FIGURE 1.

Imaging of PPTCs in Arabidopsis veins using fluorescence staining and scanning electron microscopy. Calcofluor White staining of cleared leaf tissue (A–C) showing presence of PP TCs in a terminating minor vein (arrow in A) and as more continuous linear strands of staining running along major veins (arrows in B). Higher magnification reveals a central band of mottled fluorescence (arrows in C, asterisks mark cell edges) in a PP TC which corresponds to the deposition pattern of reticulate wall ingrowths seen by scanning electron microscopy in these cells (arrows in D). Staining of PP TCs by aniline blue (E, F) shows the same patterns of staining as revealed by Calcofluor White, albeit with superior signal-to-noise properties (see F). Punctate staining indicating the non-continuous development of PP cells into PP TCs along a given length of vein is particularly evident in E. The images in A–D are reproduced from Edwards et al. (2010) and E and F are unpublished data. Staining with aniline blue was performed identically to that of Calcofluor White, except that 0.01 (w/v) aniline blue in 70 mM phosphate buffer, pH 8.5, was used to replace 0.05% (w/v) Calcofluor White. Scale bars: A, B, E = 100 μm; F = 200 μm; C = 5 μm; D = 2 μm.