Environmental conditions of the field where P. deltoides trees were located and quantitative distribution and functional classification of apoplast proteome. (A) Average monthly high and low temperatures, precipitation, and day-length from 2003 to 2007. Orange-color shows the sampling time of tissues for apoplast proteome, whereas the shaded background indicates the sampling of leaf tissues for transcript analysis using microarrays. Developmental stages of leaves and shoots are shown on the right during sampling. Bar = 2 mm (September-March) and = 1 cm (April-August). (B) High/low temperatures and precipitation during sampling for apoplast proteome analysis (April-July, 2007). Arrows indicate flooding times. The red bar shows normal Melampsora infestation. (C-E) Quantitative distribution of leaf and stem apoplast proteins. 84 proteins (38+46) were detected with 2-D PAGE, whereas 106 proteins (60+46) were detected with 2-D LC. Both 2-D PAGE and 2-D LC detected 46 proteins. (F) Quantitative distribution of leaf, stem, and root apoplast proteins. 2-D PAGE-based poplar root apoplast proteome was from Dafoe and Constabel . Functional classification of leaf (G) and stem (H) apoplast proteins.