Morrison R L
Department of Physiology and Cell Biology, University of Kansas 66045-2106, USA.
Pigment Cell Res. 1995 Feb;8(1):28-36. doi: 10.1111/j.1600-0749.1995.tb00771.x.
Iridescent tissue colors are thought to be produced by iridophores through the optical phenomenon of thin-layer interference. Land and others have shown that structural features, predominantly reflecting platelet width and the cytoplasmic spacing between layers of platelets, determine the wavelength of light maximally reflected by this mechanism in iridophores. Some researchers have used interference microscopy to estimate these structural parameters, but the most direct measurement technique should be transmission electron microscopy (TEM). Transmission electron microscopy (TEM) has associated processing artifacts (particularly cytoplasmic shrinkage) that preclude direct measurement of ultrastructure, but if a number of assumptions are made, reflected wavelengths can be predicted. A thin-layer interference model and its associated assumptions were tested using TEM measurements of iridophores from several brightly colored tissues of each of three lizards (Sceloporus jarrovi, S. undulatus erythrocheilus, and S. magister). In all the instances examined when the contribution of the pigments present were accounted for, tissue color corresponded with predicted iridophore reflectances from the model. Finally, if the model and its assumptions are assumed to be correct, the amount of iridophore cytoplasmic shrinkage as a result of TEM processing can be calculated.
彩虹色组织颜色被认为是由虹彩细胞通过薄层干涉的光学现象产生的。兰德等人已经表明，结构特征，主要反映血小板宽度和血小板层之间的细胞质间距，决定了虹彩细胞中通过这种机制最大程度反射的光的波长。一些研究人员使用干涉显微镜来估计这些结构参数，但最直接的测量技术应该是透射电子显微镜（TEM）。透射电子显微镜（TEM）存在相关的处理假象（特别是细胞质收缩），这使得无法直接测量超微结构，但如果做出一些假设，就可以预测反射波长。使用来自三种蜥蜴（斯氏强棱蜥、红斑强棱蜥和巨头强棱蜥）每种蜥蜴的几种颜色鲜艳组织的虹彩细胞的TEM测量结果，对一个薄层干涉模型及其相关假设进行了测试。在所有检查的实例中，当考虑到存在的色素的贡献时，组织颜色与模型预测的虹彩细胞反射率相对应。最后，如果假设该模型及其假设是正确的，就可以计算出由于TEM处理导致的虹彩细胞细胞质收缩量。
