Abstract: Two-year-old “chunjie” peach tree as materials , the changes of the characteristics of photosynthesis and chlorophyll fluorescence were investigated through shading in protected culture. The result showed: the light compensation point(LCP)、light saturation point(LSP)、CO2 saturation point(CSP)、CO2 compensation point(CCP)、Rubisco activity 、apparent quantum yield (AQY)、photoresperition、Glycolic acid oxidase activity and carboxylation efficiency(CE) reduced with the reduction of photo flux intensity; but the content of chlorophyll and carotenoid increased under low light environment. The diurnal changes of φPSⅡ、Fo and Fv/Fm were different apparently, and the diurnal changes of φPSⅡ and Fv/Fm of the two low light trentments were stable and had high values, but the full sunlight treatment changed sharply; the diurnal changes of Fo values of three treatments were similar.

Key words: Photon Flux Density, Protected culture, Peach tree, Photosynthetic characteristics, Chlorophyll fluorescence