中文摘要：

在六稀罕、危及的种类 Neolitsea sericea 的叶子的煤气的交换和叶绿素荧光的参数， Cinnamomum japonicum var。chenii， Sinojackia microcarpa， Discocleidion glabrum var。trichocarpum， Parrotia sub-aequalis， Cercidiphyllum japonicum 在领域里被测量。结果证明在光合的能力有重要差别，内在的水使用效率( WUE )， PS II 和它的潜在的活动的光能的主要变换的效率， PS II 的量收益电子运输，并且在六种之中的热驱散的潜在的能力。结果显示了那 D。glabrum var。trichocarpum 有更高光合的能力和更差的 WUE，当时 S。microcarpa 有更低的光合的能力和更大的 WUE。而且，平均数最大的荧光珍视， PS II (Fv/Fm ) 的光能的主要变换的潜在的效率， PS II， PS II (Fv/Fm ) 和非光化学的熄灭系数的光能的主要变换的实际效率在 S 是最高的。microcarpa。

英文摘要：

The parameters of gas exchange and chlorophyl fluorescence in leaves of six rare and endangered species Neolitsea sericea, Cinnamomum japonicum var. cheni , Sinojackia microcarpa, Discocleidion glabrum var. trichocarpum, Parrotia sub-aequalis, Cercidiphyl um japonicum were measured in fields. The results showed that there were significant differences in photosynthetic capacity, intrinsic water use effi-ciency （WUEi ）, the efficiency of primary conversion of light energy of PSⅡ and its potential activity, the quantum yield of PSⅡ electron transport, and the potential ca-pacity of heat dissipation among the six species. However, there was no significant difference in WUE. The highest values of net photosynthetic rate （Pn）, transpiration rate （Tr） and stomatal conductance （gs） occurred in D. glabrum var. trichocarpum and the lowest in S. microcarpa. On the contrary, D. glabrum var. trichocarpum had the lowest WUE, intrinsic water use efficiency （WUEi ） and S. microcarpa had the highest. The results indicated that D. glabrum var. trichocarpum had higher photo-synthetic capacity and poorer WUE, while S. microcarpa had lower photosynthetic capacity and greater WUE. Furthermore, the mean values of maximal fluorescence （Fm）, potential efficiency of primary conversion of light energy of PSⅡ （Fv/Fm）,ΦPSⅡ, actual efficiency of primary conversion of light energy of PSⅡ （F′v/F′m） and non-photochemical quenching coefficient （NPQ） were the highest in S. micro-carpa, indicating that its PSⅡ had higher capacity of heat dissipation and could prevent photosynthetic apparatus from damage by excessive light energy. Correlation analysis showed that there were significant correlations among photosynthetic physi-ological parameters. However, the initial fluorescence （Fo） was not significantly cor-related with any other parameters. This study also revealed the extremely significant positive correlations between Pn and Tr, gs, apparent quantum yield （AQY）, be-tween Tr and gs, be