贻贝棘尾虫口器的结构  

STRUCTURE OF ORAL APPARATUS IN STYLONYCHIA MYTILUS

作　　者：隋淑光[1] 陈瑛[1] 邱子健[1] 史新柏[1] 

机构地区：[1]哈尔滨师范大学生物学系,哈尔滨150080

出　　处：《动物学报》2001年第4期436-441,共6页ACTA ZOOLOGICA SINICA

基　　金：国家自然科学基金资助项目 (No .396 70 0 91)&&

摘　　要：利用半薄连续切片和超薄切片对贻贝棘尾虫口器的显微及亚显微结构进行了观察。澄清了口侧膜和口内膜的立体位置。它们均为纤毛膜。口侧膜发自内唇的边缘 ,由两排纤毛构成 ,口内膜发自口围右壁 ,紧贴口围顶壁向左伸展 ,由单排纤毛组成。在口内膜的腹侧发现一非纤毛厚膜 ,暂定名为吞噬辅助膜 ,它由两层质膜夹一纵行微管束层构成 ,至口围后部口围带内收之处 ,此膜再向腹侧延伸出第二个膜 ,共同构成括号状 ,至胞口处此膜与口内和口侧膜互相包卷而成一包卷体 ,共同进入胞咽。经分析认为此膜及其与两纤毛膜形成的包卷体 ,对棘尾虫摄取大的固体食物起重要作用。The microstructure and ultrastructure of oral apparatus in Stylonychia mytilus were observed by means of continuous semi-ultrathin and ultrathin transverse sections.In contrast with light microscopic observation on protargol preparation of the whole oral apparatus,the stereoscopic positions of each buccal organelle were clarified. Both paroral mebarane (PM) and endoral membrane(EM) were made of cilia.PM originated from the edge of inner lip (IL) and containd two files of cilia.The EM originates from the right wall of peristome (PST) and stretched to the left side in a way of closely nearing the top of PST.It was formed by a file of cilia.A non-ciliary thicker membrane tentatively named phago-assistant membrane (PAM) was found in the ventral side of the EM.It was formed by two layers of membrane and a longitudinal microtubule bundle layer between them.In posterior region of the peristome where the adoral zone of membranelles(AZM) had turned to the mid ventral surface,the phago-assistant membrane extended to the ventral side into a second membrane,they formed together a bracket-shaped membrane.At the cytostomal level,the phago-assistant membrane separateed itself from the cytostomal wall,and the cilia of endoral membrane and paroral membrane assumed a lengthened growth,three membranes tightening into a bundle and entering the cytopharynx(CPH).Sometimes,Stylonychia mytilus could engulf a food even as large as itself.For a long time,how could so large a food pass through such a narrow cytopharynx and the dynamic mechanism of this process perplexed researchers.The discovery of the phago-assistant membrane and the understanding of the stereoscopic structure of the oral apparatus make it possible to explain the possible mechanism of engulfing larger food in Stylonychia mytilus.Phago-assistant membrane may play an important role in this process.We argue that the phago-assistant membrane looks like a palisade that is made of microtubule.To some extent,it possibly expanded itself when food particle or larger food body was

关 键 词：贻贝棘尾虫 口器结构 摄食功能 

分 类 号：Q959[生物学—动物学]