A comparison of nitrate-selective microelectrodes made with different nitrate sensors and the measurement of intracellular nitrate activities in cells of excised barley roots
A comparison of nitrate-selective microelectrodes made with different nitrate sensors and the measurement of intracellular nitrate activities in cells of excised barley roots
复制标题
不同硝酸盐传感器制作的硝酸盐选择性微电极的比较以及离体大麦根细胞内硝酸盐活性的测量
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
A. Miller
中科院分区：
文献类型：
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作者：
R. Zhen;Susan J. Smith;A. Miller
摘要对基于多种硝酸盐传感器的硝酸盐选择微电极进行了比较。所测试的电极性能包括校准曲线的对数线性斜率、检测下限和离子选择性。与其他硝酸盐选择性混合物或市售大分子电极相比，前文中描述的硝酸盐传感器混合物表现良好。该早期混合物由6%的甲基十三烷基硝酸铵、65%的w-苯基叔醚、23%的聚氯乙烯、5%的硝化纤维和1%的甲基三苯基溴化铵组成。这些电极，即使在储存回填的情况下，在几天内仍然对硝酸盐具有选择性，尽管最终性能会有所下降。这些电极被用于体外测定大麦根提取物中的硝酸盐，离子色谱和微电极测量的结果之间存在线性关系。在活体大麦根的表皮细胞中进行的细胞内测量发现了两组被认为是细胞质和液泡的测量结果。切除后2~6h，脑室内硝酸盐活性显著降低。这些结果表明，根表皮细胞的细胞质和液泡中的硝酸盐池对根切除很敏感，并质疑对切除的根进行测量的生理意义。关键词：硝酸盐选择微电极，大麦根，区划，硝酸盐。
ABSTRACT Nitrate-selective microelectrodes based on a number of nitrate sensors were compared. The electrode properties tested includedlog-linear slope of the calibration curves, detection limit, and ion selectivity. The nitrate sensor mixture described in an earlierpaper performed favourably when compared with other nitrate-selective mixtures or with commercially-available macroelectrodes.This earlier mixture consisted of 6% methyltridodecylammonium nitrate, 65% w-phenyloctyl ether, 23% poly(vinylchloride), 5%nitrocellulose, and 1% methyltriphenyl phosphonium bromide. These electrodes, even when stored backfilled remained nitrate-selective for several days although there was eventually some deterioration in performance.The electrodes were used in vitro for assaying nitrate in barley root extracts and a linear relationship was found between resultsfrom ion chromatography and microelectrode measurements. Intracellular measurements made in vivo in epidermal cells of excisedbarley roots identified two populations of measurements believed to be the cytoplasm and the vacuole. Significant decreases incompartmental nitrate activities were measured 2 to 6 h after excision. These results indicate that the nitrate pool in both thecytoplasm and vacuole of root epidermal cells is sensitive to root excision and question the physiological significance ofmeasurements made on excised roots.Key words: Nitrate-selective microelectrodes, barley root, compartmentation, nitrate.