THE INFLUENCE OF GROWTH RETARDANTS AND BA ON THE GROWTH AND DEVELOPMENT OF TIBOUCHINA URVILLEANA COGN. IN VITRO

This study was conducted to investigate the effect of different growth regulators on the growth, branching and rooting of Tibouchina urvilleana shoots in vitro. Shoot tips isolated from in vitro grown shoots were cultured on Murashige and Skoog (MS) medium supplemented with growth retardants (paclobutrazol – 0.1; 0.5; 1; 5 mg L^-1, flurprimidol – 0.1; 1; 5 mg L^-1, CCC – 5; 50 mg L^-1) and benzyladenine – 1; 5 mg L^-1. It was found that paclobutrazol, flurprimidol and BA significantly suppressed the growth of the main shoot. The reduction of length was greatest on the medium supplemented with paclobutrazol 5 mg L^-1, and in the presence of 5 mg L^-1 flurprimidol. Application of 5 mg L^-1 BA stimulated axillary shoot development the most. All retardants significantly promoted rhizogenesis. Root number was the largest on the medium with 5 mg L^-1 flurprimidol, but swelling of the roots was observed in this treatment. Root elongation was inhibited by all studied growth regulators.