Figure 2: Lignin staining and autofluorescence of Gossypium hirsutum stems and petioles. Stem cross sections were examined (A) after Mäules reaction, and (B) with autofluorescence. Various tissue regions are visible in the stems such as cortex (co), cambium (c), vasculature (v), pith (p) and collenchyma (cl). Petiole cross sections were examined (C) after Mäules reaction, and (D) with autofluorescence. Inserts indicate higher magnification of specific cell types: phloem fibres (pf), xylem fibres (xf), xylem vessels (xv), pith (p), and collenchyma (cl). Bars = 50 μM.