毛乌素沙地沙柳光系统Ⅱ光保护机制和能量分配动态及其影响因子  

Light Energy Partitioning,Photoprotection and Influencing Factors of PhotosystemⅡin an Exotic Species(Salix psammophila)in Mu Us Sandy Land

作　　者：靳川 查天山[1] 贾昕[1] 田赟[1] 周文君 卫腾宙 Jin Chuan;Zha Tianshan;Jia Xin;Tian Yun;Zhou Wenjun;Wei Tengzhou(School of Soil and Water Conservation,Beijing Forestry University,Yanchi Research Station Key Laboratory of Soil and Water Conservation of National Forestry and Grassland Administration,Beijing Forestry University,Beijing 100083)

机构地区：[1]北京林业大学水土保持学院/宁夏盐池毛乌素沙地生态系统国家定位观测研究站北京林业大学水土保持国家林业和草原局重点实验室,北京100083

出　　处：《林业科学》2020年第10期34-44,共11页Scientia Silvae Sinicae

基　　金：国家自然科学基金项目(31670708,31670710);中央高校基本科研业务费专项资金(2015ZCQ-SB-02)。

摘　　要：【目的】通过叶绿素荧光原位连续监测技术,探究毛乌素沙地半干旱区典型固沙造林物种沙柳光系统Ⅱ能量分配及其对环境因子的响应,在日和季节尺度下揭示环境因子对沙柳光系统Ⅱ能量分配的动态影响及其光合生理适应策略特征,以期为研究地区的植被恢复管理和物种选择提供理论指导。【方法】在宁夏盐池毛乌素沙地,对固沙物种沙柳进行整个生长季(5—10月)的叶绿素荧光原位连续监测。采用Kramer光能分配方法计算相关荧光参数,采用分段平均方法对数据进行分组平均,利用线性回归在日和季节尺度分析荧光参数与环境因子关系。【结果】在日尺度,实际光化学效率(ΦPSⅡ)和调节性热耗散(ΦNPQ)与光合有效辐射(PAR)直接相关,受空气温度(Ta)、相对湿度(RH)和饱和水汽压差(VPD)的影响,非调节性热耗散(ΦNO)相对稳定。在季节尺度,生长季前期(5—6月)ΦPSⅡ和ΦNPQ分配相对均匀,ΦNO较高且在1天内稳定,最大光化学效率(Fv/Fm)有低值出现。在生长季中期(7—9月),8月ΦPSⅡ降低且伴随ΦNPQ升高,8—9月ΦNO在1天内波动较大。在生长季末期(10月),ΦPSⅡ最低且ΦNPQ达到最高,ΦNO较高且在1天内稳定,Fv/Fm持续降低。【结论】在日尺度,沙柳光系统Ⅱ能量分配主要由PAR和Ta决定,同时受RH和VPD调控。在季节尺度,沙柳光系统Ⅱ能量分配随物候期而变。沙柳Fv/Fm与日最大光合有效辐射(PARmax)(R2=0.13,P<0.01)、Ta变化幅度(R2=0.16,P<0.01)和土壤含水量(SWC)显著相关(R2=0.19,P<0.01),说明高辐射、极端气温和干旱是限制沙柳光系统Ⅱ光合生理状态的主要环境胁迫因子。沙柳光系统Ⅱ能量分配在日与季节尺度的差异,很可能是由于光系统Ⅱ叶黄素循环等短期光保护机制与叶绿素浓度、比值分配等长期调控机制的差异造成。With the technique of in situ continuous monitoring of chlorophyll fluorescence,the energy distribution of photosystemⅡin Salix psammophila and its response to environmental factors were explored in the semi-arid area of Mu Us sandy land.The dynamic effects of environmental factors on energy distribution of the photosystemⅡand their photosynthetic physiological adaptation strategies were revealed in the daily and seasonal scales,in order to provide theoretical guidance for vegetation restoration management and species selection in the study area.【Method】Chlorophyll fluorescence was continuously measured in situ and fluorescence parameters were calculated using Kramer methods of light energy allocation.【Result】At the diurnal scale,photochemical efficiencyΦPSⅡ)and regulated heat dissipationΦNPQ)were directly related to photosynthetically active radiation(PAR),and also influenced by air temperature(Ta),relative humidity(RH)and vapor pressure deficit(VPD).The non-regulate heat dissipationΦNO)was relatively stable.At the seasonal scale,at the early stage of the growing season(May-June),ΦPSⅡandΦNPQ partitioning is relatively uniform,ΦNO was higher and remained stable.Maximum quantum yield of PSⅡphotochemistry(Fv/Fm)declined.In the mid-growing season(July-September),AugustΦPSⅡsignificantly decreased andΦNPQ rose.At the end of the growing season(October),ΦPSⅡwas lowest,ΦNPQ was highest,andΦNO value was higher and more stable.Fv/Fm declined.【Conclusion】On the daily scale,the energy partitioning of photosystemⅡis mainly affected by PAR and Ta,while it is less regulated by RH and VPD.At the seasonal scale,energy partitioning is mainly regulated by the phenological period.Fv/Fm is significantly correlated with PARmax(R2=0.13,P<0.01),Ta variation(R2=0.16,P<0.01)and soil moisture content(SWC)(R2=0.19,P<0.01),indicating that high radiation,extreme temperature and drought are the main environmental stress factors limiting the photosynthetic physiological state of Salix psammophila.Energy pa

关 键 词：半干旱区 沙柳 叶绿素荧光 光系统Ⅱ能量分配 非光化学淬灭 

分 类 号：S718.51[农业科学—林学]