氮添加对不同林龄华北落叶松叶片氮重吸收过程的影响  

Effect of nitrogen addition on leaf nitrogen resorption of Larix principis-rupprechtii plantations with different ages

作　　者：张文 闫涛 常文静 曾辉 ZHANG Wen;YAN Tao;CHANG Wen-jing;ZENG Hui(School of Urban Planning and Design,Peking University Shenzhen Graduate School,Shenzhen 518055,Guangdong,China;College of Urban and Environmental Sciences,Peking University,Beijing 100871,China)

机构地区：[1]北京大学深圳研究生院城市规划与设计学院,深圳518055 [2]北京大学城市与环境学院,北京100871

出　　处：《生态学杂志》2018年第12期3525-3532,共8页Chinese Journal of Ecology

基　　金：国家自然科学基金项目(31321061)资助

摘　　要：在全球氮沉降日益加剧的背景下,研究氮添加对不同林龄人工林叶片氮重吸收效率的影响有助于理解森林生态系统对气候变化的响应。本研究以华北落叶松(Larix principis-rupprechtii)人工林为对象,分析不同氮添加水平(0、20、50 kg N·hm^(-2)·a^(-1))对11、20和45年生华北落叶松人工林叶片干重、体积、氮含量以及氮重吸收效率的影响。结果表明:华北落叶松衰老前叶片干重和衰老后叶片干重均随林龄增大而显著减小(P<0.05);叶片衰老过程中,20年生华北落叶松叶片衰老后干重减少量显著大于11年生和45年生(P<0.01);11年生和20年生华北落叶松的衰老前叶片体积和衰老后体积减少量大于45年生(P<0.01)。外源氮添加显著减少了11年生华北落叶松林衰老前叶片体积(P<0.05);11年生华北落叶松叶片重吸收效率显著低于20年生和45年生(P<0.001),外源氮添加对11年生华北落叶松重吸收效率的减小作用显著大于20年生和45年生(P<0.01)。以上研究结果对准确评估森林生态系统氮循环及进一步了解森林生态系统生长策略有重要意义。Under the context of increasing nitrogen (N)deposition,studies on the effects of N addition on leaf N resorption of plantations with different ages could improve our understanding of the response of forest ecosystems to climate changes.In this study,we explored the effects of dif- ferent N addition levels (noN added as control,CK;20kg N·hm^-2·a^-1 as low N addition, N20;50kg N ·hm^-2·a^-1 as high N addition,NS0)on leaf dry mass,leaf volume,leaf N con- centration and N resorption efficiency (NRE)of Larix principis-rupprechtii with different ages (i.e.S11,S20and S45represented 11-,20-and 45-year-old stand,respectively).The results showed that the dry mass of both green and senescent leaves decreased with increasing stand ages (P<0.05).During the leaf senescence,the loss of leaf dry mass in S20was significantly greater than those of S11and S45(P<0.01).The loss of leaf volume in S45was significantly lower than those in S20and Sll.N addition significantly decreased the volume of green leaf in Sll before senescence (P<0.05).Leaf N resorption efficiency of S11was significantly lower than those of S20and S45(P<0.001).Furthermore,the reduction of NRE caused by N addition in Sll was significantly larger than the corresponding values in S20and S45(P<0.01).Our results are important for accurate assessment of N cycle in forest ecosystem and better understanding of growth strategies of forest ecosystems.

关 键 词：氮重吸收 林龄 氮沉降 叶片衰老 

分 类 号：S791.22[农业科学—林木遗传育种]