中文关键词
地表臭氧生态风险粮食作物木本植物产量生物量 | 英文关键词ground-level ozoneecological riskcropwoody plantsyieldbiomass |
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| 中文摘要 |
| 当前我国地表臭氧（O3）污染日趋严重，对植物生产力构成了严重威胁.本文综述了粮食作物产量和木本植物生物量与O3暴露水平指标M7（7 h平均O3浓度，09：00~16：00）、SUM06（每小时O3浓度大于60 nmol·mol-1的累积值）、W126（每小时O3浓度在特定时段内用Sigmoidal函数加权求和值）、PODY［每小时气孔O3通量高于阈值Y nmol·（m2·s）-1的累积吸收通量］和最常用的AOT40（每小时O3浓度超过40 nmol·mol-1部分的累积值）之间的响应关系，并计算了相应的损伤阈值.基于AOT40的结果表明，导致水稻、冬小麦、玉米和大豆产量下降5%的O3风险阈值分别为5.93、2.69、8.67和4.17 μmol·mol-1·h，说明我国玉米对O3的耐受性可能要高于其它3种作物；对于木本植物，杨树5个品种的熏蒸实验和17种木本植物的整合分析的结果显示，导致其总生物量减少5%的O3风险阈值分别为12.20 μmol·mol-1·h和10.87 μmol·mol-1·h.此外，提出了未来相关研究应关注建立植物其它重要参数与O3污染的响应关系与提高O3区域风险评估精度，同时需要重点考虑如何将影响植物O3敏感性的重要因子（如土壤氮素和树龄等）耦合到区域评估模型中. |
| 英文摘要 |
| Currently, ground-level ozone (O3) pollution is increasingly serious in China, and highly threatens plant productivity. In this study, we summarized the relationship between relative crop yield or woody plant biomass and O3 metrics, including M7 (the mean of hourly concentrations from 09:00 to 16:00), SUM06 (sum of hourly concentrations above 60 nmol·mol-1), W126 (Sigmoidal weighted sum of the hourly concentrations during a specified period), PODY[phytotoxic O3 dose above a threshold flux of Y nmol·(m2·s)-1], and the most commonly used AOT40 (accumulated O3 concentrations over an hourly threshold of 40 nmol·mol-1), and proposed their critical level to protect plants against O3 damage. Based on the AOT40 metric, we found that the O3 risk threshold that caused a 5% decrease in yield was 5.93 μmol·mol-1·h for rice, 2.69 μmol·mol-1·h for winter wheat, 8.67 μmol·mol-1·h for maize, and 4.17 μmol·mol-1·h for soybean, indicating that maize may be more tolerant to O3 than the other three crops in China. The O3 risk threshold that led to a 5% reduction in total biomass was 12.20 μmol·mol-1·h across five poplar clones (based on experiment) and 10.87 μmol·mol-1·h across 17 woody plants (based on integrated analysis). On the other hand, some perspectives were presented concerning the establishment of O3 response relationships for important productivity-related parameters, and the improvement of accuracy in O3 regional risk assessment. It is also important to consider how to couple other important factors affecting plant O3 sensitivity (such as soil nitrogen and plant age) into the regional assessment model. |
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