Results of comparative proteomics analyses of different treatments.

<p>(a) Number of identified proteins showing changes in expression at each treatment time. (b) Venn diagram showing the overlap of up- and down-regulated proteins among 4 d/0 d, 8 d/0 d, and 12 d/0 d. (c) Functional classification of differentially expressed proteins in poplar leaves after Cd treatment. (b) Proteins involved in biotic stress according to MapMan in leaves after 4 d of treatment. Details of the mapped proteins were shown in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0137396#pone.0137396.s005" target="_blank">S2 Table</a>. Positive fold change values (red) indicate up-regulation, whereas negative fold change values (blue) indicate down-regulation. Gray circle mean the protein that is not mapped in the pathway.