Ecology / Ecologie (CBA/ABC)
Allphin, Loreen , Wyllie-Echeverria, Sandy .
Variation in fruit development among sites, years and life history in eelgrass (Zostera marina).
Seagrasses increase biodiversity and productivity of estuarine and coastal environments and are threatened a variety of natural and human-induced stressors associated with global climate change. While it is clear that water may not be a limiting factor, other abiotic forces such as temperature stress may retard fruit and/or seed development. During the summers of 2005 and 2006, we assessed post-fertilization fruit development in Zostera marina (eelgrass) at a site in the San Juan Archipelago in the northwest corner of Washington State, USA. We computed mean fruit/ovule ratios (including abortion rates at early, mid, and late developmental stages) from randomly sampled mature spathes. Moreover, in 2006, we examined fruit/ovule ratios and embryo abortion rates from mature spathes collected at eight sites throughout the range of Z. marina (eelgrass) within the continental United States (including both west and east coast populations). We found significantly lower seed/ovule ratios in 2006 compared to 2005 at the site in the San Juan Archipelago. Lower fruit/ovule ratios in 2006 were due to extremely high levels of embryonic abortion (> 80%) at the early stage of development. Because abnormally high temperatures (~30 C) were recorded during anthesis at this site in 2006, we suspect the timing of this temperature stress was consistent with peak embryonic susceptibility found in crop species and likely responsible for the higher abortion rate found that year. In addition, we found significant differences in fruit/ovule ratios and variation abortion rates among the eight study sites (including east and west coast populations) surveyed in 2006. We also found significant differences for fruit/ovule ratios associated with life history variation in this taxon. Populations with the perennial habit exhibited significantly lower fruit/ovule ratios and higher abortion rates than populations with the annual habit.
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1 - Brigham Young University, Department of Plant and Animal Sciences, 275 Widtsoe Building, Provo, UT, 84602, USA
2 - University of Washington, Friday Harbor Laboratories, 620 University Road, Friday Harbor, WA, 98250, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 10:45 AM