Effects of plant growth regulators on in vitro propagation of Cymbidium faberi Rolfe
Cymbidium faberi Rolfe is one of the oldest cultivated orchids in China, which is often sold as a precious potted specimen because of its beautiful and fragrant flowers in eastern Asia. However, the propagation of C. faberi is greatly restricted by the low seed germination rate due to immature embryo and no endosperm under natural conditions. In this study, the effects of plant growth regulators on in vitro propagation of C. faberi were investigated to establish in vitro propagation protocol. The results demonstrated that seeds began to form into white spots on 2.0 mg/L N6-benzyladenine (BA) + 1.5 mg/L α-naphthaleneacetic acid (NAA) and the highest number was on 2.0 mg/L BA + 2.0 mg/L NAA. And 1/2 Murashige and Skoog (MS) medium + 0.5 mg/L NAA was the optimal medium for protocorm-like bodies (PLB) turning green. In the subculture of PLB, 1/2 MS supplemented with NAA was more effective, its optimal concentration for growth and multiplication of PLB was 2.0 and 1.0 mg/L, respectively. In adventitious shoots induction, the optimal medium was 1/2 MS + 1.0 mg/L thidiazuron (TDZ) + 0.5 mg/L NAA whose induction rate was up to 56.8%. Additionally, 1/2 MS supplemented with 0.5 mg/L indole-3-butyric acid (IBA) was the best culture medium for rooting. These results may provide available technique for cultivar breeding and large-scale propagation of C. faberi.
Key words: Orchids, Cymbidium faberi Rolfe, propagation, plant growth regulators.