Propagation of Ornamental Plants
9(2): 71-77, 2009
IN VITRO REGENERATION OF SOPHORA JAPONICA l. 'PENDULA' FROM COTYLEDON EXPLANTS VIA SOMATIC EMBRYOGENESIS AND ADVENTITIOUS SHOOT INDUCTION
Xiao-yan Cao1, Zhe-zhi Wang1*, and Niu Dong2
1 Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Development of Endangered Crude Drugs in Northwest of China, Shaanxi Normal University, Xi'an 710062, China, *Fax: + 8629 8531 0546, *E-mail: zzwang@snnu.edu.cn 2 USDA/ARS/WRRC/CIU, 800 Buchanan St., Albany, CA 94710, USA
Abstract
In vitro plant regeneration from cotyledon explants of Sophora japonica L. 'Pendula' has been achieved via somatic embryogenesis and adventitious shoot induction. The results indicated that somatic embryogenesis was determined by 2,4-D or NAA and adventitious shoot induction was determined by BA. The induction rates of somatic embryos were significantly influenced by the concentration of auxin, explant maturity and the orientation of the explants on the medium. Through the induction rates of somatic embryos could reach 100% when the juvenile cotyledons were cultured abaxial surface down on the MS medium supplemented with 10-40 mg l-1 2,4-D or 20 mg l-1 NAA, MS medium supplemented with 30 mg l-1 2,4-D was the optimal medium for the somatic embryo induction because globular embryos were first seen on this medium and cotyledon explants were covered with highest quantity of embryos. Somatic embryos developed further on MS medium supplemented with 5 g l-1 active charcoal and then germinated into plantlets on hormone-free MS medium. The germination rate of somatic embryos to plantlets was only 8% on hormone free MS medium but could increase to 21% when the somatic embryos were treated with physical dessication for 1 week. The application of BA as the sole growth regulator was effective in inducing adventitious shoot formation. Cotyledons cultured on MS medium containing 5 mg l-1 BA produced the highest frequency of shoot formation (65.2%) after 2 months of culture.
Key words: organogenesis, plant regeneration, somatic embryogenesis, Sophora japonica L. 'Pendula'
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