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为探讨高温胁迫下仁用杏叶片的光合适应机制,以科尔沁沙地生长的4年生‘超仁’仁用杏为试材,设置环境温度为25℃、30℃、40℃和50℃处理,利用气体交换技术和快速叶绿素荧光诱导动力学曲线分析技术(JIP-test),研究了仁用杏叶片光合特性和PSⅡ光化学活性.结果表明:在一定温度范围内,随着温度升高,仁用杏通过提高光合色素含量和比例来维持光能的吸收、传递和转换能力,从而保证光合机构正常运转;当高温超过叶片自身生理调节限度后,叶绿素发生分解、净光合速率(Pn)明显下降、胞间CO2浓度(Ci)上升,说明光合作用的下降是由叶肉因素造成的.温度40℃导致单位面积有活性反应中心数量(RC/CSo)显著下降;而50℃高温下荧光诱导曲线中K点(Wk)和J点(Vj)明显增加,高温对仁用杏叶片放氧复合体(OEC)、受体侧和PSⅡ反应中心造成了伤害.此外,50℃高温还导致初始荧光(Fo)显著升高,为对照的2.26倍,PSⅡ最大光化学效率(Fv/Fm)和光化学性能指数(PIABS)分别下降为对照的37.9%和10.3%.高温损害了PSⅡ供体侧和受体侧的功能,造成光合效率下降,这是高温胁迫对仁用杏叶片光合机构伤害的主要机制之一.
In order to investigate the photosynthetic adaptation mechanism of apricot leaves under high temperature stress, four-year-old ’Chaoren’ apricot apricots grown in Horqin sandy land were used as materials to set the environmental temperature at 25 ℃, 30 ℃, 40 ℃ and 50 ℃, The photosynthetic characteristics and PSⅡ photochemical activity of apricot (Apricot) were studied by gas exchange technique and rapid chlorophyll fluorescence-induced kinetic curve analysis (JIP-test). The results showed that in a certain temperature range, with the increase of temperature, Apricot can maintain the function of light energy absorption, transfer and conversion by increasing the content and proportion of photosynthetic pigments, so as to ensure the normal operation of photosynthetic apparatus. Chlorophyll decomposes and the net photosynthetic rate (Pn) decreases obviously when the high temperature exceeds the limit of physiological regulation. The increase of intercellular CO2 concentration (Ci) indicated that the decline of photosynthesis was caused by the mesophyll factor, and the number of active reaction centers per unit area (RC / CSo) decreased significantly at 40 ℃. However, the fluorescence induced curve of K (Wk) and J (Vj) increased significantly, and high temperature caused damage to OEC, receptor side and PSⅡ reaction center of apricot leaves.In addition, the high temperature of 50 ℃ also caused the initial fluorescence (Fo) Significantly (Fv / Fm) and photochemical performance index (PIABS) decreased to 37.9% and 10.3% of the control, respectively.High temperature damaged the function of donor and donor side of PSⅡ, Resulting in decreased photosynthetic efficiency, which is one of the main mechanisms of high temperature stress on the photosynthetic mechanism of apricot apricot.