How to study fucus



Material for habit study may be dried, or preserved in formalin, or mounted on paper. In the latter case, glue or gummed paper will be necessary.

Fertilization occurs at all seasons, but autumn is the most favorable, In summer the material dies before it reaches Chicago, but during the rest of -the year a pailful will reach Chicago, and even as far west as the Mississippi River, in good condition for showing the rotation of the egg by the sperms. The eggs and sperms form slimy masses the antheridia being orange red, and that containing the eggs a dirty green. Mix a drop of the red with a drop of the green. The movements of the egg can be observed, and material for a study of fertilization and later stages is easily secured. In fixing fertilization and succeeding stages, it is worth while to use some of the regular Flemming's weaker solution, as well as the solution without the osmic acid.

For the growing points and conceptacles, small pieces should be cut off with a razor. If the fruiting tips be cut through lengthwise before they are cut off, the fixing will be more satisfactory. For sections of the conceptacles it is better not to cut across the whole tip, but to cut off pieces of the rind containing half-a-dozen conceptacles. Such pieces are more easily imbedded and cut. There is no difficulty in cutting such pieces in paraffin. Iron-haematoxylin is a good stain. Safranin and gentian-violet are also satisfactory, but care must be taken not to overstain since Fucus usually stains deeply and rapidly.

For the cytologist, Fucus might be used as a test object for testing proficiency in technic, just as Pleurosigma angulatum is used in testing an objective. The nuclear divisions in the antheridium are simultaneous, and at the sixth division, which is the last, there are 32 mitotic figures, each with 32 chromosomes which split so that 32 go to each pole. When you can make a preparation in which these chromosomes can be counted, your technic is adequate for research work in cytology. In a good preparation, the mitotic figures in the oogonium show small but brilliant centrosomes, with a great display of radiations.





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