Extraction and estimation of the quantity of calcium oxalate crystals in the foliage of conifer and hardwood trees.
The main goal of this study was to develop a method for the extraction and indirect estimation of the quantity of calcium oxalate (CaOx) in the foliage of trees. Foliar tissue was collected from a single tree of each species (five conifers and five hardwoods) for comparison of extractions in different solvents using 10 replicates per species from the same pool of tissue. For each species, calcium (Ca) and oxalate were extracted sequentially in double deionized water and 2N acetic acid, and finally, five replicate samples were extracted in 5% (0.83N) perchloric acid (PCA) and the other five in 2N hydrochloric acid (HCl); three cycles of freezing and thawing were used for each solvent. Total ions were extracted by microwave digestion. Calcium was quantified with an inductively coupled plasma emission spectrophotometer method and oxalate was eluted and quantified using a high performance liquid chromatography method. This experiment was repeated again with two conifer and two hardwood species using four trees per species, and two analytical replicates for each tree. We report here that, regardless of age of individual trees within a species, time of collection or species type, the third extraction in PCA or HCl resulted in near equimolar quantities of Ca and oxalate (r(2) ≥ 0.99). This method provides an easy estimate of the quantity of CaOx crystals using a small sample of foliar tissue. An additional benefit of PCA is that it precipitates the nucleic acids and proteins, allowing the quantification of several free/soluble metabolites such as amino acids, polyamines, organic acids and inorganic elements all from a single sample extract.
USDA Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA rminocha@fs.fed.us.
Rakesh
R
Minocha
USDA Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA.
Bradley
B
Chamberlain
USDA Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA.
Stephanie
S
Long
USDA Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
Swathi A
SA
Turlapati
USDA Forest Service, Northern Research Station, 271 Mast Road, Durham, NH 03824, USA Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
Gloria
G
Quigley
D001901:Botany / Q000379:methods*; D002129:Calcium Oxalate / Q000032:analysis* / Q000302:isolation & purification / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000378:metabolism; D014197:Trees / Q000737:chemistry* / Q000378:metabolism
D002129:Calcium Oxalate
HPLC; aspen; beech; birch; conifers; fir; hardwoods; hemlock; maple; oak; organic acids; pine; spruce