[Objective] The aim was to provide theoretical basis for speeding up the popularization of Eucalyptus dunnii.[Method] Differences in phenolic compounds and related enzyme activities between hard rooting E.dunnii and easily rooting E.urophylla×E.grandis clone （U9） were studied.[Result] There were significant differences in contents of phenolic compounds and activities of indole acetic acid oxidase （IAAO）,andperoxidase （POD） and polyphenol oxidase （PPO） between the two Eucalyptus species.Compared with U9,contents of phenolic compounds and POD activity of E.dunnii cuttings were relatively high,while activities of IAAO and PPO were relatively low.[Conclusion] More phenolic compounds and the differences in related enzyme activities might be the major factors to result in hard rooting of E.dunnii cuttings.
