中文关键词臭氧氮沉降干旱非结构性碳水化合物细根杨树 英文关键词O₃nitrogen depositiondrought stressnon-structural carbohydratesfine rootspoplar

作者	单位	E-mail
李品	北京林业大学林学院, 北京 100083	lipin@bjfu.edu.cn
周慧敏	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
冯兆忠	南京信息工程大学应用气象学院, 南京 210044

中文摘要 快速城市化和工业化进程，导致植物生长季常暴露于高浓度地表臭氧（O₃）、干旱和氮（N）沉降的环境中.为探究植物非结构性碳水化合物（NSC）及其组分（可溶性糖和淀粉）对多重环境因子胁迫的响应格局，本实验设置2个O₃处理（对照，以过滤空气计；增加O₃，未过滤空气+40 nmol·mol^-1 O₃）、2个水分处理（充分灌溉；干旱，60%灌溉）和2个N添加处理［不加氮；加氮，50 kg·（hm²·a）^-1尿素］，研究三因子交互作用对杨树叶片和细根NSC及其组分的影响.结果表明，O₃胁迫显著增加杨树叶片可溶性糖和细根淀粉含量，降低叶片淀粉和总NSC含量.干旱胁迫显著降低叶片淀粉和总NSC含量，增加细根可溶性糖和总NSC含量.氮添加对叶和细根NSC及其组分无显著影响.叶片和细根NSC及其组分与光合速率、生物量存在显著正相关关系.随着胁迫因子数量的增加，叶片NSC呈现下降趋势，而细根NSC呈现上升趋势.本研究发现环境胁迫可促使植物叶片中的淀粉转化为可溶性糖，并将叶片中的NSC转移到根部储藏，这可能是植物抵御胁迫环境的一种应对策略. 英文摘要 Ground-level ozone (O₃) pollution frequently co-occurs with drought and nitrogen (N) deposition during the growing season. It is important to understand how the carbon dynamics of plants respond to O₃ pollution in drier and N-enriched environments. Here we present the patterns of non-structural carbohydrates and its components (soluble sugar and starch) in the leaves and fine roots in poplar clone 546 (Populus deltoides cv. ‘55/56’×P. deltoides cv. ‘Imperial’) for one growing season at two O₃ concentrations (control, charcoal-filtered air, and elevated O₃, non-filtered air+40 nmol·mol^-1 of O₃), two watering regimes (well-watered and reduced watering at 40% of well-watered irrigation), and two soil nitrogen addition treatments[no addition and the addition of 50 kg·(hm²·a)^-1]. The results showed that O₃ stress significantly increased the content of soluble sugar in leaves and starch in fine roots but decreased the content of starch and total non-structural carbohydrate (NSC) in leaves. Drought stress significantly reduced the content of starch and total NSC in leaves but increased the contents of soluble sugar and total NSC in fine roots. Nitrogen addition had no significant effect on NSC and its components in leaves and fine roots. NSC and its components in leaves and fine roots were positively correlated with photosynthetic rate and biomass. With an increase in the number of environmental stress factors, NSC in leaves showed a significant downward trend while NSC in fine roots showed a significant upward trend. The study demonstrates that environmental stress can promote the transformation of starch into soluble sugars in plant leaves and the transfer of NSC from leaves to roots for storage, which may be a coping strategy for plants exposed to environmental stress.

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