Abstract Detail


Santiago-Rosario, Luis [1], Harms, Kyle [2].

Contrasts among cationic phytochemical landscapes in the southern United States.

Understanding the phytochemical landscapes of essential and nonessential chemical elements in plants provides an opportunity to better link biogeochemical cycles to trophic-level interactions. We investigated the formation and regulation of the cationic phytochemical landscape of four key elements for biota: calcium, magnesium, potassium, and sodium. We collected aboveground tissues of plants in Atriplex, Helianthus, and Opuntia, and adjacent soils, across 51, 131, and 83 sites, respectively, across the southern United States. Using multivariate approaches, we modeled the influence of bioclimatic and soil variables on plant cationic composition. Additionally, we determined the homeostasis coefficient for each cation and genus combination and assessed spatial autocorrelation of cations using a Mantel tests approach. Sodium variability was considerably greater than that for calcium, magnesium, or potassium. Calcium, magnesium, and potassium revealed and shared strong homeostatic patterns, in striking contrast to non-homeostatic sodium. Climatic and soil variables explained a large proportion of plants’ sodium composition, but not for calcium, magnesium, and potassium. There was a strong spatial autocorrelation for plant sodium concentrations but not for calcium, magnesium, and potassium across a heterogeneous landscape. Essential elements such as calcium, magnesium, and potassium appeared to be tightly homeostatically regulated across the plant taxa and field conditions we sampled, contrasting sharply with sodium, a nonessential element for most plants. In addition, we provide field evidence for the No-Escape-from-Sodium hypothesis, indicating that plant sodium concentrations tend to increase as substrate sodium levels increase. The pattern found in field conditions suggests a profound influence of sodium as a potential driver of general eco-evolutionary dynamics and substantial influence on trophic-level interactions at local and regional scales.

1 - Louisiana State Univeristy, 103 Life Sciences Building, Louisiana State University, Baton Rouge, LA, 70803, United States
2 - Louisiana State University, 103 Life Sciences Building, Louisiana State University, Baton Rouge, LA, 70803, United States

multivariate analysis
spatial autocorrelation.

Presentation Type: Oral Paper
Number: EPH3001
Abstract ID:322
Candidate for Awards:Phytochemical Best Oral Presentation Award

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