Extraction and estimation of the quantity of calcium oxalate crystals in the foliage of conifer and hardwood trees

This data publication includes the results of a study to develop a method for the extraction and indirect estimation of the quantity of calcium oxalate (CaOx) in tree foliage. This study included five sites in New Hampshire, four of which were in the Seaboard Lowlands section of the New England Physiographic Province and the fifth in the White Mountain section of the New England Physiographic Province. A large pool of foliar tissue was collected from a single tree of ten different species (five conifer and five hardwoods) in 2010 (Experiment 1). This provided homogeneous samples used to make comparisons of extractions in different solvents. For ten replicates of each species, calcium and oxalate were extracted from foliage in the following sequential steps: 1) double deionized water (DDW), 2) 2N Acetic acid (CH3COOH), and lastly, 3) five of the ten replicates were extracted in 5% (0.83N) Perchloric acid (PCA, HClO4) and the other five in 2N Hydrochloric acid (HCl) by freeze-thawing (3X) in each solvent. Total calcium (Ca), and other elements, were extracted by microwave digestion and quantified with an Inductively Coupled Plasma Optical Emission Spectrophotometer (ICP-OES), oxalate (and other organic acids) using High Performance Liquid Chromatography (HPLC). This experiment was then repeated with two conifer and two hardwood species using four trees per species and two analytical replicates for each tree in June 2014 (Experiment 2).
Method development for the extraction and estimation of calcium oxalate in the foliage of several forest tree species.
For more information about this study and these data, see Minocha et al. (2015).