Expression of GFP in hybrid aspen using Agrobacterium -mediated vacuum infiltration. (A-F) Transient expression of GFP in aspen leaves. CaMV35S::EmGFP construct was transformed into hybrid aspen cuttings. Bright field image (A and D), GFP fluorescence (B and E), and GFP fluorescence and chloroplast autofluorescence (C and F) were captured using a fluorescence stereomicroscope. Scale bar = 5 mm (A-C). Areas with a white box in A, B, and C are magnified in D, E, and F, respectively. Scale bar = 1 mm (D-F). (G-O) Transient expression of GFP in various cell types in aspen leaves. GFP signals were observed in epidermal cells (G-I), guard cells (J-L), and mesophyll cells (M-O). GFP fluorescence (G, J, and M) and autofluorescence of chloroplasts (H, K, and N) were captured using a CLSM. GFP signal and autofluorescence of chloroplasts were merged (I, L, and O). Scale bar = 10 μm.