Drenovsky, Rebecca , Thornhill, Megan , Khasanova, Albina , Futrell, Caryn , Grewell, Brenda .
Soil salinity does not impede nitrogen resorption in Spartina densiflora.
For many salt marsh species, there is a strong link between nitrogen (N) nutrition and salinity tolerance. High N requirements have been linked to accumulation of N-containing compatible solutes, which help maintain a favorable water potential gradient under salinity stress. Despite the important role N plays in salinity tolerance, little work has explored how salinity stress may influence N resorption, a mechanism which enables plants to recycle N prior to leaf senescence. We hypothesized that the need for compatible solute accumulation under high salinity would impede N resorption in senescing leaves. We collected Spartina densiflora individuals from four populations along the California coast and raised them in the greenhouse under three salinity levels(2 mM, 650 mM, 1500 mM), which approximated freshwater, brackish water and seawater concentrations. Leaf ash (a proxy for total leaf ionic concentration) significantly increased with salinity(P<0.0001). Contrary to our hypothesis, senesced leaf N (a measure of resorption) did not vary among salinity treatments (P>0.05), and there was not a significant correlation between leaf ash and senesced leaf N (P>0.05). Despite plants being grown at high N supply, mean senesced leaf N was at or near complete resorption levels, indicating that S. densiflora is proficient at N resorption. These data suggest that tight internal N recycling has been selected for in this species, which may relate to its salt tolerant physiology.
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1 - John Carroll University, Biology Department, 20700 North Park Blvd, University Heights, OH, 44118, USA
2 - United States Department of Agriculture-Agricultural Research Service, Exotic and Invasive Weeds Unit, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
3 - USDA-ARS Exotic and Invasive Weeds Unit, Department of Plant Sciences, University of California, Davis, One Shields Avenue, Davis, CA, 95616, USA
Presentation Type: Poster:Posters for Sections
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:45 PM