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Controls on calcium ion fluxes in injured or shocked corn root cells: Importance of proton pumping and cell membrane potential
Author(s) -
Rincon Magaly,
Hanson John B.
Publication year - 1986
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1986.tb05058.x
Subject(s) - fusicoccin , depolarization , biophysics , verapamil , calcium , membrane potential , chemistry , membrane , biochemistry , biology , atpase , organic chemistry , enzyme
Passive influx of 45 Ca 2+ into non‐growing corn root tissue ( Zea mays L.) was increased as a result of actions (cutting, rubbing, chilling, heating, acidifying) or agents (cyanide, uncouplers) known to depolarize the cell membrane, and was decreased by actions (washing) or agents (fusicoccin) known to hyperpolarize it. These responses indicate the presence of Ca 2+ channels which are voltage controlled. If the injuries were extensive, however, voltage control was lost and hyperpolarization with fusicoccin was expressed by increased 45 Ca 2+ influx. Control could be regained by tissue washing, and millimolar levels of external Ca 2+ would protect against loss of control. Influx of Ca 2+ was strongly inhibited by La 3+ , but only weakly by verapamil. Intact roots showed greater cold shock sensitivity in maturing cells than in growing cells. We conclude that corn roots normally restrict Ca 2+ influx by a mechanism linked to hyper‐polarization of the plasmalemma. Calcium ions which enter cold‐shocked tissue are partially extruded during the early phase of recovery by a process stimulated by fusicoccin and subject to uncoupling.