Plant Regeneration through Somatic Embryo in Herpetospermum pedunculosum,an Endangered Tibetan Medicinal Herb / 中草药·英文版

ABSTRACT

Objective An effective reproducible protocol for complete plant regeneration via somatic embryogenesis has beendeveloped for Herpetospermum pedunculosum,an endangered Tibetan medicinal herb.Methods The cotyledonexplants used in this study were excised from seedlings germinated in vitro.Callus was induced from cotyledonexplants on Murashige and Skoog's medium,supplemented with 2,4-dichlorophenoxyacetic acid(2,4-D,0.1-1.0mg/L)alone or in combination with 6-benzylaminopurine(BA,0.5,1.0,and 2.0 mg/L).Results The calli showeddifferentiation of globular embryos after three weeks of incubation on MS medium supplemented with variouscombinations of BA and NAA.Sixty-two percent of the embryogenic calli produced somatic embryos in MS basalmedium supplemented with BA(1.0 mg/L)+NAA(2.0 mg/L).The addition of KN(0.5 mg/L)to MS mediumcontaining both BA and NAA(2.0 mg/L each)significantly increased the frequency of somatic embryogenesis.Themaximum percentage of embryogenic calli formation was 83%,and globular embryos formed and germinatedsuccessfully in this medium.Then,transferring the regenerated plants from this medium to hormone-free MSmedium will further enhanced the development of the plants,and the healthy plantlets are formed successfullywithin four weeks.The plantlets were transferred to soil to acclimatize under greenhouse conditions and 75%survived.Conclusion Somatic embryogenesis protocol as reported here can play a key role in the propagation andconservation of this endangered species.