State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing 100085, China; Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan.
State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Shuangqing Road 18, Haidian District, Beijing 100085, China.
Sci Total Environ. 2016 Dec 1;572:404-411. doi: 10.1016/j.scitotenv.2016.08.083. Epub 2016 Aug 17.
Five modern cultivars of winter wheat (Triticum aestivum L.): Yangmai16 (Y16), Yangmai 15 (Y15), Yangfumai 2 (Y2), Yannong 19 (Y19) and Jiaxing 002 (J2) were investigated to determine the impacts of elevated ozone concentration (E-O) on photosynthesis-related parameters and the antioxidant system under fully open-air field conditions in China. The plants were exposed to E-O at 1.5 times the ambient ozone concentration (A-O) from the initiation of tillering to final harvest. Pigments, gas exchange rates, chlorophyll a fluorescence, antioxidants contents, antioxidative enzyme activity and lipid oxidation were measured in three replicated plots throughout flag leaf development. Results showed that significant O effects on most variables were only found during the mid-grain filling stage. Across five cultivars, E-O significantly accelerated leaf senescence, as indicated by increased lipid oxidation as well as faster declines in pigment amounts and photosynthetic rates. The lower photosynthetic rates were mainly due to non-stomatal factors, e.g. lower maximum carboxylation capacity and electron transport rates. There were strong interactions between O and cultivar in photosynthetic pigments, light-saturated photosynthesis rate and chlorophyll a fluorescence with O-sensitive (Y19, Y2 and Y15) and O-tolerant (J2, Y16) cultivars being clearly differentiated in their responses to E-O. E-O significantly influenced the antioxidative enzymes but not antioxidant contents. Significant interactions between O and cultivar were found in antioxidative enzymes, such as SOD and CAT, but not in stomatal conductance (g). Therefore, it can be concluded that antioxidative enzymes rather than g or antioxidants are responsible for the differential responses to E-O among cultivars. These findings provide important information for the development of accurate modeling O effects on crops, especially with respect to the developmental stage when O damage to photosynthesis becomes manifest.
五种冬小麦现代品种（Triticum aestivum L.）：扬麦 16（Y16）、扬麦 15（Y15）、扬辐麦 2（Y2）、烟农 19（Y19）和嘉祥 002（J2），在我国完全开放的田间条件下，研究了高浓度臭氧（E-O）对光合作用相关参数和抗氧化系统的影响。从分蘖开始到最终收获，植物暴露在 1.5 倍大气臭氧浓度（A-O）的 E-O 下。在三叶期至成熟期间，对三个重复试验小区的叶片进行了色素、气体交换率、叶绿素 a 荧光、抗氧化剂含量、抗氧化酶活性和脂质氧化的测定。结果表明，在灌浆中期，E-O 对大多数变量的影响显著。在五个品种中，E-O 显著加速了叶片衰老，表现为脂质氧化增加以及色素和光合速率更快下降。较低的光合速率主要是由于非气孔因素，例如最大羧化能力和电子传递速率降低。O 与品种之间在光合色素、光饱和光合作用速率和叶绿素 a 荧光方面存在强烈的互作，对 O 敏感的（Y19、Y2 和 Y15）和 O 耐受的（J2、Y16）品种对 E-O 的响应明显不同。E-O 显著影响抗氧化酶，但不影响抗氧化剂含量。在抗氧化酶方面，如 SOD 和 CAT，发现 O 与品种之间存在显著的相互作用，但在气孔导度（g）方面则没有。因此，可以得出结论，抗氧化酶而不是 g 或抗氧化剂是导致品种对 E-O 产生不同响应的原因。这些发现为准确模拟作物对 O 影响提供了重要信息，特别是在光合作用受到 O 损害的发育阶段。
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