Leaf toughness in maize and teosinte increases in a leaf-specific manner during early ontogeny.

<p>Leaf toughness was measured in old (blue) and young (red) leaves of two teosinte accessions (T62 and T77), a Tuxpeño landrace variety from two collection sites (Talpitita and El Cuyotomate) and two maize hybrid lines (Pactol and Delprim) at three early vegetative growth stages (L2, L4 and L6). Leaf toughness is expressed as the force needed for penetration of the leaf blade and given in Newton (N) (mean ± SE; N = 3–5). Statistically significant effects of plant growth stage or leaf identity on leaf toughness are denoted by asterisks (*<i>P</i> < 0.05; **<i>P</i> < 0.01; ***<i>P</i> < 0.001, ns: not significant; two-way ANOVA without growth stage L2).