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Abstract Detail


Ecophysiology

Scholten, Melissa [1], Zimmerman, Shawna [2], Shaw, Nancy [1], Serpe, Marcelo [2].

Environmental regulation of dormancy loss in Lomatium dissectum seeds.

Lomatium dissectum (fernleaf biscuitroot) is a perennial, herbaceous plant found in semiarid habitats of the Western United States. At the time of dispersal, L. dissectum seeds are dormant and have underdeveloped embryos. To break dormancy and promote embryo growth, we exposed the seeds to dry-after ripening, warm-moist conditions, and cold stratification. Only cold stratification promoted embryo growth. Optimal temperatures for embryo growth were between 4 and 7ºC; embryo growth was negligible at stratification temperatures of 1.5 and 10ºC. During 12 weeks at 4 or 7ºC, the embryos grew from 1 to 7 mm, which is approximately the full length of the seed. Constant exposure to temperatures of 4 and 7ºC also resulted in germination, but to different extents. After 15 weeks of stratification, germination was higher at 4ºC (80%) than at 7ºC (40%). Seeds buried in the field and exposed to natural winter conditions showed similar trends. Under field conditions, seeds experienced about 14 weeks of temperatures between 0 and 10ºC. Within this period, the embryos grew and seed germination reached a maximum of about 50%. No further increase in germination was observed when soil temperatures were above 10ºC. Our study indicates that the release from dormancy in L. dissectum requires long periods of stratification. Furthermore, seeds of this species do not require transfer to warmer temperatures for germination to occur and such transfer may reduce germination. Conditions associated with the release from dormancy in L. dissectum appear to be an adaptation to the climatic regime of the Great Basin to trigger germination in early spring.


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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

Keywords:
seed germination
dormancy.

Presentation Type: Poster:Posters for Topics
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P69010
Abstract ID:1914


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