Germination number of spores and survival rate due to difference in the growth density of prothallus of Dryopteris erythrosora and Cyrtomium falcatum

Abstract

The mainstream breeding technology using ferns is stock-splitting. It is essential to establish a technique that produces sporophytes from spores in order to increase the choice of greening plants and to preserve individuals. The effects of the average weight of the sorus on the survival rate of Dryopteris erythrosora and Cyrtomium falcatum was assessed by evaluating the difference in the spore germination and the prothallus growth density. The average weight of one sorus was calculated from seven individuals for both species. The samples were cultured at 25 ℃ under constant temperature and dark conditions for 16 h (11,000 lux) and 8 h, respectively, for 90 days. The average weight of one sorus was 0.16 mg (0.08－0.26 mg) for D. erythrosora and 0.32 mg (0.19－0.79 mg) for C. falcatum. In both species, a positive correlation was observed between the average weight of one sorus and the germination number of spores. The growth density of the prothallus and the survival rate after 90 days were greater in the individuals with the highest average weight of the sorus in both species. The peak growth density of D. erythrosora and C. falcatum elevated on the 13th and 24th days on average, respectively. For efficient prothallus production, spores were collected from individuals with a heavy sorus and the pots were raised for about 10－30 days after sowing.