Optima8300 dv icp oes spectrometer

Formaldehyde (36%) was purchased
from VWR; phosphorous acid (99%) and hexylamine (98%) from Fluka Chemical
Co.; 2-ethylhexylamine (98%), La(NO₃)₃·6H₂O, and propylamine hydrochloride from Sigma-Aldrich; ethylamine
hydrochloride (98%), butylamine (99%), and Y(NO₃)₃·6H₂O (99.8%) from Merck; and Lu(NO₃)₃·H₂O from abcr and amylamine (98%) from TCI
chemicals. All of the chemicals were reagent grade and used without
further purification. NMR measurements and titrations were performed
on a Bruker Avance III 300 MHz-spectrometer, and NMR data was processed
with Bruker TopSpin 4.0.8. IR spectra were measured by Bruker Alpha
FT-IR. Elemental analyses were done by an Elementar Vario EL III-analysator.
Lanthanoid concentrations were determined by a Perkin Elmer Optima
8300 DV ICP-OES- spectrometer.

Concentration of P in the plants from the mini-rhizotrons was measured after drying at 60 °C for six days and weighing. Due to very little biomass in some treatments, roots and shoots of each plant were burned together in a muffle furnace at 550 °C for 4 h. Digestion was carried out in 25% HCl according to Page et al. [54 ]. Element concentrations were measured using an Optima 8300 DV ICP-OES spectrometer (Perkin Elmer, Waltham, MA, USA). The P concentration was estimated as mg P per g plant dry matter.