中文摘要：

在同一生长环境下,测定两种分布在不同海拔的圆柏属植物叶绿素荧光参数的季节变化,探讨二者光合特征的季节变化模式和差异,研究结果表明,祁连圆柏（Sabina przewalskii Kom.）和圆柏（Sabina chinensis（Lin.）Ant.）的最大光化学效率（Fv/Fm）、有效光合效率（F′v/F′m）、光化学淬灭系数（qP）、非光化学淬灭系数（qN）、电子传递速率（ETR）和有效量子产量（Yield）有相似的季节变化模式,均表现为冬季低,夏季高。两种测试植物叶绿素荧光参数之间差异显著（p〈0.05）,祁连圆柏叶片的Fv/Fm、F′v/F′m、qP、qN、ETR和Yield均显著高于圆柏。可见分布在较高海拔的祁连圆柏的光合潜能高于低海拔的圆柏,祁连圆柏应对低温诱导有更广泛的调节能力,同时证实叶绿素荧光技术可作为衡量抗寒性强弱和叶片光合特性季节变化的有效手段。

英文摘要：

Chlorophyll fluorescence parameters of Sabina przewalskii Kom. and Sabina chinensis（Lin.） Ant. that distributed in different altitude regions were tested for evaluating their differences and seasonal variation patterns at the same growing circumstance. The results indicated, there were similar patterns of seasonal variation in chlorophyll fluorescence parameters between two Sabina trees, the low temperature in winter resulted in a significant decreases in the maximum efficiency of PSⅡ photochemistry （Fv/Fm）, the efficiency of excitation capture by open reaction centers （F′v/F′m）, photochemical quenching coefficient（qP）, non-photochemical quenching coefficient （qN）, effective quantum yield（Yield） and photosynthetically active radiation（PAR） in both S.przewalskii and S.chinensis, however, these parameters all increased and returned to normal levels as air temperature rose. Compared with those in S.chinensis, there were significantly higher Fv/Fm, F′v/F′m, qP, qN and Yield in S.przewalskii. These results suggested a better capacity for PSⅡ photochemistry in S.przewalskii. might account for its greater regulation capacity for low temperature than S.chinensis, and at the same time it implied that the cold-resistance ability and seasonal variation of photosynthetic characteristics can effectively be estimated by chlorophyll fluorescence technology.