合浦珠母贝鳃的显微与超微结构

合浦珠母贝(Pinctada fucata)是典型的滤食性瓣鳃类动物,也是我国重要的海水珍珠养殖贝类。本研究用光学显微镜、扫描电镜和透射电镜观察了合浦珠母贝鳃的显微和超微结构。结果表明,合浦珠母贝鳃结构属于异丝鳃型,左右两侧各2个鳃瓣,每个鳃瓣由内鳃瓣和外鳃瓣组成。鳃瓣由主鳃丝和普通鳃丝构成,主鳃丝在鳃瓣中主要起支架作用,每2根主鳃丝之间的9～12根普通鳃丝由"簇内连接"(intrabunchial junction)相连成簇。普通鳃丝之间通过"丝间连接"(interfilament junction)相连,丝间连接的上皮细胞与普通鳃丝的扁平细胞结构一样,为鳃的呼吸上皮。丝间连接的存在扩大了鳃的表面积,这种结构有助于进行气体交换。主鳃丝和普通鳃丝表面有前纤毛和侧纤毛,与食物运送和气体交换有关。普通鳃丝表面的纤毛为典型的"9+2"型微管结构。

Microstructure of the Gill in the Pearl Oyster Pinctada fucata

The pearl oyster Pinctada fucata is a typical filter feeder, and is also an important marine pearl-producing oyster. In this study, the histological structure of the gill tissue in P. fucata was studied using light microscopy and electronic microscopy for the first time. The gill belongs to heterorhabdic gill type which is composed of two pieces of gill lamellas on each side of the shell cavity, i.e. inner and outer gill lamellas. The gill lamella consisted of two kinds of gill filaments-principal and normal gill filaments. The principal filaments play a supporting role in the demibranch. Nine to twelve normal gill filaments are grouped into a cluster by intrabunchial junctions between every two principal gill filaments. The normal gill filaments are linked by interfilament junctions. The epithelial cells of the interfilament junctions are a kind of flat respiratory epithelial cell, the same as that of the normal gill filaments. The existence of the interfilament junctions expands the surface area of the gill, which is helpful for exchanging air. The frontal cilia and lateral cilia on the surface of the gill filaments are responsible for carrying food particles and exchanging air. The surface cilia of normal gill filaments is a typical "9+2" microtubules structure. The results provided a background for further research on the relationship between the structure and function of gill in the pearl oyster P. fucata.