水稻叶绿素荧光特性对CO_2浓度升高的代际响应研究

Intergenerational Response of Chlorophyll Fluorescence Characteristics of Rice to Elevated CO_2 Concentration

为研究不同CO_2浓度升高水平对水稻叶绿素荧光特性的代际影响,基于CO_2浓度自动调控系统开展田间试验,以上一生长季经CO_2浓度升高处理(CO_2浓度比自然环境高40μmol·mol^(-1))的粳稻(Oryza sativa L.)种子(SI)和没有经过CO_2浓度升高处理的粳稻种子(SII)为试验材料,设置3种CO_2浓度水平:以背景大气CO_2浓度为对照(CK)、CO_2浓度比CK分别增加80μmol·mol^(-1)(T_1)和200μmol·mol^(-1)(T_2),测定叶片叶绿素荧光参数。结果表明,与CK相比,T_1处理使SI和SII蜡熟期的基础荧光(F_o)分别下降了8.6%(P=0.004)和8.0%(P=0.033),T_2处理使SI和SII扬花期的F_o分别下降了12.5%(P=0.033)和18.0%(P=0.015)。T_1处理使SI和SII蜡熟期的最大荧光(F_m)分别上升了10.1%(P=0.001)和11.0%(P=0.001),T_2处理使F_m分别上升了12.0%(P=0.000)和10.6%(P=0.001)。T_1处理使SI和SII蜡熟期的可变荧光(F_v)分别上升了16.2%(P=0.001)和17.7%(P=0.001),T_2处理使F_v分别上升了18.2%(P=0.000)和17.6%(P=0.000)。T_1处理使SI和SII蜡熟期的最大光化学效率(F_v/F_m)分别上升了6.2%(P=0.001)和6.5%(P=0.005),T_2处理使F_v/F_m分别上升了6.2%(P=0.001)和6.8%(P=0.003)。与CK相比,T_1和T_2处理使SI和SII的单位反应中心吸收的光能(ABS/RC)、单位反应中心捕获用于还原QA的能量(TRo/RC)、单位反应中心以热能形式耗散的能量(DIo/RC)在乳熟期、蜡熟期和完熟期下降,单位面积光合反应中心的数量(RC/CSo)在蜡熟期上升。SI与SII相比,它们的F_o、F_m、F_v、F_v/F_m、ABS/RC、TRo/RC、DIo/RC、RC/CSo、ETo/RC没有显著差异。研究表明CO_2浓度升高有利于提高水稻叶片光合系统的光能转换能力,对光合功能有促进作用,而叶绿素荧光特性对CO_2浓度升高的响应没有代际差异。

To study the intergenerational influence of different levels of elevated CO2 concentration on chlorophyll fluorescence characteristics of rice, a field experiment was carried out based on the automatic control system of CO2 concentration in farmland.Here, the seeds from japonica rice(Oryza sativa L.) that treated with elevated CO2 concentration(SI)(which was 40 μmol·mol^-1 higher than that of the natural environment) and without elevated CO2 concentration(SII) during the last rice growing season were used. The experimental treatments included the ambient CO2 concentration(CK), 40 μmol·mol^-1 above CK(T1), and 200μmol·mol^-1 above CK(T2). Rice chlorophyll fluorescence parameters were determined. The results showed that compared with CK,T1 treatment significantly decreased the basic fluorescence(Fo) of SI and SII by 8.6%(P=0.004) and 8.0%(P=0.033), respectively,in the ripening stage. T2 treatment significantly decreased Fo of SI and SII by 12.5%(P=0.033) and 18.0%(P=0.015), respectively,during the flowering stage. T1 treatment significantly increased the maximum fluorescence(Fm) of SI and SII by 10.1%(P=0.000)and 11.0%(P=0.005), respectively, in the ripening stage. T2 treatment increased Fm of SI and SII by 12.0%(P=0.000) and 10.6%(P=0.001), respectively. T1 treatment significantly increased the variable fluorescence(Fv) of SI and SII by 16.2%(P=0.001) and17.7%(P=0.001), respectively, during the ripening stage. T2 treatment also increased Fv of SI and SII by 18.2%(P=0.000) and 17.6%(P=0.000), respectively. T1 treatment significantly increased the maximum photochemical efficiency(Fv/Fm) of SI and SII by 6.2%(P=0.001) and 6.5%(P=0.005), respectively, during the ripening stage, and T2 treatment also increased Fv/Fm of SI and SII by 6.2%(P=0.001) and 6.8%(P=0.003), respectively. Compared with CK, both T1 and T2 treatments decreased the light energy absorbed by unit reaction centers(ABS/RC), the energy captured by unit reaction centers for QA reduction(TRo/RC), and the energy dissipated by unit reaction centers in the form of thermal energy(DIo/RC) of SI and SII rice during the milk ripening, wax ripening, and ripening stages, but increased the number of photosynthetic reaction centers per unit area(RC/CSo) during the wax ripening stage. There were not significant differences between SI and SII rice in Fo, Fm, Fv, Fv/Fm, ABS/RC, TRo/RC, DIo/RC, RC/CSo, and ETo/RC. The results of this study suggest that elevated CO2 concentration should be beneficial to improve the ability of light energy conversion in the photosynthetic system of rice leaf, and promote the photosynthetic function, but there is no generational difference in the response of chlorophyll fluorescence characteristics to elevated CO2 concentration.