Primary bioelectric response of higher plant cells to the combined action of stress factors

Primary bioelectric responses (BER) of pumpkin (Cucurbita pepo L.) stem cel ls were induced by either an individual stress factor (gradual cooling from 20-23 to 3-4 degrees C) or a combination of several factors: 1 M KCl and c ooling (treatment 1), 10(-4) M AgNO3 and cooling (treatment 2), and burning of leaf edge by flame followed by cooling (treatment 3). Gradual cooling i nduced repetitive action potentials (AP). The number of AP in a series was comparatively high when cooling was applied after preliminary depolarizatio n of stem cells by chemicals affecting bioelectrogenesis via different mech anisms (treatments 1 and 2). On the other hand, when cooling was applied af ter burning the leaf (treatment 3), no generation of AP was detected after the propagation of variation potential along the stem. The possible role of AP as a short-term antistress response in higher plants is discussed.