Toolik Lake E. Vaginatum Root Mineral Nutrition [Welker, J. and J. Fahnestock]

Soil cores of 5cm diameter and 20cm depth were taken at approximately 2 week intervals during the 2001 growing season. Three age classes of Eriophorum vaginatum roots (gray (senesced), brown (suberized) and white (active)) were extracted from the cores. Following extraction, cores were cut into 5 4cm sections and sorted for roots within 1 week of extraction. Prior to processing, cores were refrigerated at ~5(C. Some root samples were unwashed, then dried at 70(C for 48 hours prior to coupled combustion/reduction and gas chromatography analysis (CHN-1000, LECO Corporation). Additional samples were washed, and some unwashed, then analyzed using the soil-corrected method (Hunt et al., 1999). Unwashed roots were presumed to retain nutrient characteristics of the rhizoplane. Soil-corrected washed and unwashed root analysis was presumed to estimate nutrient concentrations specifically in the roots, provided a check upon the potential error associated with different degrees of washing and allow for correction of unwashed combustion/reduction and gas chromatography analyzed roots.