Immunofluorescence of TLPs in cross-sections of phloem of diverse poplar tissues. Panels A and B, young petiole sections (LPI 3); panels C and D, older petioles (LPI 11); panels E and F, young midvein (LPI 3); panels G and H, old midvein (LPI 11) panels I and J, stem (LPI 11) cross-sections, respectively, labeled with TLP1 antiserum. Panels A, C, E, G and I show bright field images, and panels B, D, F, H and J show the corresponding immunofluorescent images. PH, phloem; PF, phloem fibres; and XV, xylem vessels. Arrows indicate labeled sieve elements and asterisk indicates position of phloem parenchyma cell. Scale bar = 20 μm.