CYTOPLASMIC FREE CALCIUM IN RICCIA-FLUITANS L AND ZEA-MAYS-L - INTERACTION OF CA-2+ AND PH
CYTOPLASMIC FREE CALCIUM IN RICCIA-FLUITANS L AND ZEA-MAYS-L - INTERACTION OF CA-2+ AND PH
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DOI：
10.1007/bf00392452
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发表时间：
1988-11-01
期刊：
影响因子：
4.3
通讯作者：
FELLE, H
中科院分区：
文献类型：
--
作者：
FELLE, H
用双管微电极测定了玉米（根毛、胚芽）和蓖麻（根状体、菌体）细胞内Ca2+和pH值。109 ~ 187 nM（蓖麻根）、94 ~ 160 nM（蓖麻体）、145 ~ 231 nM（玉米根毛）、84 ~ 143 nM（玉米胚芽）的游离Ca2+活性被鉴定为细胞质。在少数情况下（Riccia rhizzoids），游离Ca2+在较低的毫摩尔范围内（2.3 .+-）。0.8毫米)。外部Ca2+从0.1到10 mM的变化引起细胞质游离Ca2+的初始和短暂的增加，最终稳定在低于对照的0.2 pCa单位，而在氰化物存在下，Ca2+活性恢复到对照水平。这表明，这种行为是活跃的细胞Ca2+调节的指示，因为它是能量依赖的，可能涉及Ca2+- atp酶。细胞质pH的酸化和液泡pH的碱化导致细胞质游离Ca2+同时增加，而pH的碱化降低了Ca2+活性。由于这对于像蓖麻和玉米这样的远程生物来说是正确的，因此可以得出结论，细胞质pH和游离Ca2+的调节是相互关联的。进一步得出结论，双管微电极是研究植物细胞内离子活性的有效工具。
In cells of Zea mays (root hairs, coleoptiles) and Riccia fluitans (rhizoids, thalli) intracellular Ca2+ and pH have been measured with double-barrelled microelectrodes. Free Ca2+ activities of 109-187 nM (Riccia rhizoids), 94-160 nM (Riccia thalli), 145-231 nM (Zea root hairs), 84-143 nM (Zea coleoptiles) were found, and therefore identified as cytoplasmic. In a few cases (Riccia rhizoids), free Ca2+ was in the lower millimolar range (2.3 .+-. 0.8 mM). A change in external Ca2+ from 0.1 to 10 mM caused an initial and short transient increase in cytoplasmic free Ca2+ which finally levelled off at about 0.2 pCa unit below the control, whereas in the presence of cyanide the Ca2+ activity returned to the control level. It is suggested that this behaviour is indicative of active cellular Ca2+ regulation, and since it is energy-dependent, may involve a Ca2+-ATPase. Acidification of the cytoplasmic pH and alkalinization of the vacuolar pH lead to a simultaneous increase in cytoplasmic free Ca2+, while alkalinization of pHc decreased the Ca2+ activity. Since this is true for such remote organisms as Riccia and Zea, it may be concluded that regulation of cytoplasmic pH and free Ca2+ are interrelated. It is further concluded that double-barrelled microelectrodes are useful tools for investigations of intracellular ion activities in plant cells.