Prereservation of a rare bog pine genotypes using micropropagation techniques

Abstract

Bog pine (Pinus uncinata DC. subsp. uliginosa (Neumann) Businský) is a subendemic species and appears to be one of the most endangered tree species of the Czech Republic. Its rare populations are at the present time greatly endangered namely by spontaneous hybridization with the Scots pine (Pinus sylvestris L.). Regarding the fact that its protection is insufficient even in national nature reserves (NNR) and the classical propagation by cuttings is problematic, modern methods were adopted for a long-term preservation of the taxon. Growth regulation conditions were investigated for the induction of organogenesis and somatic embryogenesis. Mature seeds were obtained from selected trees in the Žofinka NNR and from a locality near the village of Krajková in the Sokolov district. Cotyledon and hypocotyl segments from seedlings pregerminated in sterile conditions were used to induce the organogenesis. Bud proliferation was observed on the cotyledons after 4 weeks. The largest amount of buds was found on the medium with 1.5 mg . l−1 benzyladenine (BA) and 0.5 mg . l−1 1-naphtylacetic acid (NAA) after 12 weeks. The hypocotyl segments showed only the formation of green callus. Isolated mature zygotic embryos were used for the induction of somatic embryogenesis. Development of mucilaginous callus was recorded after 3 weeks of cultivation on media with different combinations of BA, NAA and 2,4-dichlorophenoxy acetic acid (2,4-D) concentrations. When the callus induced on the medium with the combination of 0.56 (1.13) mg . l−1 BA and 1.86 mg.l−1 NAA was transferred on the medium with lower BA (0.113 mg . l−1) and 2,4-D (0.44 mg.l−1) concentrations, the first somatic embryos started to emerge after a period of other two weeks.

Keywords

• <i>Pinus uncinata</i> subsp. <i>uliginosa</i>
• seeds
• <i>in vitro</i> germination
• organogenesis
• somatic embryogenesis