Micropropagation and germplasm conservation of Central Park Splendor Chinese elm (Ulmus parvifolia Jacq. 'A/Ross Central Park') trees.
Micropropagation offers opportunities to propagate, preserve and ship tree germplasm. It also reduces the risk of moving pathogens and insects with the germplasm due to built-in pathogen detection capabilities of aseptic cultures. For the past few decades, our laboratory has been involved in a project to preserve and restore a large, cold hardy, and historically important Chinese elm (Ulmus parvifolia Jacq. 'A/Ross Central Park') tree. Here we present three simple and efficient systems for its micropropagation, germplasm conservation and distribution: (1) in vitro plant formation from meristematic nodules (MNs), (2) plantlet generation from axillary buds, and (3) in vitro rooting of micro-cuttings from 20-years-old hedged stock plants. Newly flushed nodal segments were used as explants. WPM with 0.5 mg/l BA was found to be the best medium for meristematic shoot development and WPM supplemented with 2.0 mg/l 4-CPPU and 0.5 mg/l TDZ was best for meristematic nodule formation. Rhizogenesis of regenerants and micro-cuttings was best achieved on WPM with 1.0 mg/l NAA and 2% sucrose. Rooted plants were readily acclimatized to the greenhouse ambient environment and continued to grow well under greenhouse conditions. The survival rate of acclimatized plantlets under ex vitro conditions was 100% after 4 weeks. Plants looked healthy with no visually detectable phenotypic variation based on observation of about 1,000 plants. Cycling of shoot explants and MNs through repetitive cultures was effective in scaling-up propagules.
Thakur
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RC
School of Forest Resources and Environmental Science, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA. rcthakur@mtu.edu
Karnosky
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DF
D003247:Conservation of Natural Resources / Q000379:methods*; D003470:Culture Media; D016468:Forestry / Q000379:methods; D018517:Plant Roots / Q000254:growth & development; D018520:Plant Shoots / Q000254:growth & development; D046509:Tissue Culture Techniques / Q000379:methods*; D034403:Ulmus / Q000235:genetics* / Q000502:physiology*
D003470:Culture Media