【摘要】 为了解淡水珍珠的成珠过程,采用环境扫描电子显微镜对开膜法养殖异形淡水珍珠样品的表面微形貌特征进行了观察。结果显示,在异形淡水珍珠样品珍珠层中,成层排列的文石板块形状各异,具有多层和有序的特点;在珍珠层的生长初期,形成于成核小片上的有机质为三角帆蚌外套膜细胞所分泌,其为后期矿物提供进一步沉淀的局限空间和成核作用的基底,具有确定矿物成核大小、空间排列、结晶取向和离子堆积是否出现同质多象的功能。同时,珍珠样品表面出现了与在海水珍珠和以淡水池蝶蚌为母贝的淡水珍珠中类似的螺旋生长纹,这可能是其在生长过程中受有机质的调控作用,使文石晶体在不同部位上的堆积具有差异性,也使文石晶体在特定面网方向上生长,控制了其成核结晶取向和堆叠方式,导致其螺旋堆积,形成类似螺旋纹的生长外观。更多还原

【Abstract】 In order to investigate the formation process of freshwater cultured pearls,the surface microtopography characteristics of abnormal-shape freshwater cultured pearls by inserting technology are observed by using the environmental scanning electron microscope(ESEM).The results show that the shapes of aragonite templates with layer arrangement in the nacreous layer of abnormal-shape freshwater cultured pearl samples are various,multilayered and orderly.At the initial stage of the nacreous layer growth,the mantle cells of Hyriopsis cumingii secrete the protein on surface of the nucleation pieces,which provides the matrix and limited space for the minerals in advanced stage,and plays a vital role in mineral nucleation,space arrangement and crystallization orientation.The protein also functions as determining whether there would be homogenous mineral in ion accumulation.A spiral structure,similar to that of seawater pearls or Hyriopsis schlegeli cultured pearls,appears on the surface of the freshwater cultured pearl samples,which might be affected by the regulatory functions of the protein in the growth process.As a result,the aragonite accumulation in different locations is variable,the aragonite crystals grow in the specific lattice direction,and their crystallization orientation and nucleation pattern are controlled,leading to their spiral accumulation and spiral appearance.更多还原