凋落物输入对根系分泌物碳输入及土壤氮的影响  

Effect of litter input on root exudative carbon input and rhizosphere nitrogen

作　　者：张成富 赵庆霞 蔡银美 李昕颖 何腾兵[1,2] ZHANG Chengfu;ZHAO Qingxia;CAI Yinmei;LI Xinying;HE Tengbing(College of Agriculture,Guizhou University,Guiyang,Guizhou 550025,China;Institute of New Rural Development,Guizhou University,Guiyang,Guizhou 550025,China)

机构地区：[1]贵州大学农学院,贵州贵阳550025 [2]贵州大学新农村发展研究院,贵州贵阳550025

出　　处：《森林与环境学报》2021年第3期263-271,共9页Journal of Forest and Environment

基　　金：国家自然科学基金地区基金项目(32060339);贵州省科技厅联合基金项目(黔科合LH字[2017]7277);贵州省科技厅基础条件平台建设项目(黔科合平台人才[2019]5701号);贵州省林业青年项目(黔林科合J(2018)06号);贵州大学引进人才科研项目(贵大人基合字(2017)68号)。

摘　　要：以马尾松人工林及林下灌木短柱茶为研究对象,采用根系分泌物原位收集法,分析凋落物处理[对照(保持原状凋落物不变,CK)、去除凋落物(LR)、添加凋落物(LA)]对两树种根系分泌物碳输入速率、根际土壤氮含量和氮转化相关酶活性的影响,并分析其相关关系。结果表明:凋落物输入量变化对马尾松和短柱茶根系分泌物碳输入速率无显著影响。同一凋落物处理下,马尾松和短柱茶根系分泌物碳输入速率无显著差异。凋落物输入量变化不显著影响根际土壤氮含量及马尾松根际土壤脲酶、羟胺还原酶、硝酸还原酶和亚硝酸还原酶活性,短柱茶根际土壤硝酸还原酶活性表现为去除凋落物处理显著大于对照,其余氮转化相关酶活性未表现出显著差异。可能是凋落物处理时间较短,凋落物未完全分解或者是林分年龄较大有关。相关关系结果表明,单位根长根系分泌物碳输入速率与根际土壤全氮(TN)含量呈显著负相关关系,单位根表面积根系分泌物碳输入速率与根际土壤硝态氮含量(NO-3-N)含量呈显著负相关关系。表明根系分泌物碳输入与根际土壤氮素相互影响。This study investigated these interactions by focusing on the Pinus massoniana plantation and its understory shrub Camellia brevistyla.The effects of intact litter maintenance,litter removal,and litter addition on root exudative carbon input rate,rhizosphere nitrogen content,and nitrogen conversion-related enzyme activities were analyzed by in-situ root exudate sampling and analyzing correlations.The results showed that the change in litter input had no significant effect on the root exudative carbon input rate of Pinus massoniana and Camellia brevistyla.Under the same litter treatment,there was no significant difference observed in the root exudative carbon input rate between the two tree species.Litter treatment did not significantly affect the rhizosphere soil nitrogen content,urease,hydroxylamine reductase,nitrate reductase,and the nitrite reductase activities of Pinus massoniana.The nitrate reductase activity of Camellia brevistyla showed that the effect of litter removal was greater than that of the control;the other three enzyme activities did not significantly differ between treatments.These results may be attributable to the short experimental time,incomplete decomposition of the litter,or the relatively old tree stand age.Correlation analyses showed that the root exudative carbon input rate per unit root length was significantly negatively correlated with the total nitrogen in the rhizosphere.Additionally,the root exudative carbon input rate per unit root surface area was significantly negatively correlated with NO-3-N in the rhizosphere.This indicates that the carbon inputs of root exudates interact with nitrogen in the rhizosphere.

关 键 词：马尾松 短柱茶 凋落物 根系分泌物 氮 

分 类 号：S714[农业科学—林学]