THE SELF-OSCILLATIVE NATURE OF WATER PUMPING BY ROOT-SYSTEM OF ZEA-MAYS-L

The experiment was conducted with roots of 6-8-day-old corn seedlings. The effect of the following chemical agents on the period and amplitude of auto-oscillations of water absorption and xylem juice exudation was studied: CaC12, DNP, carbonyl cyanide-3-chlorphenyl hydrazone, cytochalasin B, colchicine, pipolphen, Na parachloromercuribenzoate, and abscisic acid. Under the effect the chemical agents auto-oscillations gradually damped: their amplitude decreased and the period increased. Only CaC12 increased their amplitude. Water transport in the root consisted of the following successive phases when the metabolic component of root pressure was functioning: relaxation phase (cells become filled with water) and contraction phase (cells force out the water into xylem vessels).