Refining a protocol for somatic embryogenesis and plant regeneration of Phalaenopsis amabilis cv. Jinan from mature tissues

Authors: REZA GHAHREMANI, SHIRIN DIANATI DAYLAMI, MASOUD MIRMASOUMI, NASER ASKARI, KOUROSH VAHDATI

Abstract: Phalaenopsis is one of the most remarkable commercial genera in Orchidaceae family. Using immature explants for tissue culture of orchid results in undesired characteristics such as genetic variation and long-lasting juvenility. In this study, we optimized a protocol for somatic embryogenesis of Phalaenopsis amabilis cv. Jinan, by using mature thin cell layer (TCL) explants to minimize immature explant limitations. We examined somatic embryogenesis from two types of mature explants, viz. leaf lTCL and flower stalk nodes tTCL at various concentrations of thidiazuron (TDZ) (0, 1, 2, and 3 mg L^-1). The results demonstrated that lTCL explants cultured on medium supplemented with 3 mg L^-1 TDZ produced the highest number of somatic embryos (SEs) (21.5 embryos per explant), the lowest yellowish SE (7%), the highest plantlet regeneration (20.5 plantlets per explant) and the highest survival rate (94%) in comparison with tTCL explants. This protocol can be used in commercial mass propagation of Phalaenopsis to overcome the limitations such as long-term juvenility and genetic variation of plantlets regenerated in vitro by using immature explants.

Keywords: Acclimatization, mature explant, orchids, protocorm-like bodies (PLBs), thin cell layer (TCL), thidiazuron

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