Acta Univ Latv (2004) 676: 239–242

The influence of thidiazuron on shoot regeneration and proliferation of rhododendrons in vitro

Abstract

To improve shoot regeneration and proliferation methods for Rhododendron L., the present study was initiated to test the effect of thidiazuron (TDZ) on (i) adventitious shoot regeneration from flower explants (each consisting of an ovary with pedicel) and (ii) shoot proliferation. For regeneration, flower explants of evergreen rhododendron cv. 'Irina' were placed on Andersonʼs medium supplemented with various combinations of TDZ (0 - 2 mg l-1), N6-Δ2-isopentenyl adenine (15 mgl-1) and indole-3-butyric acid (3 mg l-1). For proliferation two-node microshoot cuttings were placed on Anderson's medium supplemented with various concentrations of TDZ (0 - 2 mg l-1). Application of TDZ induced direct adventitious shoot regeneration from flower explants. Concentrations of 0.05 to 1 mg l-1 TDZ were found to be efficient. A higher TDZ concentration irreversible suppressed shoot elongation. As TDZ treatment inhibited further development of axillary buds, it could not be used for promotion of rhododendrons shoot proliferation in vitro.