关键词：
南极假山毛榉;光合作用;叶绿素荧光;温度胁迫
摘 要：
温度对植物的光合作用和地理分布范围均具有重要影响,因此,研究温度变化对南极假山毛榉光合系统的影响,对引种培育具有重要意义.通过人工模拟温度变动(-5、5、15、25、30、35和40℃),对南极假山毛榉1年生苗的叶绿素荧光、快速光响应曲线和叶绿素含量进行了分析.结果表明:1)随着高、低温胁迫的加剧,叶片性能指数(PIABS)、PSⅡ用于光化学反应的能量比例(P)和光能利用效率(α)均呈下降趋势,非光化学猝灭系数(qN)呈持续上升趋势,说明胁迫导致叶片吸收的光能相对过剩;叶绿素荧光动力学曲线出现明显的K点和L点,单位反应中心捕获的用于电子传递的能量(ETo/RC)持续显著下降,说明胁迫主要干扰PSⅡ的放氧复合体和电子传递途径.2)高温40℃胁迫导致非光化学反应耗散能量比例(E)、PSI荧光强度(F1)和PSⅡ单位面积反应中心数量(RC/CS)分别比25℃时增加了110.0%(P <0.01)、178.1%(P <0.01)和6.9%,低温-5℃胁迫导致RC/CS和E分别比25℃时增加了12.8%和43.3%(P <0.01),说明增加叶片荧光散射强度和PSⅡ单位面积反应中心的数量是南极假山毛榉应对高低温胁迫的保护性反应.3)所有测量参数中ETo/RC对温度变化最敏感,非线性拟合显示南极假山毛榉光合作用的最适温度为23.83℃.
作 者：
HAO Xiangchun;ZHOU Shuai;ZHAI Yu;HAN Lijun;Shanxi Academy of Forestry Sciences;
关键词：
Nothofagus antarctica;;photosynthesis;;chlorophyll fluorescence;;temperature stress
摘 要：
Temperature was an important factor affecting the photosynthesis and geographical distribution of plant, and thus studying the influence of temperature on photosystem of Nothofagus antarctica will be very important for introduction and breeding.In this study, one-year-old seedlings of N.antarctica were exposed to different temperatures(-5℃, 5℃, 15℃, 25℃, 30℃, 35℃, 40℃). After exposed, chlorophyll fluorescence, rapid light curve and chlorophyll content of leaves, were analysed. With the stress aggravated, the performance of PSII activity(PIABS), the energy fraction of PSII used for photochemical reaction(P) and the maximal quantum yield of PS II electron transport(α) decreased, but the non-photochemical quenching(qN) increased, indicated that stress caused energy excess to leaves. In the mean while, the obvious K-peak and L-peak of the OJIP transient, and the flux of electrons transferred from QA-to PQ per active PSII(ETo/RC) was significantly decreased, suggested that oxygen-evolving complex and electron transport of PSII were disturbed. The dissipative energy ratio of non photochemical reaction(E), the fluorescence intensity of PSI(F1), the density of the active reaction centers per cross section(RC/CS), were increased by 110.0 %(P < 0.01), 178.1 %(P < 0.01) and 6.9 %(compared to 25 ℃) in 40 ℃, respectively. RC/CS and E were increased by 12.8% and 43.3%(P < 0.01) in-5 ℃, respectively. These indicated that the fluorescence intensity and the quantity of the active reaction centers were increased in response to stress. ETo/RC was the most sensitive parameter to stress, and the optimal temperature was 23.83 ℃ for N. antarctica photosynthesis from non-linear fitting result.
