小地老虎成虫直肠的发生和直肠乳突细胞功能性分化

本研究观察了小地老虎Agrotis ypsilon末龄幼虫、预蛹、蛹和成虫的直肠结构及成虫直肠乳突的细胞结构特点。结果表明：(1)成虫直肠是由幼虫的隐肾复合体解体后，原有幼虫直肠细胞经过分裂、重组和分化形成的，关键时期是预蛹至化蛹5d；(2)成虫直肠乳突呈圆盘形，自内向外包括内膜、乳突细胞、底膜、肌肉和围膜5层。乳突细胞按结构和功能特点分为帽状细胞、微气管细胞、网状细胞和盘底细胞4种；(3)试验发现成虫直肠膨大是由乳突体积扩增引起的。细胞结构剖析，直肠乳突有一整套完整而精细的结构，能扩增乳突体积和供应足够氧气及营养。文中还讨论了直肠的多种生理功能。

ADULT RECTUM GENERATION AND FUNCTIONAL DIFFERENTIATION OF RECTAL PAPILLARY CELLS IN THE BLACK CUTWORM AGROTIS YPSILON

The generation of adult rectum and functional differentiation of rectal papillary cells in the black cutworm (Agrotis ypsilon) were studied with light andelectron microscopes.Attention has been paid on their histological and cytologiralchanges in sixth instar larvae,prepupae,pupae and adults.The results are summarized as follows:1.Adult rectum was generated after the larval cryptonephridial complexdegenerated. Larval rectal cells rapidly divided,reconstructed and differentiatedduring the prepupal and early pupal stages so that adult flat rectum cells anddiscal rectum papillae were formed.2. Adult rectum papilla was discal and consisted of five layers of cuticleintima, papillary cells, basal lamella,muscle and peritoneal membrane.Papillary cells were divided into four types: cap cell,tracheolar cell, netty cell and discalbase cell.3.In our study it is found that adult rectum expands owing to the papillaryvolume enlarging.A series of delicate constructure enable papillary cells to enlargein volume and provide oxygen and nutritent supply.