Rapid Propagation of <i>Rhynchostylis retusa in Vitro</i>

An efficient regeneration system of Rhynchostylis retusa was established to provide technical reference for the application of tissue culture tube seedlings in production. The mixtures of callus and protocorm from aseptic germination were used as explants. The optimal media of each stage was selected for callus proliferation, protocorm occurrence and growth, rejuvenation and rooting via a single, complete combination and orthogonal experiment. The results showed that the optimal medium for callus proliferation, protocorms occurrence and growth was 1/2 Murashige and Skoog (MS) medium adding 50 g·L^?1 banana puree, 0.1 mg·L^?1 α-naphthaleneacetic acid (NAA), 1.5 mg·L^?1 6-benzylaminopurine (6-BA) and 1.0 mg·L^?1 kinetin (KT) with 17.33 proliferation coefficient of callus and 19.63 occurrence coefficient of buds after 90 days. Then the buds occurred from protocorm were cultured on 1/2 MS medium including 100 g·L^?1 banana puree, 1.0 mg·L^?1 NAA, 2.0 mg·L^?1 6-BA and 0.05 mg·L^?1 KT, in which the proliferation coefficient of callus was 10.32 and occurrence coefficient of buds reached 17.87. In the further subculture, the same medium was simultaneously used for callus proliferation, protocorm occurrence and bud growth. The plantlets developed roots in 1/2 MS medium containing 70 mL·L^?1 coconut water and 1.5 mg·L^?1 NAA with 100% rooting rates after 90 days. The survival rate was more than 90% after domestication and transplantation. This regeneration protocol will provide technique foundation for protecting wild resource and developing artificial cultivation.