Optimal conditions for spore germination and gametophyte and sporophyte production in the autumn fern Dryopteris erythrosora

Abstract

Dryopteris erythrosora (D. C. Eaton) Kuntze is used as an ornamental horticultural crop and landscaping plant, and it is a plant with high development value as an herbal medicine, but there are few studies to proliferate a large amount of plants. This study aimed to determine a suitable method for spore germination, gametophyte proliferation, sporophyte formation, and seedling production in D. erythrosora. Spore germination rate was highest in 1/2 × Murashige and Skoog (MS) medium (92.8%). A suitable medium for prothallus proliferation was selected based on gametophytes produced from germinated spores. A 1 × MS medium was most effective for gametophyte proliferation and active organ formation; moreover, 1 × MS medium containing 1% sucrose without activated charcoal was the most effective growth condition for inducing gametophyte growth and development. The suitable culture soil composition for sporophyte formation was investigated by varying the ratio of horticultural substrate, peat moss, perlite, and decomposed granite. We found that a 2:1 (v:v) mixture of horticultural substrate and perlite accelerated sporophyte formation (155 units). Furthermore, suitable seedlings and transplants for sporophyte seedling growth were determined by varying the ratio of horticultural substrate and decomposed granite, as well as plug tray cell size. For sporophyte seedlings, the greatest growth in root length (92.9 mm) and the most aerial and underground fresh weight (234.1 and 40.3 g, respectively) were observed in a mixture of horticultural substrate and decomposed granite at a 1:2 (v:v) ratio. Our results using tissue culture technology will be provided as a mass production method for substantial industrialization of D. erythrosora plants.