In vitro seed germination, plantlet growth, tuberization, and syntheticseed production of Serapias vomeracea (Burm.f.) Briq.

Abstract

Orchids are considered recalcitrant plants in in vitro propagation. Due to the lack of appropriate micropropagation techniques for mass production and damage to their ecological distribution posed by local gatherers, these species are threatened with extinction, including Serapias vomeracea (Burm.f.) Briq. In this research, we put forward a complete micropropagation method covering in vitro micropropagation, synthetic seed formation, germination in soil, and acclimatization to ambient conditions. To the best of our knowledge this is the first report of successful synthetic seed formation and germination of S. vomeracea. Initially, seeds were germinated in different culture media and also media supplemented with different concentrations of plant growth regulators. Effects of plant growth regulators on tuber formation, glucomannan contents, and different growth parameters were evaluated throughout the study. The best germination rate (84.03%) was achieved on Orchimax including activated charcoal medium and supplemented with 2.0 mg/L 6-benzyladenine. The longest shoot elongation amongst plantlets was observed on the same medium supplemented with 0.25 mg/L thidiazuron, whereas 2.0 mg/L indole-3-butyric acid favored leaf formation. Higher indole-3-butyric acid concentrations were found to be more effective in the formation and elongation of roots. Orchimax medium supplemented with zeatin (2.0 mg/L) was superior to the others in terms of tuber formation and glucomannan content therein. Adaptation of seedlings to soil conditions and germination abilities of synthetic seeds were also studied and seedlings were successfully acclimatized and adapted to soil conditions.