Abstract: The effects of light, agar and carbon sources on the growth of in vitro cultured root tips of Fraxinus mandshurica were studied. The results showed that the growth of root tips in liquid medium was better than that in agar-solidified medium and solid-liquid two phase medium, for that increasing agar concentrations in medium will reduce the root growth; darkness was beneficial for Fraxinus mandshurica root tip culture in vitro; as the carbon sources, sucrose was better than glucose and maltose as the carbon sources, and 3% sucrose was best for the root tip growth of Fraxinus mandshurica.

Key words: Fraxinus mandshurica, root tips, vitro culture