THE EFFECT OF ETHYLENE ON ADVENTITIOUS ROOT-FORMATION IN MUNG BEAN (VIGNA-RADIATA) CUTTINGS

A promotive effect of ethylene on the formation of adventitious roots by mung bean cuttings was demonstrated using a recirculating solution culture system to apply dissolved ethylene. The number of roots increased in proportion to the length of exposure to the gas. Mean root numbers per cutting for a 4-day exposure to ethylene and an air control were 45 and 19, respectively. The tissue was most sensitive to a 24-h ethylene "pulse" 2-3 days after taking cuttings. Rooting was maximal at a concentration of 13 μl 1-1 ethylene. The ethylene treatment inhibited the growth of roots and terminal buds. Application of Ag+, as silver thiosulfate, reversed the effect of ethylene on the two growth responses but had no effect on root numbers. Norbornadiene, another inhibitor of ethylene action, reversed all three ethylene responses. © 1991 Springer-Verlag New York Inc.