Abstract:Objective The effects of various fungicides combination on photosynthetic characteristics of Panax ginseng were studied.Methods The diurnal variation of photosynthetic rate,the light response curve,and the CO2 response curve of the ascending and oblique ginseng leaf blades with new fungicides combination application,spotted flat ginseng leaf blades with routine fungicides combination application, and flat leaf blades without drug spot after cleaning were measured by using the CI-340 photosynthetic de- termination system.Results The results showed that the diurnal variation of the net photosynthetic rate was two-peak curve on five-year-old P.ginseng leaf blades.The first peak occurred at 10:00 a.m.,the second at 15:00 p.m.The light compensation points(LCP)of ascending and oblique leaf blades,flat leaf blades without drug spot,and the spotted flat leaf blades were 11.5,21.7,and 41.7μmol/(m2·s),re- spectively.The light saturation points(LSP)were 1 008,961,and 954 mol/(m2·s),respectively.The CO2 compensation points(CCP)were 239,240,and 300μmol/mol,respectively.The CO2 saturation points(CSP)were 1 260,1 289,and 1 300μmol/mol,respectively.Conclusion The ascending and oblique leaf blades are higher than the others in the daily outcome of photosynthesis and more adaptable to light and CO2 environment,the drug spot on leaf blades of P.ginseng has the negative effects on photo- synthesis.