科研之友
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摘要
An improved method of direct somatic embryogenesis (SE) was developed in Swertia chirata for the first time using leaves and roots of in vitro-grown young seedlings. In the present study, 2,4-dichlorophenoxyacetic acid (2,4-D) was assessed individually and in combination with other auxins, as well as with cytokinin for its effectiveness to induce somatic embryos. Leaf explants with abaxial side in the medium produced maximum number of somatic embryos. This system omits the callus stage and thus reduces the process of SE in S. chirata by 35-45 days. Embryos at different stages of development were observed. Maturation of heart stage embryos were observed on Murashige and Skoog (MS) medium containing 1 mg L(-1) 2,4-D. Upon transfer to the germination medium, they were converted to cotyledonary stage and then plantlets of 33% and 68% of them were converted to cotyledonary stage and then plantlets on MS medium supplemented with 0.05 and 0.1 mg L(-1) GA(3) respectively. The 2,4-D alone at 1.0 or 1.5 mg L(-1) was found to be better for embryogenic tissue initiation than 2,4-D in combination with indole-3-acetic acid or alpha-naphthalene acetic acid. For further embryo development, 2,4-D was combined with cytokinins such as 6-benzylaminopurine (BAP) and kinetin or plant growth regulator free medium or medium with 50% reduced concentration of the same hormone while subculturing. Mean germination and percentage of survival were maximum in the medium containing 1.0 mg L(-1) 2,4-D in combination with 0.1 mg L(-1) BAP. Regenerated plantlets were morphologically and genetically identical. This method offers a vast scope for the clonal propagation of endangered plants.
- 出版日期2011-7
