1998 Volume 85 Pages 267-278
This is a study of the factors that affect discharge and germination of lichen ascospores. Spore discharges from apothecia of many lichens were shown to be influenced by discharge period, collecting seasons, storage temperatures and storage periods. Tested species had more or less an endogenous rhythm of sporulation fundamentally in the dark without alternation of light and dark. Winter and spring were found to be good seasons for spore discharge of the temperate lichens studied. Even after storage for 1 year at -25℃, many lichens retained the capacity for discharging spores. The spore germination was influenced by medium composition, initial medium pH and culture temperature. Most spores of the species tested germinated on plain agar medium at pH 6 at 15℃. Spores of Letharia species could not be germinated on agar-medium, but did on Gerlite-medium; this is the first case of agar acting as germinative inhibitor(s) of lichen spores. Natural extract medium prevented spore germination of a few species. Spores of some Peltigera spp. germinated on media supplemented resins which can absorb phenolics, therefore, it would appear that spores of these species had self-inhibitor(s).
