Lethal and Nonlethal Effects of the Organic Horizons of Forested Soils on the Germination of Seeds from Several Associated Conifer species of the Rocky Mountains
Canadian Journal of Forest Research
Describes laboratory tests to determine whether the lethal effect of the O horizon of Picea engelmannii stands on overwintering P. engelmannii seeds (demonstrated in a previous report) also affects seeds of Abies lasiocarpa, Pinus contorta var. latifolia and Pseudotsuga menziesii var. glauca, and whether the O horizons of these associated species have a similar effect. Untreated seeds and seeds treated with a 10% slurry of 50% captan or powdered 75% captan were stratified in Petri dishes in the pure O horizon (unsterilized or autoclaved). In unsterilized P. engelmannii O horizon, the germination of untreated and powder-treated seeds respectively was: P. engelmannii 3.5 and 77.3%; A. lasiocarpa.1.3 and 20.8; P.m. var. glauca 9.5 and 84.8; and P.c. var. latifolia 11.9 and 85.7. O horizons of A. lasiocarpa and P.m. var. glauca were lethal to seeds of the species from which they were derived but only moderately harmful to seeds of other species. The O horizon of P.c. var. latifolia was almost neutral to all seeds. Autoclaving of the O horizons and powder treatment of seeds produced similar results.
Daniel, T. and Schmidt, J. (1972). Lethal and nonlethal effects of the organic horizons of forested soils on the germination of seeds from several associated conifer species of the Rocky Mountains. Can. J. For. Res. 2(3): 179–184.