Mother plant age and seasonal influence on in vitro propagation of Quercus euboica Pap., an endemic, rare and endangered oak species of Greece

A micropropagation method for Quercus euboica Pap. was developed. Nodal explants from seedlings gave higher multiplication rates than explants from adult plants. Cultures initiated at the beginning of May produced the highest percentage of shoot forming explants and multiplication rate. Woody Plant Medium (WPM) salts, with 100 mg l(-1) myoinositol, 1 mg l(-1) thiamine, 0.5 mg l(-1) pyridoxine, 0.5 mg l(-1) nicotinic acid and 3% sucrose was used as basal medium and several cytokinins at various concentrations were evaluated for their effect on shoot multiplication. The highest shoot multiplication rate was obtained with 4.44 mu M BA. IBA at 9.84 mu M in the culture medium during the first week of culture, and if followed by culture in hormone-free medium, gave the best rooting results. Darkness at the beginning of the rooting period did not improve rooting. The use of plastic wrap as a cover material of the culture vessels enhanced rooting percentage and root number. Plantlets acclimatized ex vitro in soil from the natural environment of the species survived at a higher percentage (up to 93%) and had more vigorous growth than plantlets grown in a compost-perlite (2:1 v/v) medium (up to 36%).