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Abstract Detail


Ecological Section

Donahue, Jacklyn [1], Scholten, Melissa [2], Shaw, Nancy [2], Smith, James F. [1], Serpe, Marcelo [1].

Differences in cold stratification requirements among populations of Lomatium dissectum seeds.

Lomatium dissectum (fernleaf biscuitroot) is a perennial plant found in semiarid habitats of the Western United States. At the time of dispersal, L. dissectum seeds are dormant and have underdeveloped embryos. We investigated the environmental conditions that promote embryo growth and germination. Only cold stratification promoted embryo growth. Optimal temperatures for embryo growth were between 4 and 7ºC; embryo growth was negligible at 10ºC. Constant exposure to 4ºC also resulted in high germination percentages. This was observed for seeds collected at seven sites ranging in elevation from 80 to 1700 m. The four populations collected at elevations between 80 and 180 m had significantly longer mean germination time (14.4 to 16 weeks) than those collected at elevations between 1280 and 1700 m (10.5 to 11 weeks). The longer germination time for seeds collected at low elevation did not appear to result from a negative effect of cold temperatures on germination. Seeds collected at the lowest sites were placed at 4ºC for 12 weeks. Some trays were then kept at this temperature while others were exposed to a daily (12/12 h) temperature regimen of 5/15ºC. The seeds exposed to the alternating temperatures showed lower germination than those maintained at 4ºC. We also investigated the effect of interrupting the stratification period. Following 10 weeks of cold stratification, seeds were dried to 10% water content and kept at room temperature for 8 weeks. Following imbibition, few seeds germinated and only after long periods of cold stratification, the remaining seeds gradually lost their viability. The above results indicate that seeds from the low elevation sites required longer stratification than those from the high elevations. Furthermore, our experiments suggest that seeds that do not complete their stratification requirements during the first year enter secondary dormancy or lose their viability.


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1 - Boise State University, Department of Biological Sciences, 1910 University Drive, Boise, Idaho, 83725-1515
2 - USDA Forest Service, Rocky Mountain Research Station, Boise, Idaho, 83702, USA

Keywords:
seed germination
Lomatium
stratification.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM
Number: PEC020
Abstract ID:403


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