Propagation of Drosera rotundifolia and Drosera capensis in an in vitro Culture System

Abstract

Drosera rotundifolia and Drosera capensis (Droseraceae) are carnivorous plants grown as ornamentals and sources for homeopathic medicine. The aim of this study was to optimize nutrient and growth regulator concentrations for the in vitro propagation of these species. Half strength MS medium (1/2MS) was supplemented with kinetin (0.5, 2, 5 mg/l) or 6-benzyladenine (3, 5 mg/l) and plantlets were transferred to 1/2MS with or without cytokinins. After 8 weeks rosette diameter, plant height, number of roots, root length were recorded and plants were cultured in full strength MS, 1/2MS or 1/2MS with 0.5 mg/l α-naphthaleneacetic acid for the same period of time. Afterwards, plant characteristics (number of roots, root length, number of shoots, number of flower stalks) were assessed. For D. rotundifolia, shoot development and rosette diameter increased significantly in the medium with 0.5 mg/l kinetin and 3 mg/l 6-benzyladenine, while root development decreased. Plant growth regulator free medium was more suitable for root development than medium with α-naphthaleneacetic acid and thus supported the formation of significantly more flower stalks. For D. capensis, kinetin was detrimental for shoot development, the optimum medium for both shoot and root formation being MS without plant growth regulators.