XVI International Botanical Congess

An unfamiliar class of electrical events with rapid rise and slow decay has been identified in plants impaled by metal electrodes. Rise-times of these extracellularly recorded events can be 200 ?s or less while fall times can require hundreds of milliseconds, and they have been detected in a variety of herbaceous plants. The hypothesized origin of these events is the fracture of water columns in the xylem and the riboelectrification which occurs as the ends of the columns snap apart to form emboli. In excised tomato shoots, these events are strongly associated with the imposition of sudden water stress, and their temporal occurrence follows a pattern consistent with nocturnal healing of the emboli.