Organogenesis in vitro of tissues from mature conifers

Summary Shoot and embryolike structures were obtained in cultures of various tissues of mature conifer trees. Morphogenesis occurred in haploid and diploid tissues of female cones ofPinus mugo andPicea abies, although only rarely. Vegetative shoots dissected from early spring buds ofAbies balsamea, Picea glauca, andPseudotsuga menziesii were more responsive, with most of the organized growth occurring at the base of young needles. The following sequence of treatments was most effective: (a) collect twigs with buds shortly before budbreak, (b) cold store for at least 1 month, (c) force buds to break before excision of the vegetative shoots (keep submerged in water during excision), and (d) soak explant in malonic acid, 1 g/l, for 15 min before transfer of the shoots to the nutrient medium.