Plant and Soil ( IF 4.9 ) Pub Date : 2022-05-27 , DOI: 10.1007/s11104-022-05499-x Xiangsheng Deng, Fei Cheng, Mingman Li, Peng He, Lu Shen, Haiyu Liu
Aims
The effect of Eucalyptus stump substrate decomposition on microbial resource limitation driving factors are unclear.
Methods
Eucalyptus stump substrate samples from five decay classes with contrasting qualities were decomposed in Eucalyptus undergrowth soil for three months in a laboratory microcosm experiment. We determined the substrate quality, microbial biomass, microbial community structure, and extracellular enzyme activities for the decay classes of stump substrates.
Results
The stump carbon:nitrogen (C:N), carbon:phosphorus (C:P), and nitrogen:phosphorus (N:P) ratios and dissolved organic carbon:total dissolved nitrogen (DOC:TDN), dissolved organic carbon:available phosphorus (DOC:AP), and total dissolved nitrogen:available phosphorus (TDN:AP) ratios increased and then decreased as the decay class increased, whereas the C:N and C:P imbalances between the microorganisms inhabiting stumps and their resources increased. The activities of N- and P-acquiring enzymes improved as the decay class increased, and such changes improved the microbial N and P limitation of stumps and reduced the microbial C use efficiency. In advanced decay classes, the microbial community structure shifted toward a higher ratio of fungi to bacteria and a lower ratio of gram-positive bacteria to gram-negative bacteria. Redundancy analysis showed that P, DOC, and DOC:AP were all closely related to the enzyme activities, whereas P and N were the critical factors alter microbial composition community. In addition, ecoenzymatic stoichiometry and the C:N:P imbalance played key roles on regulating microbial C use efficiency.
Conclusions
The decomposition of Eucalyptus stump substrates modified microbial communities and enzymatic stoichiometry, leading to microbial growth from P limitation to N limitation.
中文翻译:
桉树桩底不同腐烂等级对微生物资源限制和碳利用效率的影响
目标
桉树桩底物分解对微生物资源限制驱动因素的影响尚不清楚。
方法
在实验室缩影实验中,来自五个腐烂等级的桉树树桩基质样品在桉树下生长的土壤中分解了三个月。我们确定了树桩底物腐烂类别的底物质量、微生物生物量、微生物群落结构和细胞外酶活性。
结果
树桩碳:氮 (C:N)、碳:磷 (C:P) 和氮:磷 (N:P) 比率和溶解有机碳:总溶解氮 (DOC:TDN)、溶解有机碳:有效磷(DOC:AP)和总溶解氮:有效磷(TDN:AP)比率随着腐烂等级的增加而增加然后减少,而栖息在树桩上的微生物及其资源之间的C:N和C:P不平衡增加。N-和P-获取酶的活性随着腐烂等级的增加而提高,并且这种变化改善了树桩的微生物N和P限制并降低了微生物C利用效率。在高级腐烂等级中,微生物群落结构转向更高的真菌与细菌比例和更低的革兰氏阳性细菌与革兰氏阴性细菌的比例。冗余分析表明,P、DOC 和 DOC:AP 都与酶活性密切相关,而 P 和 N 是改变微生物组成群落的关键因素。此外,生态酶化学计量和 C:N:P 失衡在调节微生物 C 利用效率方面发挥了关键作用。
结论
桉树桩底物的分解改变了微生物群落和酶化学计量,导致微生物从 P 限制生长到 N 限制。