Phenology and wintering capacity of sporophytes and gametophytes of ferns native to northern Japan.

摘要: To investigate life history adaptations to cold climates, the leaf development, sporulation period, growing stage of gametophytes, and frost drought resistance sporophytes gametophytes 67 fern species native Kokkaido were studied. Most ferns common in Hokkaido are summer-green with leaves developing during late May June decaying October. sporulate August early September. Spores dispersed from September germinate before winter begins, forming vegetative prothallia. Gametophytes mature only following summer. Thus as well perennial exposed severe conditions. In order correlate cycles temperate stress, rhizomes, determined. Maximal rhizomes reflects stress conditions their habitats: forest understory damaged at-5°to -17.5°C, epiphytic habitats sustained temperatures -20° to-40°C. The winter-green evergreen resist ranging -25° -40°C. killed by below -5°C. With some exceptions, on floor -40°C much hardier than sporophytes. These results suggest possible restrictive effects climate span period. If is one decisive factors for seasonality expression habitat distribution ferns, sensitive generation must be sporophyte rather gametophyte. gametophyte therefore able colonize which excluded if mechanisms propagation evolved.