臭氧对不同年代推广的冬小麦光合作用和生长的影响

毕斯沃斯 许宏 李永庚 马宝林 蒋高明*

*通讯作者

中国科学院植物学研究所植被与环境变化国家重点实验室，中国北京香山南辛村20号，100093

实验植物学报, 2013, 64(6): 1485-1496. （影响因子：5.345） 

【摘要】 二氧化碳升高对植物光合的有益影响，将受到其它全球变化所带来的负面影响所抵消，不同O3敏感性植物对于臭氧（O3）的响应，尤其在高CO2环境下的调节还知之甚少。本文研究了老品种小麦（北京6号，耐臭氧型）和现代品种（中麦9号，O3敏感型）暴露于CO2（714ppm）和O3（72ppb，7h d-1）中，在开顶室同化箱( OTC)中培养21d后的光合生理与生长变化。通过观察叶片症状、测定气体交换和叶绿素a荧光、体内生化特性和生长来评估植株对不同处理的反应。结果表明，与老品种相比，现代品种对CO2浓度升高表现为较高的能量捕获和电子传输速率。与老品种相比，现代品种由于更高的O3吸收和更大的光系统II效率（成熟叶）和叶肉细胞活性（幼叶）损失，而导致更大的生长减少。在高CO2和O3条件下，尽管高CO2保护了两个品种免受O3危害，但现代品种比老品种表现出更高的O3吸收和更大的O3光抑制，从而导致高CO2诱导的生长刺激相对损失。该研究结果表明，在CO2和O3浓度升高前提下，由于较高的能量捕获和电子传输速率，现代品种CO2诱导的生长刺激可能会受到其较高的O3吸收和更大的光抑制而影响。

Modification of photosynthesis and growth responses to elevated CO2 by ozone in two cultivars of winter wheat with different years of release

D. K. Biswas, H. Xu, Y.G. Li, B.L. Ma, G.M. Jiang*

State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, The Chinese Academy of Sciences, 20 Nanxincun, 100093 Beijing, PR China.

Journal of Experimental Botany, 2013, 64(6): 1485-1496. （IF=5.345）

Abstract: The beneficial effects of elevated CO2 on plants are expected to be compromised by the negative effects posed by other global changes. However, little is known about ozone (O3)-induced modulation of elevated CO2 response in plants with differential sensitivity to O3. An old (Triticum aestivum cv. Beijing 6, O3 tolerant) and a modern (T. aestivum cv. Zhongmai 9, O3 sensitive) winter wheat cultivar were exposed to elevated CO2 (714 ppm) and/or O3 (72 ppb, for 7h d(-1)) in open-topped chambers for 21 d. Plant responses to treatments were assessed by visible leaf symptoms, simultaneous measurements of gas exchange and chlorophyll a fluorescence, in vivo biochemical properties, and growth. It was found that elevated CO2 resulted in higher growth stimulation in the modern cultivar attributed to a higher energy capture and electron transport rate compared with the old cultivar. Exposure to O3 caused a greater growth reduction in the modern cultivar due to higher O3 uptake and a greater loss of photosystem II efficiency (mature leaf) and mesophyll cell activity (young leaf) than in the old cultivar. Elevated CO2 completely protected both cultivars against the deleterious effects of O3 under elevated CO2 and O3. The modern cultivar showed a greater relative loss of elevated CO2-induced growth stimulation due to higher O3 uptake and greater O3-induced photoinhibition than the old cultivar at elevated CO2 and O3. Our findings suggest that the elevated CO2-induced growth stimulation in the modern cultivar attributed to higher energy capture and electron transport rate can be compromised by its higher O3 uptake and greater O3-induced photoinhibition under elevated CO2 and O3 exposure.