酚酸和氮素交互作用下欧美杨107细根形态特征  

Interactive effects of phenolic acid and nitrogen on morphological traits of poplar(Populus × euramericana ‘Neva') fine roots

作　　者：朱婉芮 汪其同 刘梦玲[1] 王华田[1,2] 王延平[1,2] 张光灿[1,2] 李传荣[1,2] 

机构地区：[1]山东农业大学林学院,山东泰安271018 [2]国家林业局泰山森林生态系统定位研究站,山东泰安271018

出　　处：《植物生态学报》2015年第12期1198-1208,共11页Chinese Journal of Plant Ecology

基　　金：国家重点基础研究发展计划项目(2012-CB416904);国家自然科学基金(31170662和31270670);山东省自然科学基金(ZR2012CM033);山东省博士后创新基金(2014140687)

摘　　要：树木细根生长与根际过程的关系十分密切。该研究仿生欧美杨107(Populus×euramericana‘Neva’)人工林根际土壤酚酸沉降与氮素有效性变化,通过设置3种酚酸梯度(0X、0.5X、1.0X,X为田间土壤酚酸含量)与3种氮素水平(缺氮0 mmol·L^(–1)、正常氮10 mmol·L^(–1)、高氮20 mmol·L^(–1)),探究酚酸和氮素对欧美杨107细根形态的影响,以期为阐明树木根系生长对根-土界面过程的响应奠定基础。结果表明:(1)在无酚酸(0X)环境中,缺氮和高氮均可抑制欧美杨107细根生长,尤其对1–3级细根的影响更为显著。比根长随氮素水平升高逐渐减小,但其他细根特征并未呈现与氮素水平的线性关系。(2)0.5X和1.0X酚酸梯度相比,欧美杨107的1–2级细根直径和体积随酚酸浓度增加而显著增大(p<0.05)。酚酸和氮素对杨树细根的影响存在交互作用,1–2级细根直径、体积受酚酸的影响显著,而4–5级细根长度、表面积受氮素影响显著。双因素方差分析结果表明,酚酸和氮素对细根形态建成具有协同或拮抗效应。(3)主成分分析(PCA)和冗余分析(RDA)结果表明,在酚酸和氮素交互效应下,杨树1–3级、4级、5级细根之间具有显著的形态差异。第一主成分主要体现细根觅食性状特征,可解释细根形态变异的60.9%的信息;第二主成分主要体现细根形态构建特征,可解释25.3%的信息。杨树细根形态变化与根序高度相关,N素影响杨树细根形态的主效应较酚酸更强。因此,根际环境中酚酸累积和氮素有效性变化会影响杨树细根的形态构建和细根对水分、养分的吸收,而氮素有效性是影响杨树细根生长的重要因素,开展杨树人工林土壤养分管理是林分生产力长期维持的关键。Aims The relationship between rhizosphere process and fine root growth is very close but still obscure. In poplar plantation, phenolic acid rhizodeposition and soil nutrient availability were considered as two dominant factors of forest productivity decline. It is very hard to separate them in the field and they might show an interactive effect on fine root growth. The objective of this study is to examine the influence of phenolic acids and nitrogen on branch orders of poplar fine roots and to give a deeper insight into how the ecological process on root-soil interface affected fine root growth as well as plantation productivity. Methods The cuttings of health annual poplar seedlings（I-107, Populus × euramericana ‘Neva＇） serve as experiment materials, and were cultivated under nine conditions, including three concentration of phenolic acids at 0X, 0.5X, 1.0X（here, X represented the contents of phenolic acids in the soil of poplar plantation） and three concentration of nitrogen at 0 mmol·L^–1, 10 mmol·L^–1, 20 mmol·L^–1, based on Hoagland solution. The roots were all separated from poplar seedlings after 35 days, and 30 percent of total fine roots of every treatment were taken as fine root samples. These fine roots were grouped according to 1 to 5 branch orders, and then the morphological traits of each group of fine roots were scanned via root analyzer system（Win RHIZO, Regent Instruments Company, Quebec, Canada） including total length, surface area, volume and average diameter. Meanwhile, the dry mass of fine root samples of every order was measured to calculate specific root length（SRL）, root tissue density（RTD）. All data were analyzed via SPSS 17.0 software, and interactive effect of phenolic acids and nitrogen on roots was analyzed through univariate process module. Principal component analysis（PCA） and redundancy analysis（RDA） were conducted via Canoco 4.5 software. Important findings Under the conditions without phenolic acids application, the fine roots growth was

关 键 词：细根形态 氮素有效性 酚酸根际沉降 杨树根序 根土互作 

分 类 号：S792.11[农业科学—林木遗传育种]