Figure legends
Fig 1. Air temperature and photosynthetic photon flux density (PPFD) at each observation time during jointing, heading and grain filling stages.
Fig. 2 Diurnal variation of maximum photochemical efficiency of PSII (Fv/Fm) under different treatments of CO2 concentration [CO2] elevation. (a) and (d) were measured at jointing stage, (b) and (e) at heading stage, and (c) and (d) at grain filling stage. AI+160and AI+200 and were short-term (one growing season) abrupt increase of [CO2] by ~160 μmol mol-1 and ~200 μmol mol-1, respectively. CI: constant increase of [CO2] by ~200 μmol mol-1 based on ambient [CO2] for four generations. SI: stepwise increase of [CO2] for four generations with the [CO2] being ~40, 80, 120 and 160 μmol mol-1 higher than ambient in each generation. Data is mean ± SE (n=12). Significance levels of Fv/Fm between two treatments at the same time points are indicated by +, * and ** forp <0.1, p <0.05 andp <0.01.
Fig. 3 Correlation between maximum photochemical efficiency of PSII (Fv/Fm) and photosynthetic photon flux density (PPFD) and air temperature (n=32) at jointing (a, d), heading (b, e) and grain filling stage (c, f). AI+160 and AI+200 were short-term (one growing season) abrupt increase of [CO2] by ~160 μmol mol-1 and ~200 μmol mol-1, respectively. CI: constant increase of [CO2] by ~200 μmol mol-1 based on ambient [CO2] for four generations. SI: stepwise increase of [CO2] for four generations with the [CO2] being ~40, 80, 120 and 160 μmol mol-1 higher than ambient in each generation. Values are probability levels for significant differences.
Fig.4Diurnal variation of efficiency that trapped exciton moves an electron further than QA- in rice under different treatment of CO2 concentration [CO2] elevation. (a) and (d) were measured at jointing stage, (b) and (e) were measured at heading stage, and (c) and (d) were observed at grain filling stage. AI+160 and AI+200 were short-term (one growing season) abrupt increase of [CO2] by ~160 μmol mol-1 and ~200 μmol mol-1, respectively. CI: constant increase of [CO2] by ~200 μmol mol-1 based on ambient [CO2] for four generations. SI: stepwise increase of [CO2] for four generations with the [CO2] being ~40, 80, 120 and 160 μmol mol-1 higher than ambient in each generation. Data is mean ± SE (n=12). Significance levels of ψo between two models at the same time are indicated by +, * and ** for p <0.1,p <0.05 and p <0.01.
Fig. 5 Diurnal variation of electron transport quantum yield (φEo) in rice under different treatment of CO2 concentration [CO2] elevation. (a) and (d) were measured at jointing stage, (b) and (e) were measured at heading stage, and (c) and (d) were observed at grain-filling stage. AI+160 and AI+200 were short-term (one growing season) abrupt increase of [CO2] by ~160 μmol mol-1 and ~200 μmol mol-1, respectively. CI: constant increase of [CO2] by ~200 μmol mol-1 based on ambient [CO2] for four generations. SI: stepwise increase of [CO2] for four generations with the [CO2] being ~40, 80, 120 and 160 μmol mol-1 higher than ambient in each generation. Data is mean ± SE (n=12). Significance levels of φEo between two models at the same time are indicated by +, * and ** for p <0.1,p <0.05 and p <0.01.
Fig. 6 Diurnal variation of performance index (PIABS) in rice under different treatment of CO2 concentration [CO2] elevation. (a) and (d) were measured at jointing stage, (b) and (e) were measured at heading stage, and (c) and (d) were observed at grain-filling stage. AI+160 and AI+200were short-term (one growing season) abrupt increase of [CO2] by ~160 μmol mol-1 and ~200 μmol mol-1, respectively. CI: constant increase of [CO2] by ~200 μmol mol-1 based on ambient [CO2] for four generations. SI: stepwise increase of [CO2] for four generations with the [CO2] being ~40, 80, 120 and 160 μmol mol-1 higher than ambient in each generation. Data is mean ± SE (n=12). Significance levels of PIABS between two models at the same time are indicated by +, * and ** for p <0.1,p <0.05 and p <0.01.