Gremer, Jennifer R. .
Resource storage and prolonged dormancy: Is it better to stay belowground?
Prolonged dormancy is a life history stage where adult plants fail to re-sprout for one or more growing seasons. Demographic studies on the potential fitness consequences of this intriguing strategy have yielded contradictory results. Because plants must use stored resources to initiate seasonal growth as well as to survive dormant episodes, internal resource dynamics have often been invoked to interpret results from demographic studies. However, no study has directly compared stored resource dynamics in dormant and emergent plants. I investigated seasonal changes in stored resource pools in emergent and dormant plants of Astragalus scaphoides, a native perennial wildflower with large underground storage organs. I addressed two questions: a) are plants that enter into prolonged dormancy resource depleted relative to emergent plants? and b) does prolonged dormancy deplete stored resources? I harvested plants and compared stored available carbon, nitrogen, and phosphorus between dormant, vegetative, and reproductive plants. Plants entering dormancy were not resource depleted relative to emergent plants. Surprisingly, and contrary to my prediction, dormant plants actually concentrated resources during the growing season. My data suggest that prolonged dormancy may be a beneficial strategy, allowing plants to avoid the risks of emerging above ground without incurring a resource cost.
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1 - University of Montana, Division of Biological Sciences, 32 Campus Drive, Mail Stop 4824, Missoula, MT, 59812, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Tuesday, July 29th, 2008
Time: 2:15 PM