Figure 2

Representative micrographs of cotton fibre during development, using polarizing (POL) and differential interference contrast (DIC) optics to reveal the onset of wall thickening near 20 days post anthesis in G. hirsutum : (A) domesticated TM-1; (B) wild var. yucatanense. (A, B) The main micrographs are POL images, showing white birefringence of cellulose against a black background, whereas the insets are DIC images revealing the angle of microfibrils in the winding layer (grey striations, with the angle emphasized by the white line). The magnification bar in the lower left corner of (B) applies to the whole figure and it represents 100 μm for the main POL images and 20 μm for the DIC images in the insets.