Cameron I L, Hunter K E, Smith N K
J Cell Sci. 1984 Dec;72:295-306. doi: 10.1242/jcs.72.1.295.
Quantitative electron-probe energy dispersive X-ray microanalysis has, for the first time, been accomplished at a subcellular level in plant tissue using cryofixed and thin freeze-dried cryosections. The subcellular concentrations of Na+, Cl-, K+, P, S, Mg2+ and Ca2+ were measured in mol/kg dry weight in two types of root meristematic cells of the onion, Allium cepa. The cell wall of the meristematic cells had much higher concentrations of K+ and Ca2+ than was found in the intracellular compartments. Storage granules in the protoderm cells were about 6-12 times lower in P and were about four times higher in S as compared to other intracellular compartments. Comparison between the concentrations of ions and other elements in meristematic plant cells and in mouse cardiac myocytes confirms that major differences in cytoplasmic Na+ and Cl- concentrations do indeed exist between these cell types.
首次使用冷冻固定和薄冷冻干燥的低温切片在植物组织的亚细胞水平上完成了定量电子探针能量色散X射线微分析。在洋葱（Allium cepa）的两种根分生组织细胞中，以mol/kg干重为单位测量了Na⁺、Cl⁻、K⁺、P、S、Mg²⁺和Ca²⁺的亚细胞浓度。分生组织细胞的细胞壁中K⁺和Ca²⁺的浓度比细胞内区室中的浓度高得多。与其他细胞内区室相比，原表皮细胞中的储存颗粒P含量低约6-12倍，S含量高约四倍。对分生植物细胞和小鼠心肌细胞中离子和其他元素浓度的比较证实，这些细胞类型之间细胞质中Na⁺和Cl⁻浓度确实存在主要差异。
