Finally, for the effect of the NAA and IBA on cell growth and inductive rate, the ratio of NAA to IBA was varied in the
basal medium. The results showed that the optimum culture medium of root formation on shoots and plantlets induced
from the rhizome callus was the medium containing NAA 0.2–0.5 mg/l and IBA 0.5 mg/l. Further investigation on the
ratio of NAA to IBA showed that when IBA was added into the single auxin of different concentrations, inductive rates
of root formation were different (Table 6).