The objective of the present study is to examine the fine structure of vegetative cells of Laminaria digitata using both chemical fixation and cryofixation. Laminaria digitata was chosen due to its importance as a model organism in a wide range of biological studies, as a keystone species on rocky shores of the North Atlantic, its use of iodide as a unique inorganic antioxidant, and its significance as a raw material for the production of alginate. Details of the fine structural features of vegetative cells are described, with particular emphasis on the differences between the two methods used, i.e. conventional chemical fixation and freeze-fixation. The general structure of the cells was similar to that already described, with minor differences between the different cell types. An intense activity of the Golgi system was found associated with the thick external cell wall, with large dictyosomes from which numerous vesicles and cisternae are released. An interesting type of cisternae was found in the cryofixed material, which was not visible with the chemical fixation. These are elongated structures, in sections appearing tubule-like, close to the external cell wall or to young internal walls. An increased number of these structures was observed near the plasmodesmata of the pit fields. They are similar to the “flat cisternae” found associated with the forming cytokinetic diaphragm of brown algae. Their possible role is discussed. The new findings of this work underline the importance of such combined studies which reveal new data not known until now using the old conventional methods. The main conclusion of the present study is that cryofixation is the method of choice for studying Laminaria cytology by transmission electron microscopy.

中文翻译：

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通过结合常规化学固定和冷冻固定对海带超微结构的新见解

本研究的目的是使用化学固定和冷冻固定检查海带营养细胞的精细结构。选择海带是因为它在广泛的生物学研究中作为模式生物的重要性，作为北大西洋岩石海岸的关键物种，它使用碘化物作为独特的无机抗氧化剂，以及它作为原材料的重要性藻酸盐的生产。描述了营养细胞的精细结构特征的细节，特别强调了所使用的两种方法之间的差异，即常规化学固定和冷冻固定。细胞的一般结构与已经描述的相似，不同细胞类型之间存在细微差别。高尔基体系统的强烈活动被发现与厚厚的外细胞壁有关，具有大的双核糖体，从中释放出许多囊泡和池。在冷冻固定的材料中发现了一种有趣的水池，化学固定是看不到的。这些是细长的结构，部分呈小管状，靠近细胞外壁或年轻的内壁。在坑场的胞间连丝附近观察到越来越多的这些结构。它们类似于与褐藻形成细胞质隔膜相关的“扁平水池”。讨论了它们可能的作用。这项工作的新发现强调了这种联合研究的重要性，这些研究使用旧的传统方法揭示了迄今为止未知的新数据。