Pollen-statistics a new research method in Paleo-ecology
Pollen-statistics a new research method in Paleo-ecology
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DOI：
10.1126/science.73.1893.399
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发表时间：
1931-04-10
期刊：
影响因子：
56.9
通讯作者：
Erdtman, G.
中科院分区：
文献类型：
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作者：
Erdtman, G.
实验室工作当准备进行显微镜研究时，从封闭在玻璃管中的物质的两端取少量泥炭，放在载玻片上，与10%的苛性钾混合。用衣夹夹住载玻片，将混合物小心地在小酒精火焰上煮沸，直到大部分水蒸发。然后加入几滴甘油并与泥炭混合，并将一部分混合物移到另一个载玻片上，并用盖玻片覆盖。然后使用显微镜的微米台对花粉粒进行计数。放大。需要大约200倍的放大率，然后需要高倍透镜来研究外壁的更精细的细节。有些沉淀物不需要煮沸，只需将一部分物质与蒸馏水混合即可制备。石灰质材料用稀盐酸处理，成矿土，甚至相当粗的砂，如果离心并用盐酸处理，就可以进行花粉分析。如果计数约150个花粉粒，就可以得到可信的百分比。榛、柳树和其他多少局限于林下的树种的花粉粒频率是分别计算的，并表示为占林木花粉粒总数的百分比。因此，杨柳花粉的频率为138%，表明该制剂中杨柳花粉粒的数量大于林木花粉粒的总和。泥炭藓孢子、四分体等的出现频率较高，都是以同样的方式表达的。记录每种制剂的PF或每平方厘米的花粉频率也是有用的。用百分率法绘制花粉图。样品中花粉种的相对频率数构成了样品的花粉谱。根据从沼泽钻孔中采集的一系列花粉光谱，可以绘制一个花粉图，以泥炭深度为纵坐标，在与取样水平相对应的横坐标上绘制花粉百分比。在花粉图中，单个种或一组种的曲线既直观地表示花粉植物群的组成，又直观地表示沼泽形成期间在花粉曲线之间发生的频率振荡。
THE LABORATORY WORK When preparations for microscopical investigation are to be made, a small amount of peat is taken from each end of the substance enclosed in a glass tube, laid on a slide and mixed with 10 per cent. caustic potash. The slide is held with a clothes pin and the mixture is carefully boiled over a small alcohol flame until the greater part of the water has evaporated. Some drops of glycerine are then added and mixed with the peat, and a part of the mixture is removed to anotherslide and covered with a cover-glass. The pollen-grains are then counted by the use of the micrometer stage of the microscope. A magnification. of about 200 times is required, and then a high power lens for the study of the finer details of the exine. Some sediments need no boiling and preparations are simply made by mixing a part of the substance with distilled water. Caleareous material is treated with dilute hydrochloric acid and minerogene earths, even rather coarse sand, could be subjected to pollen-analysis if centrifugated and treated with hydro-fluoric acid.Trustworthy percentages are obtained if about 150 pollen-grains are counted. The frequency of the pollen-grains of hazel, willows, and other species which are more or less confined to the under-growth of the forests, is calculatedseparately and expressed as a percentage of the sum of the pollen-grains of the forest trees proper. Thus, a willow pollen frequency of 138 per cent. indicates that the number of willow pollen-grains in that preparation was bigger than the sum of the pollen grains of the forest trees. The frequency of Sphagnum spores, tetrads of Er-eaceae, etc., is expressed in the same way. It is use-ful, too, to have a record of the PF, or pollen frequency per square cm, from each preparation. By means of the percentage figures, a pollen-dia-gram isconstructed. The relative frequency numbers, which are produced for the pollen-species found in a sample, constitute thepollen-spectrum of the sample. On the basis of a series of pollen-spectra from a boring in a bog, a pollen-diagram may be constructed, with the depth of the peat as ordinate and thepollen percentages plotted down on abscissae corresponding to those levels from where the samples were taken. In a pollen-diagram the curves for the single species or for a group of species give both a visual representation of the composition of the pollen flora and the oscillations as regards frequency which have taken place reciprocally between the pollen-curves during the formation of a bog.