怒江裂腹鱼鳃的显微和超微结构

通过光镜、扫描电镜及透射电镜技术,研究了怒江裂腹鱼(Schizothorax nukiangensis)鳃的组织结构和超微结构。结果表明,怒江裂腹鱼鳃基本结构与其他硬骨鱼相似,均由鳃耙、鳃弓、鳃丝以及鳃小片构成,且各部分具有不同的组织结构和细胞类型。扁平上皮细胞覆盖于整个鳃表面,其表面的纹路主要有3种类型,在鳃上不同的部位具有不同的结构和功能。线粒体密集细胞主要分布于鳃小片基部,仅有一种细胞类型,顶端膜内凹呈浅滩型,细胞内具有大量圆形的线粒体。怒江裂腹鱼鳃内扁平上皮细胞和线粒体密集细胞的形态结构与其在急流中游泳和摄食活动等生活习性相适应。本研究结果丰富了怒江裂腹鱼的基础生物学资料,并为阐明鱼类鳃的结构特征与其生活习性之间的关系提供参考。

Histology and ultrastructure of the gill in the teleost Schizothorax nukiangensis

The freshwater fish Schizothorax nukiangensis is a rare, endemic and economic species, only distributed in the middle and upper reaches of the Nujiang River (Upper Salween River) in China. Potential cascade hydropower development in the Nujiang River will threaten the survival of S. nukiangensis. The potential for drastic changes in the water flow, water temperature and food supply of their habitat may lead to extinction of S. nukiangensis. Therefore, biological research on future conservation and resource utilization is imperative. Herein, the histology and ultra-structure of the gill in the teleost S. nukiangensis was investigated using the optical and electron microscopic imaging techniques. The results showed that the basic structure of the gills consisted of the gill raker, gill arch, gill filament and lamellae, which was similar to other teleost fishes. Different parts of the gill possess distinct histological structures and cell types. The pavement cells (PVC) covered the filament epithelium and lamellae of the gills, showing three distinct morphological features of micro-ridges in the different parts of the gill. There was only one type of mitochondrial rich cells (MRC) observed in the gill, which were located at the base of lamellae. All these MRC have a large number of big, round mitochondria and exhibit apical shallow-basin with microvilli. Our results suggested that the morphological feature and functional diversity of PVC and MRC in the gill of S. nukiangensis were in accordance with its habitat. These observations enrich the basic biological knowledge of S. nukiangensis and can provide a reference for clarifying the relationship between the specific structural characteristics of the fish and their living habits.