珠子参不同居群的光合特性及保护酶活性比较

测定了相同栽培条件下珠子参不同居群的光合特性、保护酶活性、丙二醛含量和叶绿素含量,以探讨其生理生态适应性机理.结果表明,8个珠子参居群的生理生态适应性存在一定差异,居群7、1的净光合速率(Pn)分别是居群4的2.21倍和2.18倍、居群6的2.02倍和2.00倍,差异显著.居群7、1的气孔导度(Cond)和蒸腾速率(Tr)最大,其中居群1的Cond和Tr值分别是居群6的2.61倍和2.35倍,差异显著,蒸汽压亏缺值较小;而居群4、6情况相反.表明珠子参居群植株利用水分的能力存在差异,可能是导致它们之间光合能力存在差异的主要原因之一.居群4、6的超氧化物歧化酶活性较大,过氧化氢酶和过氧化物酶活性显著小于居群7、1,丙二醛含量最大,Pn值最小.表明珠子参不同居群的抗氧化酶系统之间存在一定的协同关系,该协同作用与光合作用密切相关,可能是珠子参适应环境变化的重要生理机制之一.

Comparative study on photosynthetic characteristics and protective enzyme activities in different populations of Panax japonicus C.A.Meyer var major (Burk.) C.Y.Wu et K.M.Feng

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.