Objective]Caragana genus,a group of shrubs,are used in vegetation restoration and reconstruction in sandy area due to its characteristics of strong tolerance to drought and barren soil. In this study, a repeated low temperature stress experiment was conducted to study the effects of repeated low temperature stresses on chlorophyll fluorescence of four different Caragana species and to analyze the response of the seedlings to the repeated low temperature. [Method]Chlorophyll fluorescence parameters of Caragana. species were measured under room temperature ( daytime:30 ℃,night:20 ℃) ,the first low temperature stress (0 ℃ for 12 h) and the second low temperature stress ( 0 ℃ for 24 hours) . The influence of the repeated low temperature stress on the chlorophyll fluorescence parameters were analyzed in four different Caragana species. [Result]Initial fluorescence ( Fo ) of different Caragana species had an increase tendency under the repeated low temperature stress,but maximum fluorescence ( Fm ) ,maximum photochemical efficiency of PSⅡ (Fv/Fm),PSⅡ electron transfer rate (ETR) and PSⅡ photochemical fluorescence quenching coefficient ( qP ) showed a decreasing tendency. After repeated low temperature stress,initial fluorescence of C. tibetica increased significantly ( P >0 . 05 ) ,and maximum fluorescence and maximum photochemical efficiency of PSⅡ of four different Caragana species decreased significantly (P<0. 05). The PSⅡ electron transfer rate of C. microphylla and C. tibetica was decreased significantly (P<0. 05). The PSⅡ photochemical fluorescence quenching coefficient of C. korshinskii,C. tibetica and C. microphylla was decreased significantly ( P < 0. 05 ). The PSⅡ non - photochemical fluorescence quenching coefficient (NPQ) of C. korshinskii was increased significantly (P<0. 05),but C. microphylla was decreased significantly ( P <0 . 05 ) . [Conclusion]The result indicated that the repeated low temperature stress influenced the photosynthetic apparatus of different Caragana species, and photosynthetic capacity of different Caragana species decreased under the repeated low temperature stress. C. intermedia,C. korshinskii and C. tibetica showed an ability of consuming the surplus excitation energy to protect photosynthetic apparatus under the repeated low temperature stress. All the analysis shows that C. intermedia and C. korshinskii have a strong adaptability to the repeated low temperature stress than C. microphylla and C. tibetica.%【目的】通过研究4种锦鸡儿对重复低温胁迫的响应机制，探讨重复低温胁迫对4种锦鸡儿幼苗光合特性的影响，分析4种锦鸡儿对重复低温胁迫的响应机制，筛选耐寒性极强的锦鸡儿植物，为高寒沙区植被恢复提供科学依据。【方法】以盆栽的4种锦鸡儿为材料，分别测定不同锦鸡儿在室温(白天：30℃，夜间：20℃)、第1次低温(0℃胁迫12 h)和第2次低温(0℃胁迫24 h)后的叶绿素荧光参数，分析重复低温胁迫对4种锦鸡儿叶绿素荧光参数的影响。【结果】在重复低温胁迫后，不同锦鸡儿初始荧光(Fo)呈现增加的趋势，最大荧光(Fm)、最大光化学效率( Fv/Fm )、PSⅡ电子传递速率( ETR)和光化学猝灭系数( qP )呈现降低的趋势。川青锦鸡儿的 Fo显著增加(P＜0.05)；4种锦鸡儿的 Fm和 Fv/Fm均显著降低(P ＜0.05)；小叶锦鸡儿和川青锦鸡儿的 ETR 显著降低(P ＜0.05)；柠条锦鸡儿、川青锦鸡儿和小叶锦鸡儿的 qP显著降低(P＜0.05)；柠条锦鸡儿的非光化学猝灭系数(NPQ)显著增加(P＜0.05)，小叶锦鸡儿的 NPQ显著降低(P＜0.05)。【结论】重复低温胁迫对4种锦鸡儿幼苗叶片的光合机构均产生不同程度影响，在低温胁迫过程中，中间锦鸡儿、柠条锦鸡儿和川青锦鸡通过增加热耗散以消耗过剩的激发能，减少低温胁迫对光合机构损害的能力。综合分析表明，中间锦鸡儿和柠条锦鸡儿对重复低温胁迫具有较强的适应性，小叶锦鸡儿和川青锦鸡儿对重复低温胁迫的适应性稍差。
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