采用三维荧光光谱和Δλ=20 nm同步扫描荧光光谱技术研究Hg2+, Cd2+, Cu2+, Zn2+胁迫作用下蛋白核小球藻(Chlorella pyrenoidosa)荧光光谱的变化情况, 两种光谱技术得到了较为一致的结论: 即胁迫作用96 h后, 蛋白核小球藻荧光中心处的荧光值显著降低, 四种重金属离子对藻细胞光合系统的叶绿素a和叶绿素b造成了严重的破坏。 进一步分析四种重金属离子浓度与由同步扫描荧光光谱得到的藻荧光猝灭效率I0/I的相关性可知: 重金属离子的毒性与荧光猝灭效率I0/I呈正相关关系, 均随重金属离子浓度和胁迫时间的增加而增强。 对某一种重金属而言, 同步扫描荧光光谱可实现藻细胞对该重金属毒性的评价。 与三维荧光光谱相比, 同步扫描荧光光谱具有耗时少、 对特定荧光中心选择性高等优点, 是研究水体有毒污染物毒性的有利工具。

Spectrofluorometry of chlorella pyrenoidosa was studied by three dimensional excitation-emission (3DEEM) fluorescence spectroscopy and synchronous scan fluorescence spectroscopy with Δλ=20 nm in the stress of Hg2+, Cd2+, Cu2+ and Zn2+. The conclusion from two kinds of Spectrofluorometry was the same: after 96h stress by heavy metals, the maximum fluorescence values reduced obviously, chlorophyll-a and chlorophyll-b in the photosynthetic system were seriously damaged by heavy metal. Further analysis of the correlations between heavy metal concentration and fluorescence quenching efficiency I0/I can conclude that the toxicity of heavy metal and the fluorescence quenching efficiency I0/I were positively correlated, and they all increased with the heavy metal concentration and stress time. For one kind of heavy metals, synchronous scan fluorometry is a sensitive method for its toxicity assessment. Compared to 3DEEM fluorescence spectroscopy, synchronous scan fluorescence spectroscopy is less time consuming and of higher selectivity. It is suitable to assess the toxicity of pollutions in water.