The apoplastic pH and its significance in adaptation to salinity in maize (Zea mays L.): Comparison of fluorescence microscopy and pH-sensitive microelectrodes.
The apoplastic pH and its significance in adaptation to salinity in maize (Zea mays L.): Comparison of fluorescence microscopy and pH-sensitive microelectrodes.
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DOI：
10.1016/j.plantsci.2009.01.002
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发表时间：
2009-04
期刊：
影响因子：
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通讯作者：
B. Pitann;T. Kranz;Karl H. Mühling
中科院分区：
文献类型：
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作者：
B. Pitann;T. Kranz;Karl H. Mühling
质外体离子环境包含细胞扩张和植物生长的重要决定因素。由于 pH 值是细胞外空间的多功能基本组成部分，因此了解其在应激情况下的行为至关重要。在玉米（Zea mays L. cvs. Pioneer 3906 和 SR 03）的分离叶子中，测量盐度对质外体 pH 值的影响，以研究其对盐胁迫的适应作用，采用两种不同的方法：使用 pH 敏感荧光染料（异硫氰酸荧光素-葡聚糖 (FITC)、荧光素四甲基罗丹明-葡聚糖 (FTMR) 和俄勒冈的光学方法） Green®488），以及电生理学技术、pH 敏感微电极。两种方法都产生了相似的结果。在生长培养基中添加 100mM NaCl 的情况下，盐敏感玉米基因型 Pioneer 3906 叶片的质外体 pH 最大增加 0.4 个单位（pH 微电极）和 0.3 个单位（荧光染料）；耐盐的 SR 03 几乎没有反应。同样的处理使 Pioneer 3906 的叶片生长减少了 60%，但在 SR 03 中仅减少了 40%。由于根据酸生长考虑，质外体 pH 值是伸长生长的重要因素，因此我们认为 pH 值的增加是盐胁迫条件下叶片生长减少的主要原因。
The apoplastic ionic milieu contains essential determinants for cell expansion and plant growth. Since pH is a multifunctional basic component of this extracellular space, the knowledge of its behaviour during stress situations is of major importance. In detached leaves of maize (Zea mays L. cvs. Pioneer 3906 and SR 03) the effect of salinity on apoplastic pH was measured to investigate its adaptive role to salt stress applying two different methods: an optical approach using pH-sensitive fluorescent dyes (fluorescein isothiocyanate-dextran (FITC), fluorescein tetramethylrhodamine-dextran (FTMR) and Oregon Green®488), and an electrophysiological technique, pH-sensitive microelectrodes. Both approaches yielded similar results. In the presence of 100mM NaCl, which was added to the growth medium, apoplastic pH of the salt-sensitive maize genotype Pioneer 3906 leaves increased in maximum by 0.4 units (pH microelectrodes) and by 0.3 units (fluorescent dyes); the salt-resistant SR 03 hardly responded. The same treatment reduced leaf growth by 60% in Pioneer 3906, but only by 40% in SR 03. Since according to acid growth considerations apoplastic pH is an important factor in elongation growth, we suggest that this pH increase is a main cause for reduced leaf growth under salt stress conditions.