Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: "propagation of several Betula species representing various ploidy levels. | 152s Ann. Sci. For. 1989 46 suppl. 152s-154s Forest Tree Physiology E. Dreyer et al. eds. Elsevier INRA In vitro propagation of several Betula species representing various ploidy levels E. Sãrkilahti Department of Biology University of Turku SF-20500 Turku Finland Introduction One of the most important applications of in vitro culture is micropropagation which enables vegetative propagation of adult trees not usually achieved with traditional methods. Genotypic variability in response to successful in vitro propagation within a species has been a difficulty in finding universal propagation methods for some species. This paper introduces the establishment of sterile shoot culture and micropropagation of 4 different mature birch species having tetrapioid and penta-ploid chromosome sets. The effect of a lanolin layer on relative humidity RH in a culture vessel as well as on shoot growth and multiplication was studied to improve survival in a greenhouse. Materials and Methods In vitro cultures were initiated from dormant apical and axillary buds of 6 birch genotypes representing different species and ploidy levels Table I . Cultures were grown on MS medium Mura-shige and Skoog 1962 having a modified macromineral composition Simola 1985 supplemented with mg l benzylaminopurine BAP mg l a-naphthalene acetic acid NAA and casein hydrolysate CH under growth conditions described in detail by Sãrki-lahti 1988 . The same medium was used for Table I. Betula genotypes cultured in vitro. Species Ploidy 2n Genotype origin B. pubescens ssp. tortuosa 4x 56 mountain birch B. pendula 4x 56 colchicine-tetraploid and irradiation-mutant n 4x 56 colchicine-tetraploid B. papyrifera var. subcordata 4x 56 colchicine-treated normal var. papyrifera 5x 70 B. pubescens ssp. tortuosa 5x 70 mountain birch hybrid 153s both induction of adventitious buds and culture of new shoots. Rooting medium had the same composition but with mg l NAA as the sole growth regulator. Rooted plantlets .
