High-frequency Induction of Adventitious Shoots from Leaves of Robinia pseudoacacia by Thidiazuron

The effectiveness of thidiazuron (TDZ) on adventitious bud and shoot formation from leaves of Robinia pseudoacacia was tested in combination with naphthaleneacetic acid (NAA) or 2, 4- dichlorophenoxyacetic acid (2, 4-D). With the increasing of TDZ level, the induction rate of adventitious buds appeared an increasing trend and the highest rate was obtained by the combination of 2 mg/L TDZ with 0.1 mg/L NAA.The excessive level of TDZ could induce useless cellae and easily produce hyperhydricity. Inhibition of shoot elongation by TDZ was overcome through transferring shoot cultures to a shoot proliferation medium lacking TDZ or containing NAA, benzyladenine (BA) and TDZ. Indole- 3-butyric acid (IBA) was used to stimulate the rooting in vitro. Based on the number and length of rooting, the treatment with 0.5 mg/L IBA was the best.