Effects of Temperature on Asymbiotic Seed Germination of Himantoglossum robertianum (Loisel.) P.Delforge

Aim of study: Despite protection by international agreements, millions of orchid tubers are harvested from their natural distribution areas each year. Of these species, Himantoglossum robertianum is locally threatened due to overharvesting and requires precautionary measures to ensure its protection. Reproduction of the species in an asymbiotic environment is imperative for providing ex-situ protection. There are no studies on optimum germination temperature in H. robertianum. This study aimed to germinate H. robertianum seeds in-vitro under asymbiotic conditions.
Area of study: The study was carried out at the Silviculture Laboratories of Bursa Technical University, Faculty of Forestry, Department of Forestry Engineering.
Material and methods: H. robertianum seeds were used in the study. Seeds were germinated in five replications at four different temperatures (10, 15, 20, and 25°C (± 0.5°C). The study was conducted for 275 days under dark conditions with Sıgma-Phytamax P-6668 used as the medium.
Main results: The highest germination was 23.8% at 20°C and germination was not obtained at 10°C. While germination was faster at 25°C in the first 18 weeks, germination accelerated at 20°C after 18 weeks.
Highlights: These results indicate that temperature is an important factor in the germination of H. robertainum seeds.