凋落物输入下土壤酶活性及其化学计量的季节性变化  

Seasonal Changes of Soil Enzymatic Activities and Stoichiometry Under Litter Input

作　　者：卿婷 艾灵 吴福忠 朱晶晶 倪祥银 QING Ting;AI Ling;WU Fuzhong;ZHU Jingjing;NI Xiangyin(School of Geographical Sciences,School of Carbon Neutrality Future Technology,Fujian Normal University,Fuzhou 350117,China;Key Laboratory for Humid Subtropical Eco-Geographical Process of the Ministry of Education,Fujian Normal University,Fuzhou 350117,China;Sanming Forest Ecosystem National Observation and Research Station,Sanming 365002,China)

机构地区：[1]福建师范大学地理科学学院,碳中和未来技术学院,福州350117 [2]福建师范大学湿润亚热带生态-地理过程教育部重点实验室,福州350117 [3]福建三明森林生态系统国家野外科学观测研究站,福建三明365002

出　　处：《亚热带资源与环境学报》2025年第1期126-135,共10页Journal of Subtropical Resources and Environment

基　　金：国家自然科学基金项目(32022056)。

摘　　要：土壤酶是凋落物中养分释放的重要参与者,但土壤酶活性和酶化学计量对凋落物输入的响应在不同林龄次生林中随季节性时间的变化仍不明晰。以亚热带9年和45年生米槠次生林为研究对象,通过原位微宇宙实验来研究短期凋落物输入后,土壤α-1,4-葡萄糖苷酶(AG)、β-1,4-葡萄糖苷酶(BG)、纤维二糖水解酶(CBH)、木聚糖酶(XS)、β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)、脲酶(UR)和酸性磷酸酶(AP)活性随季节性时间的变化趋势。结果表明,短期凋落物输入后,只有土壤AG活性显著降低,并且在9年生次生林中的下降幅度大于45年。土壤酶活性对季节性时间变化具有显著响应,在9年生次生林中,凋落物输入后土壤AG活性在5月、7月、8月和12月分别下降58%、29%、22%和26%,土壤XS和CBH活性分别在6月和7月分别下降16%和32%,土壤UR和AP活性在10月分别下降40%和23%。在45年生次生林中,土壤AG活性在4月和5月分别下降34%和38%,土壤CBH和UR活性分别在5月和7月下降51%和15%。此外,酶向量特征表明,随着季节性时间的推移,9年和45年生次生林中土壤微生物的养分限制从相对磷限制(4~8月)转变为相对氮限制(10~12月)。土壤碳氮磷获取酶活性比ln(BG)∶ln(LAP+NAG)∶ln(AP)分别为1∶2.16∶2.19和1∶2.09∶2.14,偏离了全球尺度上1∶1∶1的比例,表明氮和磷可能是两种林龄次生林中土壤微生物的主要限制元素。在短期凋落物输入下,土壤酶化学计量比与对应的土壤碳氮磷化学计量比相关性较低,两者之间不耦合。冗余分析表明土壤微生物生物量磷和溶解有机碳浓度分别是影响9年生和45年生次生林土壤酶活性和化学计量变化的主要因子。综上,与凋落物输入和林龄变化相比,土壤酶活性可能更多地受季节性波动的调节。Soil enzymes play a crucial role in nutrient release from litter.However,how soil enzyme activity and enzyme stoichiometry respond to litter input over seasonal time in secondary forests of differentstand ages remains unclear.This study used an in situ microcosm experiment to explore seasonal variations in the activities of soilα-1,4-glucosidase(AG),β-1,4-glucosidase(BG),cellobiohydrolase(CBH),xylanase(XS),β-1,4-N-acetylaminoglucosidase(NAG),leucine aminopeptidase(LAP),urease(UR)and acid phosphatase(AP)activities in 9-year-old and 45-year-oldCastanopsis carlesiisecondary forests following short-term litter input.The results showed that AG activity was the only enzyme significantly reduced after litter input,with a greater decline observed in the 9-year-old forest compared to the 45-year-old forest.Soil enzyme activities exhibited significant responses to seasonal changes.In the 9-year-old forest,AG activity decreased by 58%,29%,22%,and 26%in May,July,August,and December,respectively.Additionally,XS and CBH activities declined by 16%and 32%in June and July,respectively,while UR and AP activities decreased by 40%and 23%in October.In the 45-year-old forest,AG activity dropped by 34%and 38%in April and May,respectively,and CBH and UR activities decreased by 51%and 15%in May and July,respectively.Moreover,Vector angle indicated that soil microbial nutrient limitation shifted from relative phosphorus limitation(April-August)to relative nitrogen limitation(October-December)over the seasonal cycle.The enzymatic stoichiometric ratios of soil carbon,nitrogen,and phosphorus acquisition,ln(BG)∶ln(LAP+NAG)∶ln(AP),were 1∶2.16∶2.19 and 1∶2.09∶2.14 in the 9-and 45-year-old forests,respectively.These ratios deviated from the global 1∶1∶1 pattern,suggesting that nitrogen and phosphorus were likely the primary limiting nutrients for soil microorganisms in both forest stands.Under short-term litter input,soil enzymatic stoichiometry was weakly correlated with soil carbon,nitrogen,and phosphorus stoichiometry,indic

关 键 词：土壤酶活性 酶化学计量 凋落物输入 次生林 

分 类 号：S714.3[农业科学—林学]