温度对辽东栎光系统Ⅱ的影响

Effects of different temperature on the photosystem II of the Quercus liaotungensis seedlings

[目的]本研究旨在探究温度对辽东栎Quercus liaotungensis幼苗光系统II(photosystem II;PSII)的影响规律。[方法]在单株尺度,采取逐渐改变环境温度的[方法],对叶片的相对叶绿素含量(SPAD)和快速叶绿素荧光进行测量分析;在区域尺度,利用辽东栎已知各地理分布点的最热月份最高温数据,对单株尺度的研究[结果]进行检验。[结果]叶片性能指数(PIABS)在5和45℃时大幅度下降,主要原因分别是PSII供体侧严重受损和PSII受体侧的能通量和电子传递效率严重降低。PIABS的温度响应曲线可依据Sine函数建立模型,模型预测PIABS的最适温度为28.1℃。164个辽东栎地理分布点的最热月份最高温的95%置信区间为27.1~28.3℃,PIABS温度响应模型预测的最适温度处于该区间内,预测结果可信度高。[结论]5℃和45℃的环境温度会对辽东栎1年生苗PSII造成严重胁迫;PSII光化学活性的最适温度为28.1℃。

[Objective]The purpose of this study was to clarify the temperature response mechanism of Quercus liaotungensis seedlings.[Methods]On the individual scale,relative chlorophyll content(SPAD)and chlorophyll fluorescence of the leaves collected from different seedlings were assessed when the environmental temperature was gradually changed to 5,15,25,35,and 45℃.On the regional scale,the highest temperature during the hottest month of Q.liaotungensis habitat was obtained,and was used to validate the results from the individual scale.[Results]The results demonstrated that PIABSwere severely impacted at 5℃and 45℃mainly due to the damage of PSⅡdonor side at 5℃and the significantly decreased energy fluxes and efficiencies of PSⅡreceptor at 45℃.The PIABS-temperature response curve could be modeled according to the Sine function,and the constructed model predicted the optimal temperature at 28.1℃.The 95%confidential interval for the highest temperature of the hottest month was 27.1~28.3℃based on 164 locations of Q.liaotungensis seedlings,and the predicted optimal temperature was fit into the range.Therefore,the prediction of constructed model is reliable.[Conclusion]This result showed that the temperature at 5℃or 45℃can badly damage the PSII photochemical activity of Quercus liaotungensis seedlings and the optimal growth temperature of seedlings was at 28.1℃.