PLS-DA analysis of metabolites. PLS-DA analysis of the complete dataset obtained from the metabolomic analyses using GC-MS of leaves of npq4 (■), wild-type (▲) and oePsbS (●) Arabidopsis plants, grown under (A) controlled conditions and (B) in the field. All metabolite variables were log10-transformed, centred and scaled to unit variance prior to analysis. The PLS-DA score-plot shows the first two components, which were based on the oePsbS and npq4 sample-sets. Predictions were made for the wild-type data using the corresponding PLS-DA model. (A) 2 components: R2X = 0.19; R2Y = 0.89; Q2Y = -0.17. (B) 2 components: R2X = 0.38; R2Y = 0.97; Q2Y = 0.70.