模拟根系分泌物输入对高寒退化草地土壤微生物残体的影响

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 模拟根系分泌物输入对高寒退化草地土壤微生物残体的影响 DOI: 10.5846/stxb202108222343 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家科技部重点研发项目（2020YFE0203200）；第二次青藏高原综合科学考察研究项目（2019QZKK0302）；四川省科技厅项目（2020YFH0201，2020YFH0001） Effects of simulated root exudates input on soil microbial residues in the degraded alpine grassland Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:微生物残体是稳定土壤碳库的重要来源，对退化生境碳的固持和积累具有重要意义。植物根系分泌物作为植物-土壤-微生物"交流"的媒介，是调控土壤微生物残体迁移转化的关键。因此，以极度退化草地土壤为对象，以氨基糖为标志物，模拟研究了不同氮浓度（低氮-LN：0.1 gN/kg；高氮-HN：0.2 gN/kg）和多样性（3种化合物、9种化合物）根系分泌物输入对土壤微生物残体的影响。结果表明：（1）根系分泌物输入可显著增加高寒退化草地土壤微生物残体含量，且主要由真菌残体贡献。其中高氮和低多样性处理增加最明显，微生物残体和真菌残体分别增加了101.14%，125.16%，而低氮和高多样性处理微生物残体和真菌残体仅增加了35.79%，33.51%。（2）根系分泌物的输入可增加土壤β-葡萄糖苷酶、土壤磷酸酶和过氧化物酶活性，促进微生物的生长，而降低β-N-乙酰氨基葡萄糖苷酶活性，减少微生物残体的分解。（3）回归分析结果显示，土壤微生物残体与土壤环境的C/N呈显著负相关，与微生物生物量C/N呈显著正相关。上述结果表明，在未来退化草地恢复中，可充分利用模拟根系分泌物输入的土壤固碳策略，即通过提高土壤氮的有效性，促进微生物的生长，加快代谢周转，进一步提高微生物残体含量。 Abstract:Microbial residues are important sources for stabilizing soil carbon pools and are of great significance for carbon sequestration and accumulation in the degraded habitats. Plant root exudates, as the medium of plant-soil-microorganism linkages, play a key role in regulating the migration and transformation of soil microbial residues. In this study, we simulated the effects of different nitrogen concentrations (low nitrogen-LN:0.1 gN/kg; high nitrogen-HN:0.2 gN/kg) and diversities (3 compounds, 9 compounds) of root exudates on soil microbial residues in extremely degraded grassland soils with amino sugars as markers. The results showed that:(1) the input of root exudates significantly increased the content of soil microbial residues in alpine degraded grassland, which was mainly contributed by fungal residues. The microbial and fungal residues increased by 101.14% and 125.16% in the high nitrogen and low diversity treatments, respectively, while only increased by 35.79% and 33.51% in the low nitrogen and high diversity treatments. (2) The input of root exudates increased the activities of β-glucosidase, acid phosphatase and peroxidase in soil and promoted the growth of microorganisms, while decreased the activities of β-N-acetaminoglycosidase and reduced the decomposition of microbial residues. (3) Regression analysis showed that soil microbial residues were significantly negatively correlated with soil environment C/N, and significantly positively correlated with microbial biomass C/N. The results showed that the soil carbon sequestration strategy simulating the input of root exudates could be fully utilized in the future restoration of degraded grassland, which could promote microbial growth, accelerate metabolic turnover and further increase microbial residues content by improving the availability of soil nitrogen. 参考文献 相似文献 引证文献