欧美杨107幼树叶片和细根的功能性状对臭氧剂量的响应  

Response of functional traits of leaves and fine roots of Populus euramericana cv.’74/76’saplings to ozone dose

作　　者：李品 侯霄帆 殷荣宾 Li Pin;Hou Xiaofan;Yin Rongbin(School of Forestry,Beijing Forestry University,Beijing 100083,China;State Key Laboratory of Urban and Regional Ecology,Research Centre for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China)

机构地区：[1]北京林业大学林学院,北京100083 [2]中国科学院生态环境研究中心城市与区域生态国家重点实验室,北京100085

出　　处：《北京林业大学学报》2023年第2期49-57,共9页Journal of Beijing Forestry University

基　　金：中央高校基本科研业务费专项(2021ZY07);国家自然科学基金项目(31870458)。

摘　　要：【目的】杨树的叶和细根在森林生态系统碳和养分(如氮、磷等)循环中起核心作用,但目前细根对臭氧(O_(3))胁迫响应的研究还较缺乏,尚不清楚叶和细根对O_(3)胁迫的响应差异。本研究旨在阐明叶片和细根这2个快速分解器官对O_(3)剂量的响应差异,为从植物地上-地下反馈角度理解杨树对O_(3)污染的响应机制提供科学参考。【方法】本研究采用开顶室气室装置设置5个O_(3)浓度水平,研究杨树叶片和细根功能性状指标对O_(3)剂量的响应是否存在差异。【结果】叶片单宁和细根磷含量表现出显著的兴奋效应,即毒性阈值之前为应激正效应,毒性阈值之后为抑制负效应。叶片饱和光合速率、细根生物量以及叶片和细根可溶性糖含量出现毒性阈值,但未观察到显著兴奋效应。水分利用效率以及叶、茎、粗根和总根生物量对O_(3)剂量呈现线性胁迫下降响应。碳、氮、可溶性糖、木质素含量以及木质素∶氮内稳性较强,沿O_(3)浓度梯度在叶片和细根中的分配未发生变化。磷、淀粉和总非结构性碳水化合物随O_(3)浓度升高分配到细根的比例增加;单宁表现为分配到叶片的比例先增加,当O_(3)剂量达到37.25μmol/mol·h时,分配到细根的比例增加。【结论】杨树叶片和细根的功能性状对O_(3)剂量存在响应差异。O_(3)胁迫增加了杨树细根中P和非结构性碳水化合物的储存比例,这可能是植物抵御O_(3)胁迫的一种应对策略。[Objective]Poplar leaves and fine roots play a key role in the carbon and nutrient cycle(such as nitrogen and phosphorus)in the forest ecosystem.However,the response of fine roots to ozone(O_(3))stress has been poorly studied,and the difference in responses of leaves and fine roots to O_(3)is still unclear.This study thus aimed to clarify the difference in responses to O_(3)dose of leaves and fine roots,two rapidly decomposing organs,and to provide reference for understanding the response mechanism of poplar to O_(3)pollution from the perspective of aboveground and belowground feedback.[Method]Five O_(3)concentration levels were set with the open-top chambers to explore whether the functional traits of poplar leaves and fine roots respond differently to O_(3)dose.[Result]There was significant hormesis on the response of tannin content of leaves and P content of fine roots to O_(3)stress,which showed a positive effect before toxicological O_(3)threshold and a negative effect after toxicological O_(3)threshold.Leaf saturated photosynthetic rate,fine root biomass and soluble sugar content of leaves and fine roots showed a toxicological O_(3)threshold,but not significant hormesis.Water use efficiency and the biomass of leaves,stems,coarse roots and total roots decreased linearly with O_(3)dose increasing.The ratio of fine roots to leaves in the content of C,N,soluble sugar,lignin,and lignin∶N did not change with O_(3)dose increasing.The ratio of fine roots to leaves in the content of P,starch,and TNC increased with the O_(3)dose increasing,while tannin content first declined and then rose with O_(3)dose increasing(O_(3)threshold value of 37.25μmol/mol·h).[Conclusion]These results indicate that the significant differences in the responses of leaves and fine roots to O_(3)pollution will result in marked changes in the relative belowground roles of these two litter sources within poplar plantations.O_(3)stress could induce more P and non-structural carbohydrates to fine roots for storage relative to leaves,which mig

关 键 词：臭氧胁迫 杨树107 细根 叶片 功能性状 剂量响应 

分 类 号：S792.26[农业科学—林木遗传育种] Q948[农业科学—林学]