| This paper measured photosynthesis characteristics, protective enzyme activities, membrane peroxidation and chlorophyll content in different populations of Panax japonicus C.A.Meyer var major (Burk.) C.Y.Wu et K.M.Feng under the same cultivation conditions to assess the mechanisms of physiological and ecological adaptability. The results showed that there was different physiological and ecological adaptability in 8 populations. The net photosynthetic rate (Pn) of populations 7 and 1 was 2.21 and 2.18 times to population 4, was 2.02 and 2.00 times to population 6, respectively, and the difference was significant. The highest stomatal conductance (Cond) and transpiration rate (Tr) was in populations 7 and 1, the Cond and Tr of 1 was 2.61 and 2.35 times to population 6, the difference was significant, vapor pressure deficit value was small,but the populations of 4 and 6 were opposite. This showed that the existing differences among populations of P. japonicus.in water use capacity may be one of the main causes of different photosynthetic capacity among different populations. The activities of superoxide dismutase in populations 4 and 6 were higher, but the activities of catalase and peroxidase were significantly lower than those of populations 7 and 1, and populations 4 and 6 had the highest malondialdehyde content and the lowest Pn. The results indicated that there was a synergic relationship in the antioxidase system, which closely associated with photosynthesis, and this may be one of the important physiological mechanisms of P. japonicus var major to adapt to changed circumstances. |
