中国对虾中肠盲囊的研究 Ⅱ中肠后盲囊的结构与功能

STUDIES OF MIDGUT CECUM OF PENAEUS CHINENSIS

运用石蜡切片和超薄切片技术，借助光学显微镜和电子显微镜观察中国对虾中肠后盲囊的组织和细胞结构；运用酶细胞化学技术，标记特异消化酶，探讨后盲囊的生理功能。认为（1）在蜕皮问期，中国对虾后盲囊结缔组织贮存来自中肠的营养物质，后盲囊上皮细胞可吸收结缔组织中的营养物质，经细胞内代谢作用，将部分代谢产物以上皮细胞顶端分泌的方式排入盲囊腔，再由盲囊外部的肌肉收缩，将这些代谢产物排入肠道。在上皮细胞的分泌物中，含有具细胞外消化功能的消化酶。（2）在蜕皮期，后盲囊结缔组织中贮存的营养物可由循环系统输送到机体需要养分的部位，以补充机体在禁食期对营养物的需求。因此，中国对虾中肠后盲囊具有调节对虾机体营养物平衡和分泌部分消化酶的功能。

The structural aspects of the posterior midgut cecum of penaeas chineasis wereexamined by using the optical and electron microscope on the paraffin and ultra^thinsections. And the physiological function was studied using enzyme cytochemistrytechnique by marking the specific digestive enzyme. The following conclusion wasobtained: (1) In the interphase of exuviation, the connective tissue stores up thenutrient which comes from the midgut, the epithelial cellsabsorb the nutrient fromthe connective tissue and excrete partial metabolin to the cecum cavity by way ofapocrine secretion after the intracellular metabolism, then, excrete the metabolinto the intestine as a result of the contraction of the external muscle of the cecum'there are digestiye enzymes in the secretory product of the epithelial cells andThey have the function of extracellular digestion. (2) In the phase of exuviation.the nutrient which has been stored up in the connective tissue of the posteriormidgut cecum is transported to the position where it is needed by the circulatorysystem in order to meet the nutritional need in the fasting phase. Therefore, theposterior midgut cecum of penaeas Chinensis has the function of adjusting thenutritive equilibrium and secreting partial digestive enzyme.Acknowledgments: The Authors thanks UNESCO for its support of this researchunder tile UNESCO confract No. 861. 359. 8