| MS Description
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Plants may show differences in terms of me … Plants may show differences in terms of metabolite profiles, so-called ‘metabotypes’, even when no visible phenotypic changes can be observed (Hall 2006). To achieve a broad coverage of primary metabolites, GC-TOF/MS-based metabolite profiling was used in this study. As described previously (Kusano et al. 2007), each sample was extracted, derivatized, and analyzed using GC-TOF/MS. Five milligrams fresh weight of plant tissues was used for GC-TOF/MS analysis. The derivatized extracts, equivalent to 55.6 μg fresh weight of plant material, were injected into the GC-TOF/MS instrument. All raw data were pre-processed using a MATLAB script (version 7.0.4, The MathWorks, Natick, MA) implemented by Jonsson et al. (2005, 2006) to perform baseline correction, alignment, and peak deconvolution. Metabolite identifications were performed by comparing their mass spectra and retention time indices to those generated for authentic compounds analyzed on our instrumentation as well as those in the mass spectra and retention index libraries in the Golm Metabolome Database (Kopka et al. 2005; Schauer et al. 2005). To correct the interference, or cross-contribution, between the internal standards and native metabolites because of problems such as insufficient chromatographic resolution, the data were normalized using cross-contribution compensating multiple standard normalization (CCMN) (Redestig et al. 2009). rmalization (CCMN) (Redestig et al. 2009).
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