INTERACTION OF SEED-COAT MICROFLORA AND SOIL MICROORGANISMS AND ITS EFFECTS ON PRE- AND POST-EMERGENCE OF SOME CONIFER SEEDLINGS

Abstract

Analyses of seed samples of Pinus banksiana Lamb., P. contorta Dougl. var. latifolia Engelm., and Picea glauca (Moench) Voss demonstrated the presence of 12 genera of fungi. Pythium, Phytophthora, and Rhizoctonia were not isolated but typical symptoms of damping-off disease were observed among the seedlings grown in sterilized soil. Surface sterilization of seeds resulted in a significant reduction in emergence of P. banksiana and P. glauca seedlings but not on P. contorta var. latifolia. The cause of this difference is discussed. The post-emergence mortality of P. banksiana seedlings resulting from surface-sterilized seeds grown in sterilized and unsterilized soil was significantly higher than that among the seedlings from untreated seeds. Mortality of P. contorta var. latifolia seedlings was significantly higher among the seedlings from untreated seeds, and that of P. glauca seedlings was higher among the seedlings from untreated seeds and only in unsterilized soil.