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| Stomatal ozone flux-response relationships of rice(Oryza sativa L.) in subtropical area |
| Received:April 28, 2016 |
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| KeyWord:stomatal conductance;rice(Oryza sativa L.);ozone;flux-response relationship |
| Author Name | Affiliation | E-mail | | ZHANG Ji-shuang | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
University of Chinese Academy of Sciences, Beijing 100049, China | | | TANG Hao-ye | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | LIU Gang | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | | | ZHU Jian-guo | State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China | jgzhu@issas.ac.cn |
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| Abstract: |
| Based on previous investigations on a fully open-air ozone(O3) fumigation experiment(O3-FACE), we established dose-response relationships using O3 dose index AOT40(accumulated [O3] above 40 nL·L-1) and PODY(phytotoxic O3 dose, accumulated stomatal flux of O3 above a threshold of Y nmol·m-2·s-1), and compared their performance on O3-induced rice yield loss evaluation. The aim of this study is to find the optimum threshold for exposure-based and flux-based dose-response relationships used for ozone risk assessment on rice. Our result showed that the R2-value of regression analysis increased with flux threshold Y[0~11 nmol O3·m-2 PLA·s-1(PLA:projected leaf area)] and exposure threshold X(0~50 nL·L-1) increase, respectively. When flux threshold Y was 11 nmol O3·m-2 PLA·s-1 and exposure threshold X was 50 nL·L-1, the O3 dose index POD11 and AOT50 had the strongest correlation with RY(relative yield) of rice, respectively. High R2-value was derived i.e. 0.70~0.75 and 0.70~0.745 when flux threshold Y was within the range of 8~13 nmol O3·m-2 PLA·s-1 and exposure threshold X was 46~58 nL·L-1, respectively. Previous studies have indicated that the rice yield loss caused by near-surface ozone pollution may range from 5% to 8%. These results were similar with our estimation on ambient[O3] treatment using POD9~10 and AOT40~45. The higher R2-value 0.73~0.74 with POD9~10 compared to that of 0.64~0.69 with AOT40~45 indicated that flux-based assessment may have a superior performance on O3-induced rice yield loss estimation. Further analysis found that when flux threshold Y=9 nmol O3·m-2 PLA·s-1, assessment of rice yield loss was more accurate, and the R2-value(0.73) was higher than that of POD6(0.57). Our results suggested that POD9 is suitable for evaluating rice yield loss due to O3 increase in subtropical area. |
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