作 者：
刘仁;张宇飞;金志芳;毛瑢;张扬;李晓东;陈伏生
单 位：
江西农业大学鄱阳湖流域森林生态系统保护与修复国家林业和草原局重点实验室;江西农业大学林学院江西省森林培育重点实验室;江西九连山国家级自然保护区管理局
关键词：
外源氮;气候变暖;毛竹;细根;重量损失;养分释放;酶活性
摘 要：
细根分解是毛竹(Phyllostachys edulis)林碳和养分归还的重要组成部分,但外源氮添加和温度如何共同影响毛竹细根分解及养分动态尚不清楚。本文通过360 d的微宇宙室内培养试验研究施氮(0和5 mg N·g-1细根)和温度(18和28℃)对细根分解过程中CO2累积释放量、重量损失、养分(N、P、Ca、Mg、Fe、Mn和Cu)浓度和残留量以及酶(酸性磷酸酶AP、葡萄糖苷酶BG、半纤维素酶CB、亮氨酸氨基肽酶LAP和乙酰氨基葡萄糖苷酶NAG)活性的影响。结果表明:CO2累积释放量、重量损失和酶活性均随着培养温度的增加而增加,而细根N、P浓度和残留量、P/Mn则呈现相反的趋势;施氮对毛竹细根分解及酶活性的影响随着培养温度的变化而存在差异,在28℃时施氮显著降低CO2累积释放量、重量损失、N/P、N/Mn、AP和BG活性,而在18℃时,施氮显著降低细根Mn浓度及残留量、N/Mn、BG和NAG活性。施氮和温度交互作用显著地影响0～180与0～360 d细根分解过程中CO2累积释放量、重量损失、AP和NAG活性。细根分解过程N浓度、N/Mn、P/Mn与AP、BG、NAG活性均呈显著负相关,而Mn浓度与BG、NAG活性呈显著正相关。可见,外源氮添加和温度通过共同影响酶活性调控毛竹细根分解速率及其养分归还量,研究结果为准确评估和预测全球变化背景下毛竹林碳和养分循环提供科学依据。
译 名：
Incubation temperature modulates the effects of exogenous nitrogen addition on decomposition and nutrient release of Phyllostachys edulis fine roots
作 者：
LIU Ren;ZHANG Yu-fei;JIN Zhi-fang;MAO Rong;ZHANG Yang;LI Xiao-dong;CHEN Fu-sheng;Jiangxi Provincial Key Laboratory of Silviculture,College of Forestry,Jiangxi Agricultural University;Key Laboratory of National Forestry and Grassland Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed,Jiangxi Agricultural University;Jiulianshan National Nature Reserve Administration in Jiangxi of China;
关键词：
exogenous nitrogen;;climate warming;;moso bamboo;;fine root;;mass loss;;nutrient release;;enzyme activity
摘 要：
Fine root decomposition is an important component of carbon and nutrient cycles in moso bamboo( Phyllostachys edulis) forests. However,how exogenous nitrogen addition and temperature interact to affect bamboo fine root decomposition and nutrient dynamics is still unclear.In this study,a 360-day microcosm incubation experiment was used to assess the effects of nitrogen addition( 0 and 5 mg·N g-1 root) and incubation temperature( 18 and 28 ℃) on cumulative CO2 production,mass loss,nutrients( N,P,Ca,Mg,Fe,Mn,and Cu) concentrations and remaining percentages,and enzyme activities during fine root decomposition. Our results showed that CO2 production,mass loss,and enzyme activities at 28 ℃ were significantly higher than those at 18 ℃,whereas N,P concentrations and remaining percentages,and P/Mn exhibited the reverse trend. The effects of nitrogen addition on bamboo fine root decomposition andenzyme activities varied with incubation temperature. Nitrogen addition significantly decreased cumulative CO2 production and mass loss,N/P,N/Mn,acid phosphatase( AP) and glycosidase enzymes( BG) activities at 28 ℃,but decreased Mn concentration and remaining percentage,N/Mn,BG and acetyl grape amine glycosidase( NAG) activities at 18 ℃ . Nitrogen addition and incubation temperature significantly interacted to affect cumulative CO2 production at 0-180 d and 0-360 d,mass loss,AP and BG activities. By the end of incubation,N concentration,N/Mn,and P/Mn in decomposing fine roots were negatively correlated with AP,BG and NAG activities,while Mn concentration was positively correlated with BG and NAG activities. These findings suggest that exogenous N addition and incubation temperature co-regulated fine root decomposition and nutrient releases via regulating enzyme activities. Our results would help accurately assess and predict ecosystem C and nutrient cycles in bamboo forests under the context of global change.
