Drenovsky, Rebecca E. , Wygant, Elise M. , Mudery, Stephanie A. , Richards, James .
Potential impacts of soil salinity and salt tolerance on plant nutrient resorption.
Prior to leaf senescence, mobile nutrients are withdrawn from leaves and sent to storage tissues. This process (resorption) is considered one of the most important plant nutrient conservation mechanisms. However, discerning factors constraining potential resorption has remained elusive. We hypothesize that phylogenetic and environmental factors, such as soil salinity, influence plant resorption patterns. We collected senescent leaf tissue from congeners (Artemisia, Atriplex, Chrysothamnus, Sarcobatus, and Tetradymia) found along natural salinity gradients in the Great Basin and Mojave Deserts. Based on preliminary data, we hypothesized that as leaf ion accumulation increased (as measured by leaf ash concentration), N resorption would be less complete due to accumulation of N containing compatible solutes. Contrary to our hypothesis, when analyzing all species or only chenopods (which varied widely in their salt tolerance), there was no relationship between leaf ash and N resorption (R2=0.02 and R2=0.0006, respectively). Surprisingly, when considering the asters, which includes salt sensitive to moderately salt tolerant species, there was a weak, but positive relationship between leaf ash accumulation and N resorption (R2=0.3). Inspecting the observed resorption patterns suggest other factors may drive potential resorption, including but not limited to: 1) the type of compatible solute accumulated; 2) the amount of non-structural N that can be recycled in low nutrient adapted species; and 3) the sex of the plant. Although the number of families selected was low, differing N resorption patterns potentially suggest phylogenetic constraints on resorption. Alternatively, the magnitude of variation in soil salinity among congeners may have been insufficient to detect relationships between leaf ion accumulation and resorption. Greenhouse experiments which independently manipulate soil moisture and salinity are needed to determine the relative influence of these variables on resorption. Understanding potential relationships between soil salinity and resorption may help us better predict how species may respond to anthropogenic soil salinization.
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1 - John Carroll University, Biology Department, 20700 North Park Blvd, University Heights, Ohio, 44118, USA
2 - John Carroll University, Biology Department, 20700 North Park Blvd., University Heights, OH, 44118, USA
3 - University of California Davis, Lawr, One Shields Avenue, Davis, California, 95616-8627, USA
plant nutrient resorption
Great Basin Desert
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM