Response Characteristics of Photosynthetic Rate to Light Intensity and CO_2 Concentration of Grape

In order to study the management and water-saving irrigation technology for Turpan Grape,photosynthesis of grape was determined in Turpan area with CIRAS-3portable photosynthesis system.The results showed that when the photosynthetically active radiation in the range of 0~600μmol·m-2·s-1,the net photosynthetic rate increased rapidly;in 600~1 500μmol·m-2·s-1 the net photosynthetic rate;and in 1 500~2 000μmol·m-2·s-1,the net photosynthetic rate increased with the photosynthetically active radiation decreased.The concentration of CO2 before 800μmol·m-2·s-1,the photosynthetic rate increased rapidly;after800μmol·m-2·s-1,the photosynthetic rate increased slowly.Light response curve and CO2 response curve were fitted with the nonrectangular hyperbola model and the rectangular hyperbola model,the determination coefficient were 0.996 2and 0.988 5.