Responses of Range Grass Seeds to Winter Environments

Abstract

Seeds of annual and perennial grasses were planted in the field in fall, winter, and spring to test the rapidity of their germination at low temperatures. They were brought from the field into the laboratory at frequent intervals and germinated at 10 degrees C. In general, the longer the exposure to field conditions, the more rapid the subsequent germination. After 1 month of exposure to the winter environment, the ranking of species in order of decreasing rapidity of germination (at 10 degrees C) was as follows: cheatgrass (Bromus tectorum), medusahead (Taeniatherum asperum), crested wheatgrass (Agropyron desertorum), Siberian wheatgrass (Agropyron sibiricum), bluebunch wheatgrass (Agropyron spicatum), and smooth brome (Bromus inermis). The order in which seedlings emerged was the same, except that medusahead emerged earlier than cheatgrass. When seedlings are exposed to drought or to competition with other species, rapidity of germination at low temperatures may be important to their survival.