Observation on silver-staining nucleoli in different ploidies of large yellow croakers(Pseudosciaena crocea Richardson)

Using Ag-staining technique, the nucleoli in interphase cells from different developmental stages (embryo, larva or adult) of large yellow croaker (Pseudosciaena crocea Richardson) were observed and counted, which were in different ploidy levels, including haploid, normal diploid, triploid, gynogenesis diploid and triploid whose mother were gynogenesis diploid. The maximum numbers of nucleoli kept even in the same ploidy samples at different developing stages (embryo, larva or adult), as well as in different tissues(gill, kidney, fin) in any individuals. The maximum numbers of nucleoli of non-gynogenesis fishes (normal diploid and triploid) were 2 and 3 respectively. But it was interesting that the maximum number of the nucleoli from gynogenesis fishes ( gynogenesis diploid with 1 and gynogenesis triploid with 2) were one fewer than that of the non-gynogenesis fishes with the same ploidy level, and this phenomona would be deserved deep investigation. The results indicated that the numbers of nucleoli within cells at different ploidy fishes were highly correlated with their ploidy level. Therefore, as a simple and accurate method,silver-staining nucleoli counting could be widely used to identify the ploidy level in fish.