Ex Vitro Seedling Development from In Vitro Rhizome-Like Bodies in Eulophia promensis Lindl.: A New Technique for Orchid Propagation

This communication describes in vitro seed germination, embryo differentiation, and ex vitro seedling production from in vitro rhizome-like bodies of a terrestrial orchid, Eulophia promensis Lindl. Effects of two nutrient media, namely, Murashige and Skoog (MS) and Phytotechnology Orchid Seed Sowing medium (P723) supplemented with 6-benzylaminopurine (BAP; 0.5–1.0 mgL−1) and/or α-naphthalene acetic acid (NAA; 0.5–1.0 mgL−1) and activated charcoal (2.0 gL−1), were studied on seed germination and subsequent development of embryos. Maximum seed germination (100%) was recorded in P723 medium fortified with 1.0 mgL−1 BAP + 2.0 gL−1 activated charcoal. The different developmental stages of protocorm morphogenesis were traced out. In subsequent subcultures, the protocorms proliferated profusely and developed rhizome-like bodies (RLBs) with numerous hair-like structures. These RLBs were transferred to pots containing potting mixture composed of humus + coir dust + saw dust (1 : 1 : 1) where ∼80% of RLBs survived and produced 1–3 seedlings per RLB. This is the first time report for in vitro germination of seeds and ex vitro seedling production from in vitro raised RLBs in Eulophia promensis. This is a time saving and cost effective protocol that could be extended to other economically important, rare, and endangered orchids for propagation and conservation.