Abstract
Eucalyptus is a commercially valuable species for industrial plantation, mainly for pulp and paper production. However, E.globulus is difficult to vegetatively propagate. In this study, we investigated the effect of auxin on adventitious root formation of E.globulus. Indole-3-butyric acid (IBA) efficiently induced adventitious root. Adventitious root emergence and development were significantly inhibited by N-1-naphthylphalamic acid, an auxin transport inhibitor. Furthermore, we investigated the gravitropic response of E.globulus. The poor rooting lines exhibited significant decrease of gravitropic response. Theses results support the hypothesis that a polar transport of the auxin is necessary for the adventitious root formation. We examined internal concentrations of indole acetylaspartic acid (IAAsp) in the stem bases of E.globulus cuttings treated with rooting medium including IBA. After 8 days of treatment, significant increment of IAAsp was observed in high rooting lines but not in poor rooting lines. Now we are trying to isolate and characterize E.globulus GH3 genes that encode IAA-amido synthetase and the genes encoded P450 enzymes that related to auxin biosynthesis.
