增温与氮添加对不同季节杉木幼苗细根不同形态氮吸收动力学的影响  

Effects of warming and nitrogen addition on nitrogen uptake kinetics of fine roots of Cunninghamia lanceolata seedlings in different seasons

作　　者：姜琦 郭润泉 宋涛涛 陈廷廷 陈宇辉 贾林巧 熊德成[1,2] 陈光水[1,2] JIANG Qi;GUO Runquan;SONG Taotao;CHEN Tingting;CHEN Yuhui;JIA Linqiao;XIONG Decheng;CHEN Guangshui(School of Geographical Science,Fujian Normal University,Fuzhou 350007,China;Key Laboratory for Humid Subtropical Eco⁃Geographical Processes of the Ministry of Education,Fujian Normal University,Fuzhou 350007,China)

机构地区：[1]福建师范大学地理科学学院,福州350007 [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350007

出　　处：《生态学报》2020年第9期2996-3005,共10页Acta Ecologica Sinica

基　　金：国家自然科学基金重点项目(31830014)。

摘　　要：为了揭示不同季节下杉木人工林不同形态氮吸收速率对全球变暖与氮沉降的地下响应,在福建三明森林生态系统与全球变化研究站陈大观测点开展增温和氮添加双因子试验,包括对照、增温、施氮、增温+施氮4个处理。结果表明:(1)在三个季节中,4个处理的杉木细根对不同浓度下硝态氮的吸收速率基本呈现出春季较高,夏秋季较低的态势,而对不同浓度下铵态氮的吸收速率则相反,为夏秋季较高,春季较低。(2)不同季节四个处理的离体根对不同浓度下铵态氮的吸收均遵循米氏⁃曼氏动力学方程,而对硝态氮的吸收并不完全遵循米氏方程,表现为双相动力学。(3)春季,与无氮添加相比,氮添加提高了NH4^+的最大吸收速率(Vmax⁃NH4^+)。夏季,与无增温相比,增温提高了Vmax⁃NH4^+。秋季,与无增温相比,增温降低了NH4^+的半饱和常数(Km⁃NH4^+);与无氮添加相比,氮添加提高了Km⁃NH4^+。增温与氮添加对不同季节100μmol时的硝态氮吸收速率(V100⁃NO-3)都没有显著影响。增温与氮添加对不同季节Vmax⁃NH4^+、Km⁃NH4^+和V100⁃NO-3都没有显著的交互作用。本研究表明增温会提高杉木幼苗夏秋季的NH4^+吸收能力,而氮添加会提高春季的NH4^+吸收能力,降低秋季的NH4^+吸收能力,但增温与氮添加并不会改变不同季节的NO-3吸收能力。In order to reveal the influence of global warming and nitrogen addition on the ecological process of Chinese fir(Cunninghamia lanceolata)seedlings,we conducted a two⁃factor experiment of warming and nitrogen addition,which consisted control,warming,nitrogen addition,and warming+nitrogen addition.The study site is located in Forest Ecosystem and Global Change Research Station of Fujian Normal University in Chenda,Sanming,Fujian Province.The results showed that:(1)the absorption rate of nitrate nitrogen by the fine roots of C.lanceolata under different concentrations was higher in spring and lower in summer and autumn,but the absorption rate of ammonium nitrogen was higher in summer and autumn and lower in spring.(2)The absorption of ammonium nitrogen by the four treatments followed the Michaelis⁃Menten kinetic equation,but the absorption of nitrate nitrogen did not fully followed it,which showed dual⁃phase kinetics in different seasons.(3)In spring,compared with nitrogen⁃free addition,nitrogen addition increased the maximum velocity of NH4^+(Vmax⁃NH4^+).In summer,compared with no warming,the warming increased Vmax⁃NH4^+.In autumn,compared with no warming,the warming decreased the Michaelis⁃Menten constant(Km⁃NH4^+);compared with nitrogen⁃free addition,nitrogen addition increased Km⁃NH4^+.Warming and nitrogen addition had no significant effect on the absorption rate of nitrate nitrogen at 100μmol(V100⁃NO-3)in different seasons,and there was no significant interaction between warming and nitrogen addition on Vmax⁃NH4^+,Km⁃NH4^+ and V100⁃NO-3 in different seasons.The results indicated that warming would improve NH4^+ absorption capacity of Chinese fir seedlings in summer and nitrogen addition would improve NH4^+ absorption capacity in spring and reduce NH4^+ absorption capacity in autumn,but warming and nitrogen addition would not change NO-3 absorption capacity in different seasons.

关 键 词：氮吸收动力学 细根 增温 氮添加 

分 类 号：S791.27[农业科学—林木遗传育种]