Electric Characteristics and Cytoplasmic Streaming of Characeae Cells Lacking Tonoplast
Electric Characteristics and Cytoplasmic Streaming of Characeae Cells Lacking Tonoplast
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缺少液泡膜的山藻科细胞的电特性和细胞质流
DOI：
10.1247/csf.1.165
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发表时间：
1976
影响因子：
1.5
通讯作者：
T. Shimmen
中科院分区：
文献类型：
--
作者：
M. Tazawa;M. Kikuyama;T. Shimmen
用含有Ca2+螯合剂EGTA[乙二醇-双-（β-氨基乙醚）N， N'-四乙酸]的溶液代替细胞液，去除性状节间的细胞质。置换后，液泡内可见小的内质颗粒和内质滴状物，轮廓不清晰。这些观察证实了舌质体的消失。内质滴中的叶绿体常发生旋转。保留在皮质凝胶上的内质以与正常细胞细胞质流中的内质几乎相同的速度活跃地流动至少几个小时。在无张力质体细胞中，ATP和Mg2+对细胞质流动是必不可少的。无张力细胞具有很高的膜抗性。电流-电压关系表明，去除膜质体后，膜的整流作用增强。细胞的动作电位呈矩形延长。虽然在正常细胞中普遍存在，但在无张力细胞中从未观察到伴随动作电位的细胞质流动的停止。当灌注介质中游离Ca2+浓度小于10-6 m时，这些现象才会在无张力质体细胞中发生。通过分析原生质中的钙浓度来估计张力质体解体后细胞内游离Ca2+浓度，并将细胞质结合的Ca分散到整个细胞空间。
The tonoplast of Characeae internode was removed by replacing the cell sap with solution containing a Ca2+-chelating agent EGTA [Cethyleneglycol-bis-(β-aminoethyl ether) N, N'-tetraacetic acid]. After replacement, small endoplasmic granules and endoplasmic drops without clear outline were observed in the vacuole. These observations confirmed the disappearance of the tonoplast. Chloroplasts in the endoplasmic drop were often observed to rotate. The endoplasm remaining on the cortical gel flowed actively at nearly the same rate as endoplasm in cytoplasmic streaming of normal cells for at least several hours. ATP and Mg2+ were indispensable for cytoplasmic streaming in tonoplast-free cells. The tonoplast-free cells had very high membrane resistance. The current-voltage relationship showed that the membrane rectifying action was strengthened by removing the tonoplast. The cells elicited prolonged action potentials of rectangular shape. Cessation of cytoplasmic streaming accompanied with the action potential was never observed in tonoplast-free cells although this is generally observed in normal cells. These phenomena on tonoplast-free cells occurred only when the concentration of free Ca2+ in the perfusion medium was less than 10-6 M. The calcium concentration in the protoplasm was analyzed to estimate the free Ca2+ concentration in the cell after disintegration of the tonoplast and dispersion of the cytoplasm-bound Ca into the entire cell space.