Primary Studies On The Super Hybrid Rice Photosynthesis Characteristic

The super hybrid rice photosynthesis characteristic was studied with two years of the pot experiment , field plot experiment and the laboratory analysis. The photosynthetic characteristics were compared between II you ming86, Liangyou peijiu, P88S/0293—three super hybrid rice combinations and Shanyou 63—3-lines hybrid rice combination, Xiangzhou 8—traditional rice cultivar. The main conclusions are as follows:1. Compared between two analysis methods of the photosynthetic light-response curve data, the Non-rectangular Hyperbola model was found to be more objective to calculate the photosynthetic parameters and simulate the photosynthetic light-response curve when the data were processed by the nonlinear statistical regression function of SPSS software and combined with linear regression in the low light period. Binomial regression curve could simulate photosynthetic light-response curve data, but it could not calculate apparent quantum yield( Φ) and explain that net photosynthesis rates (Pn) predicted declines quickly when photosynthetic photo flux density (PPFD) excesses the light-saturation point.2. The different rice cultivar (combinations) on photosynthetic gas exchange and physiologic features in the flag leaves were studies and compared, such as net photosynthesis rate(Pn), Stomatal conductance to H₂O (Cond), CO₂ concentration at Intercellular spaces (Ci), Transpiration rate (Tromml) and water use efficency(WUE) et al. In early development stage(seedling stage , tillering stage )of different rice cultivar (combinations), the photosynthetic characters of the 5 rice cultivar (combinations) was not significant. After heading stage, the main photosynthetic parameters of super hybrid rice combinations were higer than that of CK, especially under the saturation light conditions of tillering and heading stages. The results of the Q-cluster analysis showed that at seeding and tillering stages the photosynthetic characters of the super hybrid rice combinations (II you ming86, Liangyou peijiu, P88S/0293) and Shanyou 63, Xiangzhou 8 was not significant, but after tillering stage the predominance of the super hybrid combinations began to be clear, especial II you ming86 . The water use efficiency of the super hybrid rice combinations were slightly higher than that of Shanyou 63, but was lower from tillering to heading stages. The light saturation point(LSP) of Liangyoupeijiu, P88S/0293 was 850. 217 μmol CO₂. m-2.s-1 and 605.074 μmol CO₂. m-2.s-1, while LSP of Shanyou 63 and Xiangzhou 8 only 547. 636 μmol CO₂. m^-2.s-1, 480. 935 μmol CO₂. m-2-s-1; it indicated that the super hybrid rice combinations could carry out photosynthesis at strong light condition. The light compensation point(LCP) of 5 rice cultivars (combinations) was 89.026μmol CO₂. m-2s-1(II you ming86), 58. 444 μmol CO₂. m-2s-1 (Liangyou peijiu), 44.364 μmol CO2- m-2s-1(P88s/0293), 39. 970μmol CO2 m-2.s-1(Shanyou 63)and 28.953 CO₂. m-2.s-1(Xiangzhou 8).The Apparent Quantum Yield(AQY) of 5 rice cultivars (combinations) was 0.075(II you ming86), 0.046(Liangyou peijiu), 0.035(P88s/0293),...