摘要
为探明北方荒漠地区重要治沙造林先锋树柠条锦鸡儿对高温胁迫的光合生理适应机制,通过测定柠条锦鸡儿在25℃和36℃温度处理的光合参数和叶绿素荧光特性,研究其对高温胁迫的响应和适应机制。结果表明:高温胁迫下,柠条锦鸡儿的光合速率(Pn)、气孔导度(Gs)和水分利用效率(WUE)显著降低,蒸腾速率(Tr)提高。胞内CO2浓度(Ci)和气孔限制值(Ls)对高温胁迫的响应与光合有效辐射(PAR)相关,当PAR>200μmol/(m2·s)时,Ci下降,Ls上升;当PAR<200μmol/(m2·s),Ci上升,Ls下降。高温胁迫导致柠条锦鸡儿的光能热耗散量(1-Fv′/Fm′)显著提高,但对电子传递速率(ETR)、实际光化学效率(ΦPSⅡ)和光化学淬灭系数(qP)的影响不显著。36℃高温胁迫限制了柠条锦鸡儿的光合作用,但对光系统Ⅱ的功能没有明显影响;气孔限制是造成光合作用下降的主要因素,同时柠条锦鸡儿通过提高蒸腾速率降低叶片温度和增强过剩光能的热耗散以适应高温环境。
In order to explore the photosynthetic adaption mechanisms of C.korshinskii to high temperature stress,photosynthetic parameters and chlorophyll fluorescence characteristics were measured at 25℃ and 36℃.Results:High temperature stress strongly reduced net photosynthetic rate,stomatal conductance and water use efficiency of C.korshinskii,while resulted in an increase in transpiration rate.Responses of intercellular CO2(Ci)and Lsto high temperature stress were closely related to the PAR.When PAR〉200μmol/(m2·s),Ciincreased and Lsdecreased with high temperature;when PAR〈200μmol/(m2·s),Cidecreased and Lsincreased with high temperature.High temperature had no significant effect on ETR,ΦPSⅡand qP,but strongly increased 1-Fv′/Fm′in C.korshinskii.Overall,these results suggested that the temperature at 36℃limited photosynthesis of C.korshinskii which was mainly caused by stomatal limitation,but had no effect on the function of PSⅡ,and furthermore,this species could improve transpiration rate to lower leaf surface temperature and could dissipate excessive light energy by thermal dissipation to adapt high temperature conditions.
出处
《贵州农业科学》
CAS
2015年第9期38-41,共4页
Guizhou Agricultural Sciences
基金
国家自然科学基金项目"锦鸡儿属三个替代近缘种对环境变化的生理生态特征比较"(31260166)
关键词
高温胁迫
柠条锦鸡儿
光合参数
叶绿素荧光
high temperature
Caragana korshinskii
photosynthetic parameter
chlorophyll fluores-cence