Growth of Polyporus glomeratus, Poria obliqua, Fomes igniarius, and Pholiota squarrosa-adiposa in Media Amended with Manganese, Calcium, Zinc, and Iron

Abstract

Polyporus glomeratus Peck, Poria obliqua (Pers.) Bres., Fomes igniarius (L. ex Fries) Kickx., and Pholiota squarrosa-adiposa Lang are some of the principal Hymenomycetes that incite decay in the most valuable hardwood trees in the northeastern United States: sugar maple, Acer saccharum Marsh.; red maple, A. rubrum L.; yellow birch, Betula alleghaniensis Britton; paper birch, B. papyrifera Marsh.; American beech, Fagus grandifolia Ehrh.; and white ash, Fraxinus americana L. These fungi invade and decay wood that is altered first by host response to injury and then by infection with bacteria and nonhymenomycetous fungi (2) (FIG. 1). This altered wood differs in many ways from clear living wood (3). Two important differences of the dead and discolored wood are its high mineral content and high pH (1, 3). Because Hymenomycetes are in contact with such altered tissues, laboratory studies were conducted to gain some insight into the effect of manganese, calcium, zinc, and iron on the growth of these fungi. Isolates of the fungi were taken from decayed tissues in living trees cut on the White Mountain National Forest in New Hampshire. Inocula were prepared by growing the fungi in 25 ml of a liquid medium, 5 g glucose and 1 g yeast extract per liter of distilled water (5-1GY), in 250-ml Erlenmeyer flasks. The mycelium was washed thoroughly in distilled and deionized water and chopped in a blender. A drop of chopped mycelium was used as inoculum in each flask. The medium used in all experiments was 5-1GY. Amendments to this medium per liter were 0.1, 0.3, and 1.0 mg manganese as MnSO4'H2O; 10, 30 and 100 mg calcium as CaCl122HO2; 0.2, 0.6, and 2.0 mg zinc as ZnSO47H2O; and 0.2, 0.6, and 2.0 mg iron as FeNH4(SO4)2 12H20. The pH was adjusted to 6 in all media before autoclaving. The cultures were incubated at 25 C. Dry weight of mycelium, pH, and color of filtrate were recorded after 23 and 24 days. The experiments were repeated several times, and only slight variations occurred. A summary of the results is given in TABLE I. 604