开放式臭氧浓度升高对水稻叶片气体交换和荧光特性的影响

Effects of O_3-FACE(Ozone-Free Air Control Enrichment) on Gas Exchange and Chlorophyll Fluorescence of Rice Leaf

利用稻/麦O3-FACE(Ozone-free air controlled enrichment)平台,以武运粳21和两优培九两个耐性不同的水稻品种为材料,模拟研究了近地层大气臭氧浓度升高情形下对水稻叶片气体交换和荧光参数的影响。结果表明:高臭氧浓度降低了两个品种水稻叶片的净光合速率、气孔导度以及蒸腾速率,处理76天后,武运粳21的降幅分别为:21.7%,26.64%和24.74%,两优培九的降幅分别为:25.53%,30.31%和25.48%,而对两个品种胞间CO2浓度的影响不显著;水稻叶片荧光动力学参数F0(暗下初始荧光)、ETR(表观电子传递速率)和ФPSⅡ(PSⅡ实际光化学量子产量)呈下降趋势,NPQ(非光化学猝灭系数)逐渐上升,处理76天后武运粳21和两优培九分别上升了16.37%和11.77%。臭氧的影响有一定的累积效应,随着处理时间的延长,相关指标变化幅度增大。高臭氧浓度下水稻叶片胞间CO2浓度没有显著降低,推断臭氧导致的净光合速率的降低是由非气孔限制因素引起。结果表明,两优培九比武运粳21对臭氧响应敏感。

O3-FACE （Ozone-free air control enrichment） platform has been established for observing the effect of elevated tropospheric ozone concentration on the gas exchange and chlorophyll fluorescence of two rice varieties （Wuyunjing 21 and Liangyoupeijiu）. The results showed that high ozone concentration decreased the net photosynthetic rate （Pn）, stomatal conductance （Gs）, and transpiration rate （Tr） of rice leaves. After 76d fumigation the decline in them for Wuyunjing 21 was as follows： 21.7%, 26. 64% and 24. 74% respectively, and that for Liangyoupeijiu was as follows： 25.53%, 30. 31% and 25.48% respectively; however, no significant impact on leaf intercellular CO2 concentration was observed. Chlorophyll fluorescence kinetics parameters changed as can be seen by the decrease in F0 （initial fluorescence in the dark）, ETR （The apparent electron transfer rate） and ФPSⅡ （actual photochemical efficiency of PSⅡ in the light）, and the increase in NPQ （non-photochemical quenching）. After 76 days of O3 treatment,the NPQ of Wuyunjing 21 and Liangyoupeijiu was enhanced by 16. 37% and 11.77%, respectively. The impact of ozone on rice was a cumulative effect, and the extent of variation in the above parameters and the differences between the two varieties were enlarged as the O3 treatment time increased; At the same time because the rice leaf intercellular CO2 concentration did not significantly reduce, the inferred decrease in net photosynthetic rate was restricted by non-stomatal factors. The results of this experiment indicated that Liangyoupeijiu was more susceptible to ozone than Wuyunjing 21.