EFFECTS OF NITROGEN-FERTILIZATION AND PHOTOPERIOD ON BASIDIOME FORMATION OF LACCARIA-BICOLOR ASSOCIATED WITH CONTAINER-GROWN JACK PINE-SEEDLINGS

Container-grown jack pine (Pinus banksiana) seedlings were inoculated with a wild strain of the ectomycorrhizal fungus Laccaria bicolor. See dlings were raised for 24 weeks and were given various nitrogen fertil ization levels as well as long and short day regimes. Basidiomes occur red from week 16 up to the end of the experiment (24 weeks) depending on the culture conditions. Frequency of fruiting reached a maximum wit h the addition of 5-6 mg of nitrogen per seedling. The response of fru iting to nitrogen was enhanced with a short photoperiod. The biomass o f the basidiomes was positively correlated with the biomass of their r espective host plants with proportions ranging from 10 to 35% and with a mean of 20%.