企鹅贝附壳珍珠表层螺旋生长结构的原子力显微镜研究

Study of Spiral Growth Structure of Nacreous Layer from Pteria Penguin and Blister Pearl by AFM

采用原子力显微镜(AFM)对海南三亚企鹅贝及其附壳珍珠(包括马氏贝和淡水蚌及淡水珍珠)表层的微形貌进行了观测。结果显示,从珍珠层内侧—外侧边缘,螺旋生长结构有明显的变化,其形态受控于螺旋圈层间距的大小、数量、方向及临界二维核的半径,推测与生物体在不同部位上有机质的导向与调控作用有关;在其表层还发育较完整的同心圆状生长结构,推测可能是螺旋生长结构的准稳定状态;在AFM下文石呈柱状群集生长,可明显地观察到每个文石晶体之间高度差异的纳米级三维实空间图像,进一步说明了在纳米尺度上文石晶体沿其结晶取向呈螺旋堆砌生长。结合相关的研究内容和借鉴传统的螺旋位错生长理论(BCF理论)与三维成核生长机制,尝试建立一种螺旋生长模式。

The surface microtopography of the nacreous layer from Pteria Penguin and blister pearl（from Sanya, Hainan Province）, including Pinctada Martensii, Hyriopsis Gumingi and freshwater cultured pearls, are observed by using atomic force microscope（AFM）. The results show that the characteristics of size, quantity, orientation and the semidiameter of critical planar nucleus of spiral growth structure from the inner to the outer nacreous layer of the shells are obviously different, which could be related with the organic matrix. The growth structure of concentric cinularity also exits on the surface, which could be the steady state of spiral growth structure. The aragonite crystallite is of column for growing collectively and the height of each one is also different from nan-three-dimensional space image, proving aragonite crystallite being spiral piled along the crystallo-graphic orientation. According to the study before, on the basis of BCP theory and 3-D nucleation growth mechanism, a mode of the spiral growth structure is established tentatively.