摘要 : Germination tests for seeds of many species require moist prechill at 2-5 deg C to break dormancy. In practice, however, seeds are sometimes prechilled at temperatures as high as 10 deg C. To document the importance of prechill te... 展开 Germination tests for seeds of many species require moist prechill at 2-5 deg C to break dormancy. In practice, however, seeds are sometimes prechilled at temperatures as high as 10 deg C. To document the importance of prechill temperature and duration, seeds of 12 wildflower species native to Utah (Balsamorhiza sagittata, Castilleja applegatei, C. chromosa, C. flava, C. linearifolia, C. rhexifolia, C. scabrida, Cleome serrulata, Pedicularis groenlandica, Penstemon cyananthus, P. eatonii and P. sepalulus) were subjected to a series of laboratory germination treatments with 0, 4, 8, 12 and 16 weeks of prechill at 1, 3, 5, and 7 deg C followed by 4 weeks of incubation at 10/20 deg C. Viability evaluation for each species was estimated using a tetrazolium test. Seeds of all species were dormant without prechill, and very few of the collections showed a significant response to 4-week prechill. Prechill at 7 deg C was largely ineffective and only C. linearifolia and C. serrulata responded to prechillat 5 deg C. Seeds of P. cyananthus and C. flava responded positively to prechill, but 3 deg C resulted in slightly higher germination than did 1 deg C. P. eatonii and P. sepalulus required more than 8 weeks of prechill at 1 or 3 deg C for germination toexceed 35 percent. For seeds of B. sagittata, C. scabrida and C. chromosa, germination response increased with increasing prechill duration up to 16 weeks. Finally, C. rhexifolia, C. applegatei and P. groenlandica had maximum germination percentages < 40percent, regardless of prechill temperature or duration. Discrepancies between maximum germination percentages and total viability indicate that prechill for periods longer than 16 weeks may be necessary for many seeds to germinate. Because such long periods are impractical for seed testing, tetrazolium staining or germination tests that include the use of dormancy-breaking chemicals should be considered. 收起