Acknowledgements
The authors are thankful to Bjorn Karlsson from the Biotron Laboratory at the University of Wisconsin for technical service and support in the greenhouse, Jesse Nippert at Kansas State University and Ben Harlow at Washington State University for University for help with elemental analyses, and Jeff Merriam and Jan Hislop at the USDA Northern Research Station for technical support with the inorganic ion analysis. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.