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    李品, 侯霄帆, 殷荣宾. 欧美杨107幼树叶片和细根的功能性状对臭氧剂量的响应[J]. 北京林业大学学报, 2023, 45(2): 49-57. DOI: 10.12171/j.1000-1522.20210347
    引用本文: 李品, 侯霄帆, 殷荣宾. 欧美杨107幼树叶片和细根的功能性状对臭氧剂量的响应[J]. 北京林业大学学报, 2023, 45(2): 49-57. DOI: 10.12171/j.1000-1522.20210347
    Li Pin, Hou Xiaofan, Yin Rongbin. Response of functional traits of leaves and fine roots of Populus euramericana cv. ‘74/76’ saplings to ozone dose[J]. Journal of Beijing Forestry University, 2023, 45(2): 49-57. DOI: 10.12171/j.1000-1522.20210347
    Citation: Li Pin, Hou Xiaofan, Yin Rongbin. Response of functional traits of leaves and fine roots of Populus euramericana cv. ‘74/76’ saplings to ozone dose[J]. Journal of Beijing Forestry University, 2023, 45(2): 49-57. DOI: 10.12171/j.1000-1522.20210347

    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

    • 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(O3)胁迫响应的研究还较缺乏,尚不清楚叶和细根对O3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O3剂量的响应差异,为从植物地上-地下反馈角度理解杨树对O3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O3浓度水平,研究杨树叶片和细根功能性状指标对O3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O3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O3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O3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O3剂量达到37.25 μmol/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O3剂量存在响应差异。O3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O3胁迫的一种应对策略。

       

      Abstract:
        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 (O3) stress has been poorly studied, and the difference in responses of leaves and fine roots to O3 is still unclear. This study thus aimed to clarify the difference in responses to O3 dose of leaves and fine roots, two rapidly decomposing organs, and to provide reference for understanding the response mechanism of poplar to O3 pollution from the perspective of aboveground and belowground feedback.
        Method  Five O3 concentration levels were set with the open-top chambers to explore whether the functional traits of poplar leaves and fine roots respond differently to O3 dose.
        Result  There was significant hormesis on the response of tannin content of leaves and P content of fine roots to O3 stress, which showed a positive effect before toxicological O3 threshold and a negative effect after toxicological O3 threshold. Leaf saturated photosynthetic rate, fine root biomass and soluble sugar content of leaves and fine roots showed a toxicological O3 threshold, but not significant hormesis. Water use efficiency and the biomass of leaves, stems, coarse roots and total roots decreased linearly with O3 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 O3 dose increasing. The ratio of fine roots to leaves in the content of P, starch, and TNC increased with the O3 dose increasing, while tannin content first declined and then rose with O3 dose increasing (O3 threshold value of 37.25 μmol/mol·h).
        Conclusion  These results indicate that the significant differences in the responses of leaves and fine roots to O3 pollution will result in marked changes in the relative belowground roles of these two litter sources within poplar plantations. O3 stress could induce more P and non-structural carbohydrates to fine roots for storage relative to leaves, which might be a coping strategy for poplar exposed to O3 stress.

       

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