Longitudinal sections of phloem parenchyma cells (PP) and phloem fibres (PF) in mature stem labeled with TLP1 antiserum. Panels A-C show bright field images and panels D-F the corresponding immunofluorescent images. The stem section in panel D was treated without the primary antibody, E was treated with preimmune serum, and F was treated with TLP1 antiserum. Arrows indicate position of labeled phloem parenchyma cells. Scale bar = 20 μm.