摘要
土壤胞外酶活性是催化土壤有机质分解的关键限速步骤,而且对外界环境的变化极其敏感,然而却很少有研究聚焦于土壤胞外酶活性对气候变化的响应,尤其是在黄土高原地区.以黄土丘陵区撂荒草地为研究对象,野外模拟气候变暖和降水增加,通过测定土壤理化性质、植被群落特征和土壤酶活性,探究土壤酶活性及计量比对气候变化的响应特征及驱动因素.结果表明,增温、增雨以及二者的交互作用均显著降低了土壤β-1,4-葡糖苷酶(BG)和纤维二糖水解酶(CBH)活性,然而,土壤β-1,4-木糖苷酶(BX)活性在气候变化处理下却呈现出增加趋势,其中,增温处理的增幅最大,达到了63.15%.增温增雨的交互显著增加了β-1,4-N-乙酰氨基葡萄糖苷酶(NAG)和亮氨酸胺肽酶(LAP)以及碱性磷酸酶(ALP)活性,分别增加了34.32%、12.97%和44.86%.增温显著增加了过氧化物酶(PER)活性,而增雨显著降低了PER酶活性,增雨以及增温增雨显著降低了多酚氧化酶(PPO)活性,这主要归因于植物群落科组成的变化.增雨和增温增雨处理下碳降解酶活性∶氮降解酶活性(CEs∶NEs)和氮降解酶活性∶磷降解酶活性(NEs∶PEs)显著降低,而碳降解酶活性∶磷降解酶活性(CEs∶PEs)在增温、增雨及其交互作用下均显著降低,增雨以及增温增雨处理下土壤酶化学计量的向量长度均低于对照处理,且向量角度均大于对照处理,表明土壤微生物在暖湿条件下的碳限制和氮限制程度有所减弱.主成分分析和冗余分析结果表明土壤水分含量和土壤有机碳含量是引起酶活性及计量特征变化的主要驱动因子.综上所述,气候变化下黄土丘陵区撂荒草地植被群落科组成的变化,尤其是木质素含量较低且具有固氮能力的豆科植物数量的增加以及土壤有机碳含量的增加会减弱土壤微生物的碳氮限制,研究结果可为理解脆弱生境地区在气候变化背景下土壤微生物的养分限制情况提供依据.
Soil extracellular enzyme activities(EEA)catalyze the key rate-limiting step in the decomposition of soil organic matter and are extremely sensitive to changes in environmental factors.However,few studies have focused on the response of soil EEA to climate change,especially in the Loess Plateau.To explore the response characteristics and driving factors of soil EEA and enzymatic stoichiometry of abandoned grassland in the Loess hilly area under the conditions of climate warming and increasing precipitation,the physical and chemical properties of the soil,vegetation community,and EEA were determined.The results showed that warming(W),increased precipitation(P),and their interaction(WP)significantly reduced soilβ-1,4-glucosidase(BG)enzyme and cellobiosidase(CBH)activities.However,the activity ofβ-1,4-xylosidase(BX)showed an increasing trend under the climate change treatment.Among them,the W treatment reached 63.15%.The WP treatment significantly increased the activities ofβ-1,4-N-acetylglucosaminidase(NAG),leucine aminopeptidase(LAP),and alkaline phosphatase(ALP)by 34.32%,12.97%,and 44.86%,respectively.The analysis of soil oxidase activity found that W significantly increased peroxidase(PER)activity,whereas increased P significantly reduced PER enzyme activity,and P and WP significantly reduced phenol oxidase(PPO)activity,mainly due to changes in the composition of the plant community.CEs∶NEs and NEs∶PEs were significantly reduced under the P and WP treatments,and CEs∶PEs was significantly reduced under W,P,and WP.The vector lengths of the soil enzymatic stoichiometry under the W,P,and WP treatments were both lower than those of the control treatment,and the vector angle was larger than that of the control treatment,indicating that the carbon limitation and nitrogen limitation of soil microbial communities under W and increased P conditions were weakened.The results of principal component analysis and redundancy analysis indicated that the soil moisture content and soil organic carbon content were the main driving factors causing changes in EEA and enzymatic stoichiometry.In summary,the conditions of climate change led to changes in the family composition of the vegetation community of the abandoned grassland in the Loess hilly region,especially the increase in the number of legumes with low lignin content and the ability to fix nitrogen.Additionally,the increase in soil organic carbon content weakened the carbon and nitrogen limitations of soil microbial communities.These results provide a basis for understanding the carbon,nitrogen,and phosphorus requirements and limitations of soil microbial communities in fragile ecosystems under the background of climate change.
作者
王兴
钟泽坤
简俊楠
张硕宏
杨改河
任成杰
冯永忠
任广鑫
王晓娇
韩新辉
WANG Xing;ZHONG Ze-kun;JIAN Jun-nan;ZHANG Shuo-hong;YANG Gai-he;REN Cheng-jie;FENG Yong-zhong;REN Guang-xin;WANG Xiao-jiao;HAN Xin-hui(College of Agronomy,Northwest A&F University,Yangling 712100,China;Shaanxi Engineering Research Center of Circular Agriculture,Yangling 712100,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2022年第5期2812-2821,共10页
Environmental Science
基金
国家林业和草原局林草科技创新发展与研究项目(2020132111)
国家自然科学基金项目(41907031)。
关键词
气候变化
撂荒草地
土壤胞外酶活性
酶计量比
养分需求和限制
climate change
abandoned grassland
soil extracellular enzyme activity
enzymatic stoichiometry
nutrient requirements and limitations
