Effect of seed provenance and fungal species on bead formation in roots of Piceamariana seedlings

Abstract

The effects of both seed source and fungal species on the formation of beads in roots of Piceamariana (Mill.) B.S.P. were examined. Seed was collected from two sites near Chapleau, Ontario. One provenance was an upland site with sandy soil, the second a lowland site with peaty soil. Seedlings were grown under aseptic conditions in test tubes and inoculated with either Laccariabicolor (Maire), Laccarialaccata (Scop, ex Fr.), Laccariaproximo (Boud.) Pat., or agar plugs. Each constriction or striation on the root was counted as a single bead. These constricted regions were associated with the accumulation of a darkly stained substance and the absence of a Hartig net. Bead formation on first order lateral roots from each treatment was assessed and the data were analyzed for significance with a two-way factorial ANOVA. There was a significant interaction between seed source and fungal species on the numbers of beads formed. Bead formation was significantly more common on the lowland seed source in the L. laccata treatment only. L. laccata inoculation resulted in the greatest number of beads on first order lateral roots followed by control and L. proximo treatments. Colonization of seedlings with L. bicolor resulted in the formation of significantly fewer beads than in the control or any other treatment.