In vitro direct plant regeneration from somatic embryos developed from the leaf explants of Flickingeria nodosa (Dalz.) Seidenf. through synthetic seed technology

Flickingeria nodosa (Dalz.) Seidenf. is a vulnerable epiphytic orchid bearing short lived flowers. Due to the unavailability of the specific pollinators the fruit setting is difficult. So the alternative method is through regen-eration by using the vegetative propagules. The aim of the present study was to standardize the protocol for direct regeneration of somatic embryos from the leaf explants of Flickingera nodosa and future development of complete plantlets through synthetic seed technology. The young leaves were treated with lower concentra-tion of 0.5 mg/L thidiazuron (TDZ) and inoculated on Knudson C basal medium (KCBM) prepared with diverse concentrations and combinations of auxin and cytokinin to standardize the optimum growth regulator combi-nation. Development of somatic embryos was observed with only adenine sulphate and indole acetic acid (IAA) combination of growth regulator's. The highest number of somatic embryo development was observed in KCBM fortified with 4 mg/L adenine sulphate and 2 mg/L IAA. Triphenyl tetrazolium chloride test confirmed the viability of developed globular and heart shaped somatic embryos through microscopic observation. The developed somatic embryos were encapsulated with sodium alginate (2%) dipped in CaCl2 (100 mM) solution and were incubated for 30 min to make firm, transparent and consistent synthetic seeds. Formed seeds were inoculated on BN3FBM with 2 mg/L adenine sulphate and 1 mg/L IAA for germination. The fully developed plantlets were effectively established with 82% survival frequency after acclimatization and hardening.(c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.