乌龟卵壳结构的研究

Study On The Structure Of Shells From Eggs Of Chinemys Reevesii

本文对乌龟卵壳在扫描电镜下的微观结构进行了研究.乌龟卵壳主要由钙质层与壳膜组成.钙质层由霰石状态的碳酸钙晶体组成,可分为许多个壳单位,每个壳单位由同一中心辐射出来的针状晶体构成.卵壳的外表面具有一定的饰纹,有些部位还分布有纵横交错的有机纤维和块状的有机物质.壳膜由多层网状纤维组成,没有内、外壳膜之分.龟卵在孵化过程中不形成气室.同时对孵化前后龟卵壳的结构进行了对比研究.

Observations on the microstructure of eggshell of Chinemys reevesii with scanning electron microscopy were conducted.The rigid-shelled eggs have calcareous layers composed of calcium carbonate in the form of aragonite.The calcareous layer is organized into individual shell units with needle-like crystallites radiating from a common center.Pores are among shell units, but the morphology and distribution of pores exhibit variability at different sites of eggshell.Most of the thickness of the eggshell is attributable to the calcareous layer, with the shell membrane comprising only 26.11% of the shell thickness.The outer surface of the eggshells is sculptured, and has organic fiber networks and organic layers at some sites.The shell membrane consists of many layers fibers, but we have found no evidence that eggs of C reevesii have both an inner and an outer shell membranes.Eggs incubated rarely form an air cell.The shell membrane detaches from eggs incubated, earring with the remnants of the calcareous layer.Such changes in shell structure presumably reflect the withdrawal of calcium from the eggshell by the developing embryos.