Isolation and identification of mycorrhization helper bacteria in Norway spruce, Picea abies (L.) Karst.

We have isolated bacteria from bulk soil, the mycorrhizosphere and the hyph osphere of Norway spruce (Picea abies (L.) Karst) seedlings in mycorrhizal association with the fungus Amphinema byssoides (Pers.) J. Erikss. Out of 1 57 bacterial strains, ten (6.4 %) were fluorescent pseudomonads and 12 (7.6 %) were from the genus Bacillus. The selected strain P. fluorescens 53a, t ested for its effect on growth and mycorrhization of Norway spruce seedling s, grown in vitro in the presence of the ectomycorrhizal fungus Paxillus in volutus (Batsch. ex Fr.) Fr., showed a positive effect on growth (fresh and dry weight after one and two months of growth) and mycorrhization (number of mycorrhizal seedlings after three months) and a negative effect on the t otal root length, root surface area and total root volume after 3 months.