To examine the effects of elevated CO2 concentrations on chlorophyll fluorescence of rice leaf, a field experiment was conducted with automatic control system of CO2 concentration in open top-chambers (OTCs). There were three treatments, including atmospheric CO2 concentration (CK), CK+80 μmol·mol-1 CO2 (T1), and CK+200 μmol·mol-1 CO2 (T2). The fast chlorophyll fluorescence induction dynamic curves of flag leaves were measured using the plant efficiency analyzer at the main growth stages of rice. The results showed that T1 treatment significantly increased quantum yield for electron transfer (φEo), maximum photochemical efficiency (Fv/Fm), and performance index (PIABS), but decreased quantum yield for energy dissipation (φDo) at the flowe-ring, milk grain, ripening, and full ripeness stages. The values of φEo, Fv/Fm, and PIABS were increased by 7.3%-23.3%, 3.1%-7.1%, and 46.2%-93.0%, respectively. The φDo values were decreased by 10.3%-20.5%. T2 treatment significantly decreased φEo, Fv/Fm, PIABS by 68.7%, 41.4%, and 93.4%, respectively, but increased φDo by 78.4% at the jointing stage. T2 treatment significantly increased φEo, Fv/Fm, PIABS by 11.6%-19.8%, 4.8%-6.8%, and 53.0%-72.6%, respectively, and decreased φDo by 7.7%-19.4% at the flowering, milk grain, and ripening stages. Our results suggested that elevated CO2 concentration (80, 200 μmol·mol-1) would promote photosynthetic electron transport of PS2 in flag leaves of rice.
为研究不同CO2浓度升高水平对水稻叶片荧光特性的影响,利用开顶式气室组成CO2浓度自动调控平台开展田间试验,使用便携式植物效率分析仪测定剑叶快速叶绿素荧光诱导动力学曲线,分析不同CO2浓度(CK:背景大气CO2浓度;T1:比CK的CO2浓度高80 μmol·mol-1;T2:比CK的CO2浓度高200 μmol·mol-1)下水稻主要生育期剑叶快速叶绿素荧光诱导动力学参数的变化特征.结果表明:CO2浓度升高80 μmol·mol-1,用于电子传递的量子产额(φEo)、最大光化学效率(Fv/Fm)、性能指数(PIABS)在扬花期、乳熟期、蜡熟期和完熟期均显著升高,用于热耗散的量子比率(φDo)显著降低,其中φEo显著升高了7.3%～23.3%,Fv/Fm极显著升高了3.1%～7.1%,PIABS极显著升高了46.2%～93.0%,φDo则显著降低了10.3%～20.5%.CO2浓度升高200 μmol·mol-1,在拔节期,φEo、Fv/Fm、PIABS分别极显著降低了68.7%、41.4%和93.4%,φDo则极显著升高了78.4%;在扬花期、乳熟期、蜡熟期,T2使φEo显著升高了11.6%～19.8%,Fv/Fm显著升高了4.8%～6.8%,PIABS显著升高了53.0%～72.6%,φDo则显著降低了7.7%～19.4%.表明CO2浓度升高(80、200 μmol·mol-1)对水稻剑叶光系统Ⅱ的光合电子传递具有促进作用.
Keywords: CO 2 concentration; Japonica rice; PS2; chlorophyll fluorescence.