STUDIES ON THE SILVER-STAINED KARYOTYPES OF 7 SPECIES IN CYPRINIDAE (PISCES)
鲤科七种鱼的银染核型研究

Silver-stained karyotypes of 7 spacies of cyprinid fishes, namely Xenocypris argentea, X. davidi, X. sechuanensis, X. fangi and Plagiognathops microlepis of Xenocyprininae, Paracanthobrama guichenoti of Gobioninac and Elopichthys barnbusa of Leuciscinae were studied. 4 NORs were found in all of these species. The features of the NORs among the 5 species in Xenocyprininac are alike. The location and morphology of NORs arc consistent with secondary constrictions on the chromosome sm3 of P. guichenoti. The relative size of NORs between the homologues sm6 of E, bambusa is apparently different. Based on the results of silver-stained karyotype studies in this paper and the data from conventional karyotype analyses reported by us previously, the polymor phisms of NORs in fishes, phylogenetic relationship of some species in Leuciscinae and chromosome evolution in Xenoeyprininae have been discussed.