The phytochemical landscape of microelements, especially sodium, has been understudied across large heterogenous soilscapes. Sodium represents a vital microelement in the development of animals but differs in its importance in plants providing a suitable system to study micronutrient stoichiometric mismatch across terrestrial environments. A handful of studies have shown that sodium phytochemistry is highly variable across continental ranges but mainly relate elemental concentrations to coastal proximity disregarding direct soil geochemistry. What remains unknown is the sodium phytochemical landscape across a natural heterogeneous soilscape, which is the focus of the current study. We collected 102 populations of sunflowers (Helianthus) and adjacent soil samples across natural and roadside areas from Mississippi to California during summer 2018. Analysis of sodium concentrations of soil and plant samples were conducted using inductively coupled plasma with atomic emission spectroscopy (ICP-AES). Sodium concentrations values were correlated using a general linear model in R.
Results/Conclusions
Results showed that there is a weak relationship between sodium soil concentration and plant sodium content (F1,100=6.89, R2=0.064, p=0.01). However, plants displayed a high variation in sodium plant content across the phytochemical landscape that ranged from 2.92-18,251.94 ppm (mean=703.27, SD=2,487.05). These results suggest that even though sodium soil concentrations are weakly correlated to plant sodium content, plants still display high variation in sodium content which, in turn, could have significant effects on the stoichiometric mismatch between plants and herbivores. Sodium stoichiometric mismatch could potentially have significant effects on herbivore phenotypic development and fitness across a varied phytochemical landscape. Our findings represent one of the first studies aimed to understand the phytochemical landscape of micronutrients across a heterogeneous landscape and its link trophic level interactions.