铅镉胁迫下蚯蚓对土壤碳氮相关酶及微生物多样性的影响  

Effects of Earthworms on Soil Carbon and Nitrogen-related Enzymes and Microbial Diversity under Stress of Pb and Cd

作　　者：赵奕乔 罗庆睿 段昌群[1,2,3] 张悦 蔡粤[1,2,3] 刘嫦娥 ZHAO Yiqiao;LUO Qingrui;DUAN Changqun;ZHANG Yue;CAI Yue;LIU Chang’e(Yunnan Key Laboratory for Plateau Mountain Ecology and Restoration of Degraded Environments,School of Ecology and Environmental Sciences Yunnan University,Kunming 650091,China;Yunnan Field Scientific Station for Restoration of Ecological Function in Central Yunnan of China,Kunming 650091,China;International Cooperative Center of Plateau Lake Ecological Restoration and Watershed Management of Yunnan,Kunming 650091,China)

机构地区：[1]云南大学生态与环境学院,云南省高原山地生态与退化环境修复重点实验室,云南昆明650091 [2]滇中生态敏感区生态功能修复云南省野外科学观测研究站,云南昆明650091 [3]云南省高原湖泊生态修复及流域管理国际联合研究中心,云南昆明650091

出　　处：《环境科学与技术》2025年第2期1-11,共11页Environmental Science & Technology

基　　金：国家自然科学基金项目(32260315,32371707);云南省基础研究计划重点项目(202201AS070016,202201BF070001-002)。

摘　　要：凋落物分解是陆地生态系统中物质循环的关键环节,而重金属污染会影响与碳氮循环有关的酶的活性和微生物群落结构,进而改变凋落物分解速率。文章为探究蚯蚓介导杨树凋落叶分解对铅镉污染土壤酶活性及微生物多样性的影响,设置无(CK)、低(L)、中(M)、高(H)4种铅镉浓度与有(E)、无(N)蚯蚓添加,共8种处理组,同时在表面施加8.0 g杨树凋落叶,进行90 d盆栽试验。研究表明:铅镉胁迫抑制了蚯蚓对杨树凋落叶分解,第90天CK-E处理杨树凋落叶的分解速率最大;土壤有机碳(SOC)和总氮(TN)含量则随暴露时间延长呈增加趋势,均为第90天时CK-E处理含量最高,比CK-N分别显著增加了19.61%和7.40%;且在低、中浓度铅镉胁迫下,蚯蚓的存在增加了土壤SOC、TN含量。各处理组土壤中与碳循环相关的酶(β-葡萄糖苷酶(BG)、酚氧化酶(PO)、过氧化物酶(POD)、β-木糖苷酶(XYS))及与氮循环相关的酶(脲酶(UR)、亮氨酸氨基肽酶(LAP)、β-N-乙酰氨基葡糖苷酶(NAG))的活性均随铅镉污染浓度增大而降低;蚯蚓显著影响了土壤BG、POD、XYS和NAG活性,且提高了铅镉污染土壤微生物丰富度。此外,随着暴露时间延长及土壤铅镉浓度增加,土壤中绿弯菌门和担子菌门相对丰度增加。研究表明,蚯蚓介导可减轻重金属铅镉污染对土壤微生物活性的胁迫作用,会改变杨树凋落叶分解过程中BG、POD、XYS和NAG活性,改变释放的碳、氮的化学计量,进而影响土壤生态系统碳氮循环进程。该研究揭示铅镉污染条件下蚯蚓对杨树凋落叶分解状况、土壤碳氮相关酶活性及微生物多样性的影响,为正确评价蚯蚓在重金属污染土壤生态系统养分循环中的作用提供参考和理论支持。Litter decomposition is a key link in the material cycle of terrestrial ecosystems,and heavy metal pollution can greatly affect the activity of enzymes related to carbon and nitrogen cycling and the structure of microbial communities,thereby altering the rate of litter decomposition.To investigate the effects of earthworm-mediated decomposition of poplar leaf litter on the activity of enzymes related to carbon and nitrogen cycling and microbial diversity in lead-cadmium contami-nated soil,a pot experiment was conducted with eight treatments including no(CK),low(L),medium(M),and high(H)concentrations of lead and cadmium,as well as with the addition of earthworms(E)and without earthworms(N).A total of 8.0 g of poplar leaf litter was applied topically for 90 days.The results showed that lead and cadmium stress inhibited the decomposition of poplar leaf litter by earthworms.At day 90,CK-E treatment showed the highest decomposition rate of poplar leaves.The contents of soil organic carbon(SOC)and total nitrogen(TN)increased with exposure time,with the high-est content at day 90 in treatment CK-E,respectively,which were significantly increased by 19.61%and 7.40%compared to treatment CK-N(P<0.05).Under low and medium concentrations of lead and cadmium stress,earthworms increased the SOC and TN contents of the soil.The activities of enzymes related to carbon cycle(β-glucosidase(BG),phenol oxidase(PO),peroxidase(POD),β-xylosidase(XYS))and nitrogen cycle(urease(UR),leucine aminopeptidase(LAP),β-N-acetylglucosa-minidase(NAG))decreased with increasing lead and cadmium pollution concentrations.Earthworms significantly affected the activities of enzymes related to carbon cycle and nitrogen cycle,and increased the microbial richness of lead-cadmium contaminated soil.In addition,with the increase of exposure time and soil lead and cadmium concentrations,the relative abun-dance of Chloroflexi and Basidiomycota increased in the soil.The study showed that earthworm-mediated can alleviate the stress of heavy metal lead and cadmiu

关 键 词：重金属污染 养分循环 酶活性 蚯蚓 土壤微生物 

分 类 号：X53[环境科学与工程—环境工程]