THE INFLUENCE OF GROWTH REGULATORS ON DAHLIA PROPAGATION IN TISSUE CULTURE AND ACCLIMATIZATION OF PLANTS IN ex vitro CONDITIONS

Abstract

The aim of work was to evaluate the influence of cytokinins on dahlia propagated in vitro and their consequent effect on acclimatization. Plant material were shoot tips and nodes. From three cytokinins, benzyladenine, kinetin and 2-isopentenyl-adenine, only BA effectively stimulated shoot multiplication from axiliary buds. The highest multiplication rate was obtained from nodes in presence of 0.25–0.5 mg·dm–3 BA. Higher concentrations shortened internodes and decreased leaf blades and growth of callus. 1 mg·dm–3 of KIN and 2iP positively influenced shoots growth and size of leaves. Gibberellic acid (GA3) used with BA increased the number of axillary shoots. The best quality shoots and the highest multiplication rate were obtained when 2 mg·dm–3 BA was used with 5 mg·dm–3 GA3. Cytokinins affected rooting and acclimatization ex vitro. Dahlias shoots multiplicated in presence of 1 mg·dm–3 KIN or 2iP rooted faster in the soil and 100% survived in field, while those from 1 mg·dm–3 BA media rooted slowly, had shorter shoots and only 60% survived. Plants bloomed after 11–12 weeks in the field. Dahlia plants that had been multiplicated in presence of KIN had a bigger diameter and fresh weight in the field. BA and 2iP positively influenced flowers diameter, length of flower stalk and a number of first order shoots.