Calcium in gravitropism. A re-examination
Calcium in gravitropism. A re-examination
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DOI：
10.1007/pl00008120
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发表时间：
1997-01-01
期刊：
影响因子：
4.3
通讯作者：
Trewavas, AJ
中科院分区：
文献类型：
--
作者：
Sinclair, W;Trewavas, AJ
十多年来，人们一直认为Ca 2+和向重力性之间存在很强的关系。有证据表明，细胞壁中Ca ~（2+）的运动可能调节伸展生长，细胞内游离Ca ~（2+）可能介导平衡细胞中的信号传导。然而，细胞壁Ca ~（2+）或细胞内游离钙浓度[Ca ~（2+）]（i）的变化不太可能相互独立地起作用。这导致在实验和实验信息的解释的歧义。同样不确定的是，所观察到的细胞壁Ca 2+的重新分布是否足以诱导弯曲，并且目前没有来自测量或成像的直接证据表明[Ca 2 +]（i）的变化启动或消除向重力信号。因此，有关钙离子与向重力性的证据是大量的，但仍然是间接的。细胞内游离Ca 2+的参与可能是最好的测试使用新技术的转基因水母发光蛋白靶向柱细胞，从而解决这个重要的问题。新的信息，涉及控制或取向的尖端生长的细胞，如花粉管，胞质Ca 2+操纵。这一信息可能直接适用于一个向重力性模式系统研究了多年，轮藻假根。
For more than a decade it has been assumed that there is a strong relationship between Ca2+ and gravitropism. There is evidence to suggest that the movement of Ca2+ in the wall might regulate extension growth and that free intracellular Ca2+ might mediate signalling in statocytes. However, it is unlikely that changes-in either wall Ca2+ or the concentration of free intracellular calcium, [Ca2+](i), act independently of each other. This results in ambiguity in both experimentation and interpretation of experimental information. It is also uncertain that the observed redistributions of wall Ca2+ are sufficient to induce bending and there is at present no direct evidence from measurement or imaging that changes in [Ca2+](i) initiate or transduce gravitropic signals. The evidence relating Ca2+ to gravitropism is therefore substantial but still circumstantial. The involvement of free intracellular Ca2+ might best be tested using the new technologies of transgenic aequorin targeted to columella cells and thus resolve this important question. New information which relates control or orientation of tip-growing cells, such as pollen tubes, to cytosolic Ca2+ manipulation is presented. This information may be directly applicable to a gravitropic model system studied for many years, the Chara rhizoid.