亚热带杉木人工林土壤胞外酶活性对隔离降雨的季节响应  

Seasonal response of extracellular enzyme activity to precipitation exclusion in a subtropical Cunninghamia lanceolata plantation

作　　者：倪梦颖 张秋芳[1,2] 高金涛 郑永[1,2] 周嘉聪 陈岳民[1,2] 杨玉盛 NI Mengying1,2, ZHANG Qiufang1,2, GAO Jintao1,2 , ZHENG Yong1,2, ZHOU Jiacong1,2 , CHEN Yuemin1,2, YANG Yusheng1,2(1 School of Geographical Sciences, Fujian Normal University, Fuzhou 350007, China 2 Cultivation Base of State Key Laboratory of Humid Subtropical Mountain Ecology, Fuzhou 350007, Chin)

机构地区：[1]福建师范大学地理科学学院,福州350007 [2]湿润亚热带山地生态国家重点实验室培育基地,福州350007

出　　处：《生态学报》2018年第6期2119-2127,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金项目(31670620);海峡联合基金项目(U1505233);福建省科技厅项目(2016R1032-2)

摘　　要：土壤酶在养分矿化过程中起着至关重要的作用,是预测土壤向植物提供养分能力的特殊传感器。土壤酶的催化、生产和降解速率受水分调节,而全球气候变暖所引起的降水减少将对中亚热带地区森林生态系统造成深刻影响,但是关于中亚热带杉木人工林土壤酶活性对降水变化响应的研究还是相对匮乏。通过隔离降雨模拟实验减少50%的降水,探究干湿两季中亚热带杉木人工林表层土壤的理化性质、胞外酶活性和有效养分对降水减少的响应。研究的胞外酶有:参与碳循环的β-葡萄糖苷酶(βG)、纤维素水解酶(CBH)、酚氧化酶(PHO)、过氧化物酶(PEO)。冗余分析结果显示:干季时的土壤酶活性主要是受土壤含水量、硝态氮和可溶性有机碳(DOC)的影响,湿季则主要受微生物量碳、DOC和铵态氮的影响。湿季的土壤酶活性总体大于干季的土壤酶活性。除了干季的酚氧化酶外,无论干季或是湿季,几乎所有土壤酶活性在降水减少后均有所提高,其中βG活性变化最为显著。这可能是因为中亚热带地区降水丰富,尽管进行了隔离降雨处理,但水分仍然未达到限制水平;也可能是酶活性对降水减少这种不利的环境变化做出的响应或适应策略。本研究也为未来气候变化降水减少下对预测碳循环和养分循环提供了一定的科学依据。Soil enzymes play an essential role in nutrient mineralization and their activity is an exceptional indicator for predicting the capacity of soil to supply nutrients to plants. In soil organic matter decomposition,soil extracellular enzymes catalyze the rate-limiting step and their catalysis,production,and degradation rates are regulated by moisture. Due to global warming,precipitation in the mid-subtropical region is decreasing,which profoundly affects the forest ecosystems; however,research in this field is relatively scarce. To investigate how soil extracellular enzyme activity（ EEA） responds to altered precipitation regime,we conducted this study to measure the effects of experimental reduction in rainfall by 50% on the soil physicochemical properties, extracellular enzyme activity, and nutrient availability in surface soil samples from a Cunninghamia lanceolata forest ecosystem,collected in dry and wet seasons. These extracellular enzymes were carbonacquisition enzymes,including β-glucosidase（ βG）,cellulose hydrolysis（ CBH）,phenol oxidase（ PHO）,and peroxidase（PEO）. The results showed that the overall enzyme activities of the wet season samples were higher than those of the dry season samples. Irrespective of the season,except for PHO in the dry season samples,the activities of almost all soil enzymes,especially βG,significantly increased after treatment. Redundancy analysis indicated that the EEA patterns were mainly driven by soil moisture,NO^3-N,and dissolved organic carbon（ DOC） in the dry season,and by microbial biomass carbon,DOC,and NH4^＋-N in the wet season. Our results suggested that the EEA in the carbon cycle in the mid-subtropical region would increase with reduction in precipitation. This may be because,despite the precipitation exclusion experiment,moisture did not become a limiting factor owing to the high rainfall in the mid-subtropical region. Alternatively,it could be a response or adaptation strategy of EEA to the adverse environmental change of precipitation re

关 键 词：酶活性 隔离降雨 干湿季 杉木 

分 类 号：S714[农业科学—林学]