Tissue Culture And Plant Regeneration Of Caragana Fruticosa

Caragana fruticosa (Pall.) Bess. belongs to the family of Leguminosae and is an endemic and endangered species in Heilongjiang Province with narrow distribution scope and sparse resource. C. fruticosa could be served as ornamental trees, nectar source and forage plant. In addition, it is a valuable species for vegetation rehabilitation and water conservation. The research was to establish a plant regeneration system via tissue culture of C. fruticosa. The purpose of this study was to provide an effective in vitro culture system for C. fruticosa micropropagation, germplasm resource protection and further exploitation. The results were as follows:(1)The fruit setting rate of C. fruticosa was low and 25.6% of seeds were damaged by insects; The seeds moisture content was 6.6%, the thousand-seed-weight was 18.6 g; The absorption of seeds episperm was well; The seeds with high vitality, and germination rate, however, the seeds came out unevenly.(2)The C. fruticosa leaf was easy to induce callus and the callus grew and proliferated well. But we have not got callus differentiation in the following culture.(3)The epicormics grew and elongated best but the sterile stems emitted phenolic compounds and its oxidation hampered the stems elongation, further proliferation was stopped; Plant regeneration from in vitro seedling segments was established. MS nutrient medium was superior for shoot elongation and axillary shoot proliferation. The shoots on MS medium supplemented with 0.5 mg·L-1 6-BA produced the highest proliferation coefficient (3.2). The addition of 0.05 mg·L-1 NAA on 1/2MS media was the optimal concentration for rooting (74%). Roots exhibited many stout and long root hairs. Established plantlets had an 82% survival rate 30 d after transfered to the composition of 50% peat,40% vermiculite and 10% polite.(4)Somatic embryogenesis and plant regeneration were conduced by taking immature zygotic embryos as explants. C. fruticosa somatic embryogenesis passed through pre-embryo, sphere, heart, torpedo and cotyledonary stages. The somatic embryos were originated indirectly from single cell. The inductivity of somatic embryo was low (14%),59% were germinated, with 87% of them formed into plants, and 40% plants survived in greenhouse.