Calcium and plant action potentials |
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Authors: | M J BEILBY |
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Institution: | Botany School, University of Cambridge, Downing Street, Cambridge CB2 3EA |
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Abstract: | Abstract. Under normal conditions the action potential in Characeae is dependent on the presence of both Cl? and Ca2+. Cl? seems to play a straightforward part as a transient depolarizing flow. The role of Ca2+, however, is emerging as an increasingly complex one: there are Ca2+ concentration changes in the cytoplasm, as well as transient Ca2+ currents across the plasmalemma and possibly the tonoplast. In most Characeae Ca2+ is necessary for the Cl? channel to function, and it is also involved in the cessation of the cytoplasmic streaming observed at the time of excitation. The function of Ca2+ at the time of the action potential is being revealed by experimental techniques of increasing sophistication. The development of these methods and possible associated artefacts are considered. |
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Keywords: | Chara action potentials calcium concentration cytoplasmic streaming |
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