Evaluation of the open time of calcium channels at variation potential generation in wheat leaf cells

Abstract

The role of ions in the generation and mechanism of propagation of variation potential (VP) has been widely investigated. It is likely that Ca 2C influx via calcium channels is an initial stage of VP; however, development of longterm membrane depolarization requires prolonged open times of calcium channels. We investigated depolarization time in the present study. It was shown that local burning induced VP in wheat seedling and the electrical response was suppressed under EGTA presence. Depolarization formation, which may indicate open time of calcium channels at VP generation, was observed up to 30 s after reaction induction when calcium ions were added to initially calcium-free medium. Long-term calcium channel open time may be the reason for long membrane depolarization at VP and may also be connected with the type of channels participating in wound reaction propagation.

Electrical Signals, Plant Tolerance to Actions of Stressors, and Programmed Cell Death: Is Interaction Possible?

“…The generation of long-term depolarization is related to a transient inactivation of H + -ATP-ase in the plasma membrane [ 8 , 29 , 31 , 74 , 106 ]. This inactivation is induced by a Ca 2+ influx through mechanosensitive and/or ligand-dependent calcium channels [ 8 , 31 , 34 , 35 , 107 ] (possibly GLR, MSL, and CNGC [ 19 ]), which increase the concentration of calcium ions in the cytoplasm. It is considered [ 31 ] that changes in the Cl − and K + concentrations are rather weak at the generation of long-term depolarization only (if the initial fast depolarization and/or AP-like spikes are absent).…”

High-Temperature Tolerance of Photosynthesis Can Be Linked to Local Electrical Responses in Leaves of Pea

“…VP comprises two components: a long-term depolarization and “action potential-like” spikes (Vodeneev et al, 2015 ). The long-term depolarization is connected with activation of ligand-dependent and/or mechanosensitive Ca 2+ channels and transient inactivation of H + -ATPase in the plasma membrane (Stahlberg et al, 2006 ; Fromm and Lautner, 2007 ; Gallé et al, 2015 ; Katicheva et al, 2015 ; Vodeneev et al, 2015 ); i.e., this component is similar to voltage transients and, possibly, receptor potentials. Moreover, amplitude of the long-term depolarization is dependent on stimulus strength or distance from the damaged zone (Vodeneev et al, 2011 ; Sukhov et al, 2013 ); these properties support similarity of voltage transients and, possibly, receptor potentials with the long-term depolarization.…”

O papel das nanopartículas de silício na mitigação do efeito da salinidade sobre a eletrofisiologia e na atividade fotossintética em plantas glicófitas e não acumuladora de silício

“…Através do canal iônico HKT ocorre o carregamento e descarregamento do Na + no xilema (Wu et al, 2018; O PV no tomateiro sob 100 mM (Figura 4, 5), exibiu uma dinâmica do potencial de membrana semelhante ao tomateiro e a quinoa sem estresse, evidenciado pelos valores de amplitude e duração do PV (tabela 3). Comportamento semelhante dos PVs em plantas de trigos com e sem estímulo por queima (Katicheva et al, 2015). Todavia, esse mesmo comportamento não foi observado nas plantas de quinoa, na qual em condição de salinidade essa diferença pode ser vital quanto a eficiência de resposta ao estresse, pois na fase de repolarização do PV, além do efluxo de íons de K + , também ocorre a reativação da H + -ATPase, esse processo ocorre através do bombeamento dos prótons com gasto de ATP (Sondergaard et al, 2004;Katicheva et al, 2015).…”