Wednesday, August 29, 2007
Majestic Ballroom (Adams Mark)

Chemometric Study of Ion Changes in Ponderosa Pine Trees Infected with Dwarf Mistletoe

James B. Whitaker, Ben R. Williams, Jay J. Emerick, Arron B. Wolk, and Nathan W. Bower. Colorado College, Colorado Springs, CO

Dwarf mistletoe (Arceuthobium spp.) is a parasitic plant that is widely distributed in coniferous forests of the northern hemisphere. Mistletoe infects and often kills Ponderosa pines (Pinus Ponderosa), a major source of loss to the timber industry. Three dimensional polarization x-ray fluorescence (XRF) was used in conjunction with inductively coupled plasma optical emission spectrometry (ICP-OES) and ion chromatography (IC) in order to characterize the elemental and ion balance interactions of Ponderosa and dwarf mistletoe. A multivariate analysis of the ion balance in host trees at multiple sites found the mistletoe significantly (P < 0.001) disrupts the electrolyte balance used to control stomatal opening, potentially causing additional stress during drought conditions that may ultimately be tied to tree death. Preliminary measurements of abscisic acid levels (P = 0.02) and stable isotope fractionation (P = 0.04) support the ion balance analyses. In contrast to mountain pine beetle (MPB) attack, which is more successful in a chemically diverse host, measurements of the chemical diversity represented by monoterpene profiles indicate that mistletoe infection is not significantly impacted by the degree of chemodiversity in its host.