皱纹盘鲍贝壳沉积过程的研究

A Study of Shell Deposition of Abalone Haliotis discus hannai Ino

利用“平珠”生成法，通过对插入皱纹盘鲍（Haliotis discus hannai Ino）外套膜外腔中的玻片上沉积物质的分析，探讨皱纹盘鲍贝壳沉积的过程。利用扫描电镜（SEM）观察玻片上沉积物质的超微结构，傅立叶红外光谱（FTIR）分析玻片上沉积晶体的晶相，透射电镜（TEM）观察与玻片接触部分的外套膜的超微结构。结果发现：在将玻片插入外套膜外腔后的4～88h内．有机质首先在玻片上规则沉积。插入玻片88h后方解石晶体开始沉积，104h后出现圆形方解石晶体单位。8d后在方解石晶体表面出现文石晶体突起，15d后出现明显的堆垛型文石片层。27d后突然转变为方解石晶体的沉积。由此可见皱纹盘鲍贝壳的沉积具有一定的周期性，即方解石→文石→方解石的转变为1个周期。透射电镜观察外套膜结构表明在不同的插片时间，外套膜的超微结构不一样。插入玻片24h后．高柱状细胞中的内质网上的核糖体消失，高尔基体数量减少。3d后，大颗粒细胞增多，细胞内充满分泌颗粒。7d后，外套膜上皮细胞新分泌的有机质染色较浅。本研究证明了“平珠”生成法能够模拟贝壳的自然沉积，外套膜细胞超微结构的变化与贝壳沉积过程所处不同阶段有关。

The shell biomineralization process was studied by means of “flat pearl” inserting the coverslips into the mantle cavity of Haliotis discus hannai Ino. The microstructure of the deposition on the coverslips was analyzed by a scanning electron microscope （SEM）, the crystal phase of the deposition was analyzed by the fourier transform infrared spectroscopy （FTIR）, and the ultrastructure of mantle contacting with the ooverslips was observed by a transmission electron microscope （TEM）. During 4-88 hours after the coverslips were inserted into the mantle cavity, Matrix first deposited on the coverslips regularly. The calcite sheet appeared 88 hours later, and rounded calcite deposited on the coverslips 104 hours later. There was a transition from calcite to aragonite 8 days later, and obvious aragonite tablets appeared 15 days later. Abrupt transition to the deposition of calcite was found 27 days later. The ultrastructure of the mantle was changed after the insertion of the coverslips. The ribosome disappeared and the golgi-complex decreased in the tall columnar cells 24 hours later. Large granule cells increased, and full of secretory granules 3 days later. The new secretion produced by the mantle epithelium had low electron density 7 days later. It is demonstrated that the flat-pearl-culture method can simulate the mtural deoisition of shells. The change of the mantle ultrastructure is related to the shell deposition process.