The orchids belonging to orchidaceae family are the second largest and most diverse group of plants and are widespread all over the globe, except for in Polar Regions. Phaius tankervillieae, commonly known as Nun's hood Orchid is one of the most widely valued ornamental orchids in the world. Geodorum densiflorum is one of the floriculturally and medicinally important ground orchids. Orchid seeds are small, numerous, and non-endospermic. The germination rate is very slow, and some needs fungal association.
Tissue culture has become the standard method of propagation for the conservation of orchids. In the present experiment, we analyzed the effect of various concentrations of hormones in seed germination and protocorm formation of both species with MS media. The mature capsules of both species were used as an explant for the present study. The seed germination rate of Phaius tankervillieae and Geodorum densiflorum were found to be variable in hormone-free MS medium and MS medium supplemented with various concentrations of hormones.
The quickest germination of Phaius tankervillieae seed was observed on MS basal medium supplemented with 1mg/L kinetin + 1mg/L NAA, which was also found to be the best for the fastest protocorm formation. However, MS medium, when supplemented with 1.5mg/L kinetin + 1mg/L NAA, produced a maximum number of shoots per culture and a maximum number of roots with shoots per culture. The fastest germination of Geodorum densiflorum seeds was observed on MS basal medium supplemented with 2mg/L NAA + 2mg/L BAP and 2.5mg/L BAP+ 0.1% AC which was also found to be the best for quickest protocorm formation.
Kalita, Indrajit & Borah, Anwesha & Barooah, Chandra. (2023). In vitro propagation of threatened terrestrial orchids Phaius tankervillieae (L'Her) blume and Geodorum densiflorum (Lam.) schltr. via seed pod culture. 8. 95-102.