Abstract: The effect of etylene on the adventitious root formation has beenstudied through the experiments with Phaseolus aureus hypocotyls whichform adventitious roots easily. The study shows that ethephon and ethy-lene treatments with lower concentrations (1-5 ppm) have a stimulatingeffect or, as it were, no inhibiting effect on the adventitious root form-ation;however, their inhibiting effect becomes stronger as their concent-rations increase. IBA treatment has distinct stimulating effect on theadventitious root formation. Experiments with the incorperation of bothIBA and ethylene show that their effects seem to be independent.Therefore, it can be assumed that there exists a limit to endogenousethylene suitable for root formation, beyond which the adventitious rootformation will be inhibited.

Key words: ethlene, ethephon, IBA, phaseolus aureus hypocotyl, adventitious root