Zeng Quanchao, Liu Yang, An Shaoshan
College of Natural Resources and Environment, Northwest A&F University, Yangling, China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, China.
PeerJ. 2017 Sep 7;5:e3777. doi: 10.7717/peerj.3777. eCollection 2017.
The forest ecosystem is the main component of terrestrial ecosystems. The global climate and the functions and processes of soil microbes in the ecosystem are all influenced by litter decomposition. The effects of litter decomposition on the abundance of soil microorganisms remain unknown. Here, we analyzed soil bacterial communities during the litter decomposition process in an incubation experiment under treatment with different litter quantities based on annual litterfall data (normal quantity, 200 g/(m/yr); double quantity, 400 g/(m/yr) and control, no litter). The results showed that litter quantity had significant effects on soil carbon fractions, nitrogen fractions, and bacterial community compositions, but significant differences were not found in the soil bacterial diversity. The normal litter quantity enhanced the relative abundance of Actinobacteria and Firmicutes and reduced the relative abundance of Bacteroidetes, Plantctomycets and Nitrospiare. The Beta-, Gamma-, and Deltaproteobacteria were significantly less abundant in the normal quantity litter addition treatment, and were subsequently more abundant in the double quantity litter addition treatment. The bacterial communities transitioned from Proteobacteria-dominant (Beta-, Gamma-, and Delta) to Actinobacteria-dominant during the decomposition of the normal quantity of litter. A cluster analysis showed that the double litter treatment and the control had similar bacterial community compositions. These results suggested that the double quantity litter limited the shift of the soil bacterial community. Our results indicate that litter decomposition alters bacterial dynamics under the accumulation of litter during the vegetation restoration process, which provides important significant guidelines for the management of forest ecosystems.
森林生态系统是陆地生态系统的主要组成部分。全球气候以及生态系统中土壤微生物的功能和过程均受凋落物分解的影响。凋落物分解对土壤微生物丰度的影响尚不清楚。在此，我们基于年凋落物数据（正常量，200 g/(m²/年)；双倍量，400 g/(m²/年)），在不同凋落物量处理的培养实验中分析了凋落物分解过程中的土壤细菌群落，对照组无凋落物。结果表明，凋落物量对土壤碳组分、氮组分和细菌群落组成有显著影响，但土壤细菌多样性未发现显著差异。正常凋落物量增加了放线菌和厚壁菌门的相对丰度，降低了拟杆菌门、浮霉菌门和硝化螺旋菌门的相对丰度。在正常量凋落物添加处理中，β-、γ-和δ-变形菌纲的丰度显著较低，而在双倍量凋落物添加处理中随后丰度更高。在正常量凋落物分解过程中，细菌群落从以变形菌纲（β-、γ-和δ-）为主转变为以放线菌为主。聚类分析表明，双倍凋落物处理和对照组具有相似的细菌群落组成。这些结果表明，双倍量凋落物限制了土壤细菌群落的转变。我们的结果表明，在植被恢复过程中，凋落物分解在凋落物积累下改变了细菌动态，这为森林生态系统管理提供了重要的指导方针。
