RAPID DISTANT TRANSMISSION OF LOCAL-STRESS SIGNALS IN MAIZE SEEDLINGS

Shoots of 4-day-old etiolated maize seedlings (Zea mays L.) were expos ed to chilling temperature (4 degrees C) for 4 s. Ten minutes later, t he content of phytohormones was determined in a 10-mm apical part of t he root, 9-10 cm from the stressed region. The content of conjugates o f indoleacetic acid (IAA) in the ethanol fraction increased in treated plants by 139%, and that of abscisic acid (ABA) rose by 51% as compar ed to control plants. It was demonstrated that neither action potentia l nor variation potential propagated along the root. Hydraulic impulse s could move along root. It is hypothesized that local electrical and (or) hydraulic pulses, generated in the stressed region, can transmit a signal along the roots about a local stress imposed on a remote part of the plant.