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

The role of ions in the generation and mechanism of propagation of variation potential (VP) has been widely investigated. It is likely that Ca(2+) influx via calcium channels is an initial stage of VP; however, development of long-term 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.