浮游植物叶绿素a含量简易测定方法的比较

用乙醇、DMF(N,N-二甲基甲酰胺)、丙酮3种不同有机溶剂分别萃取苏州环城河水样中的浮游植物细胞叶绿素a,在分光光度计上测定其叶绿素a含量,试验数据经方差分析、Q检验,结果显示,乙醇法、DMF法的叶绿素a萃取率极显著高于丙酮(F=54.20＞F0.01(2,18)(6.01)).另用这3种萃取方法分别测定无常蓝纤维藻(Dactylococcopsis irregularis )纯培养液叶绿素a含量,通过直线回归,同样证明乙醇法、DMF法重复率较高,稳定性好,萃取率高.从安全、简便、重复性高等方面综合考虑,认为用乙醇萃取法是目前水域环境中浮游植物叶绿素a简易测定的最佳方法.

Comparison of simple methods for extraction and measurement of phytoplanktonic Chlorophyll-a

Chlorophyll-a(Chl-a) concentration is generally used as an estimate of phytoplankton biomass. Based on the fact that Chl-a is soluble in organic solvents and absorbs light at certain wavelengths, Chl-a concentration can be measured by the classic spectrophotometric method. Water samples were collected from moat river in Suzhou to determine phytoplanktonic Chl-a concentrations. The extractions of Chl-a with ethanol, DMF(dimethyl sulfoxide) and acetone were carried out, respectively, and the Chl-a concentration was measured spectrophotometrically. The data were analyzed by analysis of variance followed by Q test. The results show that the efficiencies of Chl-a extraction with ethanol and/or DMF are significantly higher than that with acetone(F=54.20>F_0.01(2,18)(6.01)). Additionally,pure cultures containing Dactylococcopsis irregularis were also used to determine Chl-a contents, the results analyzed by linear regression supported that extractions with ethanol and/or DMF were more excellent than that with acetone in repeatability, stability and efficiency. When safety,convenience, and repeatability involved in the extraction and measurement procedures were taken into consideration, we suggest that ethanol be the optimal solvent for extracting phytoplanktonic Chl-a.