矮生杉木光合特性及叶绿素荧光参数研究

Photosynthetic properties and chlorophyll florescence parameters of dwarf Chinese fir.

为揭示杉木矮生的原因,以矮生杉木、正常杉木为材料,对其光合特性和叶绿素荧光参数进行了比较研究。结果表明:矮生型叶片的光补偿点和光饱和点分别为18.44和500μmol/(m2.s),正常型叶片相应值分别为7.32和1 500μmol/(m2.s),表明矮生型的光能利用能力明显不如正常型;在光合参数方面,矮生型叶片的净光合速率(Pn)、气孔导度(Gs)及蒸腾速率(Tr)均低于正常型,但两者胞间二氧化碳浓度(Ci)差异不大,表明矮生型较低的净光合速率可能是非气孔限制的结果;对于叶绿素荧光参数,矮生型经充分暗驯化后的初始荧光(F0)、最大荧光(Fm)、PSⅡ内禀光能转换效率(Fv/Fm)及PSⅡ潜在活性(Fv/F0)几乎均小于正常型。因此,矮生杉木光合能力上的缺陷可能是造成低生长势的重要生理生态原因之一。

To reveal the dwarfing mechanism for the Chinese fir（Cunninghamia lanceolata）,the photosynthetic and chlorophyll fluorescence characteristics of the dwarf and control were comparatively studied.The results showed that light compensation point and light saturation point of the dwarf were 18.44 and 500 μmol/（m^2·s） respectively,and the corresponding values of the control were 7.32 and 1 500 μmol/（m^2·s） respectively,indicating that the dwarf has less ability in using light than control.In the aspect of photosynthetic parameters,the net photosynthetic rate（P_n）,stomatal conductance（G_s） and transpiration rate（T_r） of the dwarf were generally lower than those of control,but there was no obvious differences in inter-cellular CO_2 rates between them.The lower P_n of the dwarf was resulted from non-stomata factors.As to chlorophyll florescence parameters of the dwarf,such as initial chlorophyll fiuorescence（F_0）,maximum chlorophyll fiuorescence（F_m）,optimal photochemical efficiency（F_v/F_m） and potential activity（F_v/F_0） of photosystem II,were generally lower than those of the control.In conclusion,the photosynthetic capacity deficiency of the dwarf is one of the important physiological and ecological reasons for its lower growth potential.