[The comparison study on the preparation of chromosomes of the freshwater prawn Macrobrachraium nipponense (Crustacea, Decapoda)].

Abstract

The Chromosomes of Macrobrachium nipponense had been prepared using the materials of testis or embryo with the chromosome low-osmosis method or cell low-osmosis method. After 5.5 h, the bivalents at meiotic diplotene were appeared. The comparison of the two methods for two different materials showed that the morpha of the chromosome of testis using the low-osmosis method was better than that of using the cell low-osmosis method. Contrarily, the low-osmosis was better than the cell low-osmosis for the morpha of the chromosome of embryo. The bivalents at meiotic diplotene were rod-shaped, and centromere position could be identified easily at that time. The diploid chromosomes numbers were 104. The chromosome formula was N=11M+26SM+4ST+11T. The technique of the chromosome preparation of Macrobrachium nipponense was preliminarily discussed as well.