摘要
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。
Ozone （O3） has been recognized as a secondary phytotoxic air pullutant of serious concern in agriculture because of its effects on the physiology, growth, and yield of plants. Although the effects of elevated O3 concentration on plant photosynthesis have widely studied with environment-controlled chambers, the conclusions are not certain due to the difference between free-air field and environment-controlled chambers. O3-Free Air Concentration Enrichment （O3FACE） can provide undisturbed field conditions and more reliable measurements in comparison with environment-controlled facilities. In this study, two winter wheat （Tritcium aestivum L.） cultivars （Yannong 19 and Yangmai 16） with different sensitivities to O3 were used to investigate the responses of photosynthsis characteristics to elevated O3 concentration with the Chinese O3FACE platform. Under O3 treatment for 75 d, the net photosynthetic rate （Pn）, stomtal conductance （Gs）, and transpiration rate （Tr） decreased significantly in both cultivars, whereas the intercellular CO2 concentration （Ci） changed slightly. This indicated that the reduction of Pnresulted from stomatal and nonstomal factors with the major role of nonstomatal. The O3-sensitive cultivar Yannong 19 showed larger reductions in Pn （61.1%）, Gs （68.0%）, and Tr （57.4%） than Yangmai 16 （27.9%, 37.5%, and 27.9%, respectively）. In the chlorophyll fluorescence parameters, the maximal photochemical efficiency of PSII in the dark （Fv/Fm）, the potential activity of PSII （Fv/Fo）, the photochemical quenching （qP）, and the rate of photochemical reaction （Prate） decreased in O3 treatment, but the nonphotochemical quenching （NPQ） and the rate of thermal dissipation （Drate） showed the upward tendency. The change tendency of total soluble protein content and the amount of Rubisco was similar to that of chlorophyll fluorescence parameters and Pn. The results implied that the major nonstomal factors responsible for Pn decrease under elevated O3 concentration were the carboxylation limitation of RuBP and the damage of PSII. The change extents of all parameters were larger in Yannong 19 than in Yangmai 16. The high Tr value and slow reduction of Rubisco amount in Yangmai 16 are probably crucial reasons for its high photosynthetic rate.
出处
《作物学报》
CAS
CSCD
北大核心
2009年第8期1500-1507,共8页
Acta Agronomica Sinica
基金
中国科学院南京土壤研究所知识创新工程领域前沿项目(ISSASIP0709)
国家自然科学基金项目(30770408)
中国科学院国际合作重点项目(GJHZ05)
日本环境厅全球环境研究基金项目资助
