量，也不是胞外酶的活性，针对含碳和含氮化合物的变化。当细根存在时，添加葡萄糖会增加凋落物中磷的流失，并增强根排除物中的磷酸酶活性。柠檬酸添加减少凋落物质量损失，微生物生物量氮和磷，无论细根存在或exclusionsWe得出结论，植物根系释放大量的酸性磷酸酶到凋落物层和动员磷，而不影响凋落物质量损失。我们的研究结果进一步表明，增加不稳定的碳输入（即葡萄糖）可以刺激酸性磷酸酶的生产微生物分解，突出了热带森林生态系统中植物微生物反馈的潜在重要性。

PurposeLarge parts of the Amazon rainforest grow on weathered soils depleted in phosphorus and rock-derived cations. We tested the hypothesis that in this ecosystem, fine roots stimulate decomposition and nutrient release from leaf litter biochemically by releasing enzymes, and by exuding labile carbon stimulating microbial decomposers.MethodsWe monitored leaf litter decomposition in a Central Amazon tropical rainforest, where fine roots were either present or excluded, over 188 days and added labile carbon substrates (glucose and citric acid) in a fully factorial design. We tracked litter mass loss, remaining carbon, nitrogen, phosphorus and cation concentrations, extracellular enzyme activity and microbial carbon and nutrient concentrations.ResultsFine root presence did not affect litter mass loss but significantly increased the loss of phosphorus and cations from leaf litter. In the presence of fine roots, acid phosphatase activity was 43.2% higher, while neither microbial stoichiometry, nor extracellular enzyme activities targeting carbon- and nitrogen-containing compounds changed. Glucose additions increased phosphorus loss from litter when fine roots were present, and enhanced phosphatase activity in root exclusions. Citric acid additions reduced litter mass loss, microbial biomass nitrogen and phosphorus, regardless of fine root presence or exclusion.ConclusionsWe conclude that plant roots release significant amounts of acid phosphatases into the litter layer and mobilize phosphorus without affecting litter mass loss. Our results further indicate that added labile carbon inputs (i.e. glucose) can stimulate acid phosphatase production by microbial decomposers, highlighting the potential importance of plant-microbial feedbacks in tropical forest ecosystems.

Fine roots stimulate nutrient release during early stages of leaf litter decomposition in a Central Amazon rainforest

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