Pitman M G, Läuchli A, Stelzer R
Botanisches Institut, Tierärztliche Hochschule Hannover, D-3000 Hannover 71, Federal Republic of Germany.
Plant Physiol. 1981 Sep;68(3):673-9. doi: 10.1104/pp.68.3.673.
The distribution of ions, particularly K and Na, was studied in roots of barley seedlings grown on various ionic solutions. Analyses were made by means of electron probe x-ray microanalysis using frozen, fractured bulk specimens. By this technique, it was demonstrated that there can be variability in the ratio K/Na measured in the vacuoles of cortical cells, with this ratio often being lower in epidermal cells of the root than in the inner cortex. A sharp difference in the K/Na ratio was also found between cells of the endodermis and those of the adjacent cortex, and generally higher ratios of K/Na occurred in the stele than in the cortex. Estimation of the concentrations in the cytoplasm was at the limit of resolution of this technique, but it can be shown that the K/Na ratio in the cytoplasm was higher than that in the vacuole. In low salt roots, the K concentration in the cytoplasm was higher than that in the vacuoles. The results with the x-ray microprobe confirm other measurements based on flux analysis or analysis of small samples of the root.
研究了在各种离子溶液中生长的大麦幼苗根系中离子的分布情况，尤其是钾离子和钠离子。采用电子探针X射线微分析法，对冷冻、断裂的大块标本进行分析。通过该技术表明，皮层细胞液泡中测得的钾/钠比值存在变异性，根部表皮细胞中的该比值通常低于内皮层。在内皮层细胞与相邻皮层细胞之间也发现了钾/钠比值的显著差异，一般来说，中柱中的钾/钠比值高于皮层。对细胞质中浓度的估计处于该技术分辨率的极限，但可以表明细胞质中的钾/钠比值高于液泡中的比值。在低盐根系中，细胞质中的钾浓度高于液泡中的钾浓度。X射线微探针的结果证实了基于通量分析或根系小样本分析的其他测量结果。
