甲醛与戊二醛固定剂对基于Ludox–QPS染色方法的研究结果对比

Comparison of the fixation effect of formaldehyde and glutaraldehyde on the Ludox–QPS method

为检验甲醛与戊二醛固定并经Ludox–QPS(Ludox Density Gradient Centrifugation Combined with Quantitative Protargol Staining,硅胶提取结合定量蛋白银染色)染色后的微型底栖动物群落研究结果是否具有可比性,本研究于2019年4月对采自长江口湿地3种自然生境(海三棱藨草滩、光滩和沙滩)的底栖纤毛虫群落,分别用终浓度1%的甲醛与2%的戊二醛进行固定后,通过ANOSIM(Analysis of Similarities,相似性分析)双因子(固定剂类型与生境类型)交叉分析方法,检验两种固定剂固定的群落在物种组成、生物量和多样性上的差异.研究结果表明:虽然不同生境之间纤毛虫群落结构存在显著差异,但固定剂类型对其群落的物种组成、多样性参数(物种数、个体数、均匀度、香农–维纳指数)以及生物量均无显著影响.NMDS(Non-metric Multidimensional Scaling,非度量多维尺度)分析结果(stress=0.11)也显示,两种固定剂固定的纤毛虫群落物种组成相似.以上结果表明,这两种固定剂获得的底栖纤毛虫群落,在经过Ludox–QPS染色后的研究结果具有可比性.因此,甲醛溶液也可用于微型底栖生物样品的固定.

Density gradient centrifugation in combination with quantitative protargol stain(Ludox–QPS)is an important research method for the separation,extraction,and staining of microbenthos.Glutaraldehyde solution is the most widely used fixative for this method;however,it is a hazardous chemical and transportation by civil aviation is forbidden.Hence,biogeography studies using glutaraldehyde solution on a large scale are greatly limited.In contrast,samples fixed with formaldehyde solution can be transported by air consignment under certain conditions.To test whether the results of a study on microbenthic communities fixed with formaldehyde and glutaraldehyde are comparable,we collected microbenthic samples from three natural habitats(bare mudflat,Scirpus mariqueter meadow,sandy beach)and fixed them with either formaldehyde(final concentration is 1%)or glutaraldehyde(final concentration is 2%).Then,we tested the significance of differences in species composition,diversity,and biomass of the communities using an ANOSIM two-way crossed analysis(fixative type and habitat type).The results of this study demonstrate that although significant differences exist in the community structures among the three habitats,the species composition,diversity indices(number of species,number of individuals,evenness,Shannon-Wiener diversity index),and biomass of the microbenthic communities between the two fixative types have no significant differences.NMDS analysis also shows similar results(stress=0.11).In conclusion,the data indicates that the microbenthic communities fixed by the two fixatives are comparable.Therefore,formaldehyde is also suitable for ecological research of microbenthos as a fixative.