Effects Of Open Temperature Increasing On Photosynthetic Characteristics And Yield Of Japonica Rice In North Of China

The study used Shennong 9816,Liaojing 401,Tiejing 7 and Gangfujing 16 as materials,using FATI system,taking ambient temperature as control,and measured the photosynthetic parameters,chlorophyll fluorescence parameters,antioxidant enzymes,rice yield and quality.To analyze the response differences of activity and productivity of different varieties of rice photosynthesis system,and the method provided a reference for the effects of global warming on rice production.The results showed that:1.The effect on photosynthetic parameters: The warming treatment significantly reduced the SPAD value of the flag leaf of Shennong 9816 and Liaojing 401,and had no effect on the SPAD value of the Tiejing 7 and Gangfujing 16.Pn and Gs of the flag leaf of Shennong 9816 and Liaojing401 decreased significantly on the 0 to 30 days after heading.Pn in the flag leaf of Gangfujing 16 decreased significantly on the 20 th day after the heading.Liaojing 401 on the 30 th day and Gangfujing 16 on the 20 th day Ci and Tr were significantly reduced.2.The effect on chlorophyll fluorescence parameters: After warming treatment,Shennong 9816 on the 10 to 20 days,Liaojing 401 and Gangfujing 16 on the 0 to 10 days after heading,Wk and Vj significantly increased.The reaction center performance index PIabs,PItot and reaction center density RC/CSo were significantly reduced.The specific activity parameters ABS/CSm,TRo/CSm,ETo/CSm,REo/CSm per unit area were significantly reduced with the heat dissipation per unit area of the reaction center DIo/CSm increased.And the specific activity parameters of the unit reaction center ABS/RC,TRo/RC,ETo/RC,REo/RC were increased.PI abs and PI tot of Shennong 9816,Liaojing 401 and Gangfujing 16 increased significantly on the 30 to 40 days after heading.The Fv'/Fm',ETR,?PSII and q P in the flag leaf of Shennong 9816 and Liaojing 401 significantly decreased after 0 to 30 days after heading,and q N increased significantly.The Fv'/Fm',ETR,?PSII and q P in the flag leaf increased significantly after 30 to 40 days after heading,and q N decreased significantly.3.The effect on anti-oxidase activity: After the warming treatment,the contents of MDA and H2O2 in Shennong 9816 and Liaojing 401 were significantly increased,and SOD activity was significantly decreased.The contents of MDA and H2O2 in the flag leaf of Tiejing 7 and Gangfujing 16 had no different or significantly decreased compared with the control,and the SOD activity was significantly increased.4.The effect on yield and quality: The number of grains per panicle,seed setting rate,1000-grain weight and theoretical yield of Shennong 9816 and Liaojing 401 were significantly lower than that of the control,and there was no significant effect on Tiejing 7and Gangfujing 16.The warming treatment did not affect the whole milled rice rate,amylose content and taste value of the tested rice,but significantly increased the whiteness and chalkiness of the tested rice.