Chromeleon 7.2 sr4

Amino acid profiles were quantified using a modified version of the procedure described by Fürst, Pollack, Graser, Godel, and Stehle (1990) (link). Leaf material was lyophilized using an Alpha 1-2 LD+ freeze dryer (Christ, Osterode, Germany). About 10 mg plant powder was arly from 0 to 4.4 min to 71.5:28.5, followed by an isocratic step for 0.3 min. From 4.7 to 6.9 min, solvent A reduced further to 43%, followed again by an isocratic step till 9 min. At 9.8 min, the composition reached 0:100 (A:B) and remained for 5.7 min, to wash the column. At 15.7 min, the initial composition of 98:2 (A:B) was used for 4.3 min to re-equilibrate the column for the next run. Amino acids were detected using a Fluorescence detector 3400 RS and UV-Detector 3100 (Thermo Fisher, Dreieich, Germany). Primary amino acids were excited with 337 nm wavelength, whereas the emitted light at 442 nm was measured. Secondary amino acids were excited with 266 nm, and the emitted signals detected at 305 nm. Standards were prepared using the amino acid standard solution from Sigma-Aldrich (AAS18-5ML), stacked with L-Asparagine, L-Glutamine, gamma-Aminobutyrate, beta-Aminobutyrate, L-Tryptophan and Sarcosine (each from Sigma-Aldrich, Hamburg, Germany). Evaluation of the peak areas was done with the software Chromeleon 7.2 SR4 (Thermo Fisher, Dreieich, Germany).