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利用亚洲首个开放式臭氧浓度升高平台(O3FACE),以臭氧敏感品种烟农19和臭氧耐性品种扬麦16为试材,研究了小麦光合特性对O3浓度升高的响应,并分析了不同敏感型小麦品种响应差异的可能原因。结果表明,O3浓度升高并持续处理75d,小麦旗叶的净光合速率(Pn)、气孔导度(Gs)和蒸腾速率(Tr)均显著下降,其中扬麦16的降幅(27.9%、37.5%和27.9%)明显小于烟农19(61.1%、68.0%和57.4%);而Ci基本维持恒定。说明O3FACE下小麦旗叶Pn下降是气孔因素和非气孔因素共同作用的结果,其中非气孔因素起决定性作用。叶绿素荧光分析表明,两个品种的PSII最大光化学量子产量(Fv/Fm)、PSII潜在活性(Fv/Fo)、光化学猝灭(qP)和光化学反应速率(Prate)等荧光参数均呈下降趋势,而非光化学猝灭(NPQ)和热耗散速率(Drate)呈上升趋势;可溶性蛋白和核酮糖-1,5-二磷酸羧化酶/加氧酶(Rubisco)则与荧光参数及Pn的变化趋势一致。由此可见,RuBP的羧化限制和PSII光系统损伤可能是O3胁迫下小麦旗叶Pn下降的主要非气孔因素。此外,O3FACE下扬麦16各参数的变幅均小于烟农19,扬麦16较高的蒸腾速率和较小的Rubisco含量降幅可能是其维持光合机构功能的重要原因。
Using O3FACE, the first open platform for increasing ozone concentration in Asia, the responses of ozone-sensitive cultivar Yannong 19 and ozone-tolerant cultivar Yangmai 16 were studied. The responses of wheat photosynthetic characteristics to elevated O3 concentrations were analyzed. Possible Responses of Wheat Varieties to Different Responses. The results showed that the net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) of wheat flag leaf decreased significantly with the increase of O3 concentration for 75 days. The decrease of Yangmai 16 (27.9%, 37.5 % And 27.9% respectively) were significantly lower than that of tobacco farmers 19 (61.1%, 68.0% and 57.4%), while Ci remained essentially constant. The decrease of Pn in wheat flag leaf under O3FACE is the result of the combination of stomatal and non-stomatal factors, and the non-stomatal factor plays a decisive role. The chlorophyll fluorescence analysis showed that the fluorescence parameters such as PSII maximum photochemical quantum yield (Fv / Fm), PSII potential activity (Fv / Fo), photochemical quenching (qP) and photochemical reaction rate (Prate) While non-photochemical quenching (NPQ) and heat dissipation rate (Drate) tended to increase. Soluble protein and ribulose-1,5-bisphosphate carboxylase / oxygenase (Rubisco) The same trend. Thus, carboxylation of RuBP and PSII light system damage may be the main non-stomatal factors of Pn decline in wheat flag leaf under O3 stress. In addition, the variation of each parameter of O3FACE is less than that of Yannong19. The higher transpiration rate and the smaller decrease of Rubisco content may be the important reasons for its function of maintaining photosynthetic apparatus.