Unsupervised spatial segmentation of eight independent MALDI MSI analyses covering the first days of barley germination using WHIDE.

<p>A: Image scans with outlines of labeled seed compartments. B: Cluster analysis of all mass spectra of the whole grain areas. C: Cluster analysis of all mass spectra of the embryo areas as annotated in A. D: Cluster analysis of all mass spectra of the endosperm as annotated in A. E: Effect of the cluster granularity (7, 21, 56 clusters) on mapping results, exemplarily shown for four days germinated barley (G4d) from analysis B. The visualized cluster, granularity was set to 7 in A, B, and C to assign clear cluster profiles (right panels). 93 <i>m/z</i> values were selected for spatial segmentation in all analyses. Their contribution to the distinct clusters is indicated by the bar size in the right panels; for <i>m/z</i> identification see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150208#pone.0150208.t001" target="_blank">Table 1</a>. For an interactive exploration of the results in WHIDE see <a href="https://ani.cebitec.uni-bielefeld.de/barleymsi" target="_blank">https://ani.cebitec.uni-bielefeld.de/barleymsi</a>.