In vitro adventitious shoot formation on cotyledons of Pinus pinea

Plant regeneration was obtained from adventitious buds induced in isolated cotyledons of Italian stone pine (Pinus pinea L.). The best results for bud induction were obtained by using half-strength LePoivre medium with 4.5 mu M 6-benzyladenine for 30 days. Shoot elongation was achieved in the same medium without growth regulators but with the addition of 0.5 % activated charcoal. The induction medium was the best also for shoot multiplication, but it was necessary to include subcultures on elongation medium. The slow elongation rate of adventitious shoots remains the greatest obstacle to multiplication. Root formation (15%) after 5 months was observed when shoots were cultured on elongation medium for long periods.