基于叶绿素荧光技术的紫菜光适应特征研究

摘要

通过水样调制式叶绿素荧光仪,对坛紫菜、条斑紫菜叶状体和丝状体在不同光照条件下叶绿素荧光特性进行研究.结果表明:紫菜叶状体和丝状体实际量子效率在光照处理后逐步下降,且随着处理光强的上升,实际量子效率的下降速率更为明显.快速光曲线初始斜率(α)结果与实际量子效率相似,表明光照时间的延长以及光照强度的升高均引起样品实际光能利用效率的下降.快速光曲线结果也显示样品半饱和光强低于150 μmol/(m2·s),说明紫菜这类海藻偏向较低光强的适应性.随着处理光强的上升,样品Ik值逐步升高,说明紫菜具备适应光强变化的光能调节机制.方差分析结果表明,两种紫菜丝状体实际量子效率、快速光曲线初始斜率(α)和最大相对电子传递速率均因光强的上升而显著降低(P＜0.05),叶状体实际量子效率、快速光曲线初始斜率也随光强上升而下降,但最大相对电子传递速率基本维持不变,表明紫菜两个生长世代的藻体对光强具有不同的响应机制.诱导曲线测定结果表明,经强光适应的紫菜叶状体光化学猝灭较高,而非光化学猝灭较低,显示强光处理能够提高叶状体对光强的适应能力.%The chlorophyll fluorescence characteristics of thallus and eonchocelis in both species of Por phyra grown under different light intensities were investigated with Water-PAM chlorophyll fluorometer.Results showed that the effective quantum yield of PSⅡ (Yield) of Porphyra decreased after the treatment, and the effective quantum yield of sample decreased obviously with the increasing of light intensity.Results of the initial slop of rapid light cnrvc (α) are sirnilar with the effective quantum yield of sample,which meant both the time after treatment and the increasing of light intensities Would induce the decreasing of actual light energy use efficieney of Porphyra.lhe minimum saturating irradiance (Ik) calculated from the rapid light curves (RLC) of thallus and conehoeelis in Porphyr were leas than 150 μmol · m-2·s-1, which indicatcs Porphyra was one kind of seaweed adapted to Iow light intensity.High PAR in creased the Ik of Porphyra,which supported the idea that Porphyra had light energy regulatory meeha nism to adapt to thc changes of light intensities.ANOVA results showed that the effective quantum yield of PSⅡ, the initial slope of rapid light curve (α), the maximum relative clectron transport rate (rETRmax) of conchocelis in both species of Porphyra decreased signifieantly with the increasing of light intensities(P＜0.05), the effective quantum yield of PSⅡ and the initial slope of rapid light curve of thallus also decrcased with the increasing of light intensity, but the maxbmum relative electron transport rate had little change,which meant conchocelis and thallus of Porphyra might have different response mechanisms to the changes of light intensities.The results of induce curve indicated that thallus of both species of Porphyra grown under high light intensity had higher photochemical quenching (qP) and lower non-photocbemical quenching (NPQ) than those grown under low light intensity, which suggested that the light tolerance of thallus of Porphyra could be improved by high light intensity acclimation.