Scholten, Melissa , Zimmerman, Shawna , Shaw, Nancy , Serpe, Marcelo .
Requirements for embryo growth and dormancy break in Lomatium dissectum seeds.
LOMATIUM dissectum (fernleaf biscuit root) is a perennial, herbaceous plant found in semiarid habitats of the Western United States. This species produces seeds that are initially dormant. We have investigated the anatomical characteristics of the dormant seeds and the effect of various environmental conditions on breaking dormancy. Dormant seeds have underdeveloped embryos that are completely surrounded by the endosperm. In an attempt to promote the growth of the embryo and break dormancy, we exposed the seeds to dry-after ripening, warm-moist conditions, and cold stratification. Warm moist conditions or a combination of dry after-ripening followed by warm-moist conditions did not induce embryo growth. In contrast, cold stratification promoted embryo growth. During 12-weeks of cold stratification the embryo grew from 1 to 7 mm, which is approximately the full size of the embryo. Most of the embryo growth occurred during the first 6 weeks of stratification. Cold stratification also promoted germination. However, after 12 weeks of cold stratification the percent germination was only 20 %. Seeds buried in the field and exposed to natural winter conditions showed similar trends. The embryos grew when soil temperatures ranged between 0 and 10C. Winter temperatures also triggered germination; after 15 weeks in the field germination was about 40%. The presence of underdeveloped embryos in the dormant seeds and the requirement for cold stratification indicate that L. dissectum seeds have morphophysiological dormancy. Furthermore, the release from dormancy appears to require long periods of cold stratification; a characteristic that may lead to the formation of a persistent seed bank.
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1 - USDA Forest Service, Rocky Mountain Research Station, Boise, Idaho, 83702, USA
2 - Boise State University, Department of Biology, 1910 University Drive, Boise, Idaho, 83725-1515, USA
Presentation Type: Poster:Posters for Sections
Location: Auditorium/Bell Memorial Union
Date: Tuesday, August 1st, 2006
Time: 12:30 PM