臭氧胁迫对水稻光合作用与产量的影响

Influences of Elevated Ozone on Rice Photosynthesis and Yield

采用开顶式气室(OTC),对水稻"3694繁"(Oryza sativa L.3694 Fan)进行田间原位臭氧(O3)熏气实验,研究了不同O3浓度熏气处理下水稻光合色素、气体交换参数以及产量的响应。实验设置分4个水平:过滤大气组(CF,10 nL.L-1)、自然大气组(NF,40nL.L-1)和两个不同浓度的O3处理组(O1:100 nL.L-1;O2:150 nL.L-1)。结果表明:(1)与CF组相比,两个不同浓度的O3处理均导致水稻叶片光合色素含量大幅度下降,加速水稻的衰老过程;(2)在实验进程中,O3处理导致水稻叶片气体交换参数发生显著变化,饱和CO2浓度的净光合速率(Psa)t、气孔导度(Gs)、水分利用效率(WUE)、气孔限制值(Ls)和羧化效率(CE)均呈现下降趋势,表明O3浓度的升高使水稻光合作用对CO2的利用效率降低,水稻在灌浆期对O3最为敏感;(3)O3处理使水稻产量损失明显,当AOT40值达到2.32μL.L-.1h时,就能导致水稻产量10%的减产。

In order to investigate the effects of elevated ozone concentration on the leaf photosynthesis and yield loss of rice （ Oryza sativa L. 3694 Fan）, we planted rice using open-top chambers（OTC ） in situ in Jiaxing, Zhejiang Province and applied four treatments：charcoal-filtered air （CF, 10 nL· L^-1）, unfiltered air （NF, 40 nL· L^-1 ） , and charcoal-filtered air with ozone additions（O1 ： 100 nL· L^-1; O2 ： 150 nL· L^-1）. Rice was exposed to ozone concentrations from July 29 to October 11, 2007 and the actual days of exposure was 54. Photosynthetic pigments, gas exchange parameters and yield of flee were determined. All results indicated that elevated ozone had significant effects on rice photosynthesis and yield loss： （ 1 ）Compared to CF, the content of rice photosynthetic pigments declined markedly under O 1 and O2 treatments and ozone accelerated rice leaf senescence; （2）The gas exchange parameters, including the CO2 saturated rate of photosynthesis （Psat）, stomatal conductance （ Gs ）, water usage efficiency（WUE）, stomal limit value（Ls ） and carboxylation efficiency（CE） significantly decreased, indicating the decrease in CO2 usage efficiency on the photosynthesis of rice under the exposure of elevated ozone concentrations. Rice was the most sensitive to O3 at grain filling stage; （ 3 ）The effects of elevated ozone on the photosynthesis was embodied in the rice yield loss and the rice yield loss reached 10% when AOT40 （Accumulated exposure over athreshold ozone concentration of 40 nL·L^-1） was 2.32 μL· L^-1·h.