In Vitro Symbiotic Germination Potentials of Some Anacamptis, Dactylorhiza, Orchis and Ophrys Terrestrial Orchid Species

Abstract

Germination and propagation of terrestrial orchids is highly challenging due to their small size seeds and absence of endosperms. Some orchid species are extremely dependent on fungi for germination of their seeds. Although germination occurs symbiotically between the seed and the fungus, it is not coincidental that fungus species are specific to orchid species. Aim of this study is to show the impact of the fungi, isolated from the tubers of ten naturally grown species of orchids, collected from mountainous area of Van province, Turkey, on in vitro symbiotic germination of the seeds. The collected orchids species were Dactylorhiza romana (Seb.) Soo subsp. georgica (Klinge) Soo ex Renz & Taub., Orchis pinetorum Boissier & Kotschy, Orchis spitzelii Saut. ex W.D.J. Koch, Orchis coriophora L., Orchis collina Banks & Solander, Orchis anatolica Boiss., Orchis simia Lamarck, Ophrys straussii H. Fleischmann & Bornmuller, Dactylorhiza umbrosa (Kar. & Kir.) Nevski, Anacamptis pyramidalis (L.) L. C. Rich. In the study from orchid tubers, Rhizoctonia sp., Aspergillus sp., Alternaria sp., Penicillium sp., Trichoderma sp. and Fusarium sp. fungi species are isolated. Firstly, orchid seeds and fungal isolates placed in oat culture medium were transferred to Van Waes & Debergh culture medium in subculture. The highest germination rates obtained in the seeds are 71.19% in Dactylorhiza romana subsp. georgica species with Rhizoctonia sp.; 78.26% in Orchis pinetorum species with Penicillium sp.; 27.77% in Orchis spitzelii species with Fusarium sp.; 83.07% in Orchis coriophora species with Rhizoctonia sp.; 75.00% in Orchis collina species with Fusarium sp.; 38.88% in Orchis anatolica species with Alternaria sp.; 73.91% in Orchis simia species with Fusarium sp.; 91.60% in Ophrys straussii species with Fusarium sp.; 93.75% in Dactylorhiza umbrosa species with Fusarium sp. and 56.00% in Anacamptis pyramidalis species with Rhizoctonia sp. At the end of the study, it was understood that the fungi isolated from their own or other tubers had different effects on the germination of each orchid species.