Fig. 1

Cell wall thickness and lignin content increase in rind tissues of maize internodes with developmental age. a Maize stems at 35, 42, 49, and 63 days after planting add new internodes at their apex and elongate over time. Scale bar, 10 cm. b-g Scanning electron micrographs show cell walls of rind tissue from internodes nearer the apex of the maize stem have thinner cell walls compared to internodes closer to the base. Scale bar, 10 μm. h-m: Phloroglucinol staining intensity increases from faint pink to dark red in stem sections from the apex to base of the maize stem indicating increasing lignin content towards the base. Scale bar, 1 mm