雄性峨眉髭蟾“胡子”的组织结构特征

采用石蜡切片与苏木精-伊红染色及扫描电镜,对雄性峨眉髭蟾Leptobrachium boringii的角质刺及其周边皮肤进行了显微结构和亚显微结构的观察。显微结构观察发现,峨眉髭蟾的角质刺属于皮肤衍生物,突起呈倒"V"形。角质刺由表皮和真皮构成,表皮为复层扁平上皮,可分成4层;最外层细胞角质化,细胞轮廓不清,被染成深红色。真皮由疏松结缔组织构成,分辨不出致密层与疏松层,其内未见皮肤腺,但有少量色素细胞与毛细血管分布。表皮嵴伸入到真皮层,在以往的无尾两栖类研究中未见报道。角质刺基部可见皮肤褶翻起将其包裹在内,皮肤褶向上延伸形成角质刺。扫描电镜观察表明,角质刺顶端呈锥形的"小山丘"状,表面可分辨出表皮细胞轮廓,细胞为呈覆瓦状排列的角质化细胞。角质刺与皮肤交界处为多边形的角质化细胞。角质化上皮细胞的上表面与下表面均具有凹凸不平的花纹结构,细胞之间以镶嵌的方式连接。

Microstructure and Sub-Microstructure of the Keratinized Nuptial Spines of Male Leptobrachium boringii (Liu, 1945)

The microstructure and sub-microstructure of the keratinized nuptial spines and their relative peripheral skin of male Leptobrachium boringii were studied by general histological and scanning electron microscope (SEM) methods. The results showed that the spine of L. boringii is the skin derivative which rises up as an inverted V-like conical protuberance from the periheral skin area. Spine is composed of the external part of keratinized epidermis and inner part of dermis. The spine epidermis is stratified squamous epithelium and can be divided into 4 layers, of which the outermost layer is keratinized without cell outline and stained deeply red in color. The fold of skin encircles around the spine base and extends upward to form the spine. The spine epidermal ridge extends into the dermis under the epithermis. To the best of the authors' knowledge, this structure has never been reported in other studied frogs and toads. Furthermore, the underlying loose connective tissue of the epidermis makes up the spine dermis, where no stratum compactum and stratum spongiosum can be distinguished. In spine dermis, no skin glands were found but only a small number of pigment cells and capillary vessels. Under SEM observation, the tip of the spines looks like a conical "hill", and the outline of superficial epidermal cell is distinguishable in the surface. The cells arrange in imbricate pattern. At the junction of spine and its peripheric skin, the superficial epithermal cells are polygonous and keritinized. Both the upper and lower surfaces of keratinized epithelial cells have an uneven pattern. The cells are connected to each other with anchoring junctions.