生长季油松针叶叶绿素荧光对温度变化的响应

针对华北地区常绿树种油松耐严寒酷暑的特性，测定生长季针叶叶绿素荧光随短时温度胁迫的变化规律，以探讨油松光合机构对异常温度波动的响应特性。结果显示:在30 和35 ℃常见高温下，随温度升高，初始荧光(F0)、非光化学淬灭系数(qN)逐渐上升，最大光化学效率(Fv/Fm)、最大量子产额(Yield)、电子传递速率(ETR)逐渐下降，变化的幅度较平稳，表明夏季常见高温可影响油松针叶PSⅡ的活性，但造成的损伤不大；而40 ℃以上的高温胁迫，F0、qN上升与Yield、ETR下降的幅度明显增大，Fv/Fm降低到0.8以下，表明针叶的光合机构受损严重。在零上低温(0~15 ℃范围)胁迫下，随温度降低各参数变化不明显，表明生长季油松PSⅡ对零上低温的扰动较稳定；零下低温胁迫时，Fv/Fm、ETR、Yield、qN急剧下降，F0显著上升，且这种损伤是不可恢复的，表明油松PSⅡ在生长季对零下低温是敏感的。 

Response of chlorophyll fluorescence of Pinus tabulaeformis Carr. needles in growing seasons to temperature changes.

Pinus tabulaeformis Carr. is a species of evergreen plants with the characteristics of heat and cold resistance in north China. The changing patterns of its needles chlorophyll fluorescence parameters after various temperatures were investigated in order to find out how the needles photosynthetic institution respond to unusual temperatures. The data showed that when needles were subjected to 30 and 35 ℃, the minimal fluorescence (F0) and the non photochemical quenching coefficient (qN) increased by degrees, while the maximal quantum yield of PSⅡ(Fv/Fm), the maximum quanta yield (Yield), and the electron transport rate (ETR) decreased gradually as the temperature went up. Whereas, all the data varied within a small range, indicating that common high temperature in summer had effects on the PSⅡ reaction centre activity, but cause slight damage. However, when dealt with over 40 ℃ high temperatures, F0, qN ascended and Yield, ETR descended sharply, meanwhile, Fv/Fm reduced to the value below 08. This suggested that the PSⅡ reaction centre might have suffered severe damage. When subjected to low temperatures above zero (ranged from 0 to 15 ℃), parameters didnt have notable changes. That is to say, PSⅡ reaction centres activity of the needles in growing seasons can be stable to the above freezing temperatures influence. Under subzero temperatures, Fv/Fm, ETR and qN decreased considerably while F0 increased visibly, and didnt have significant recovery in the next 12 hours, which implied that subzero temperatures have done irreversible harm to the photosynthetic institution of P. tabulaeformiss needles.