FIGURE 1.

Leaf phenotype recorded in Arabidopsis thaliana growing on NH₄⁺ and NO₃^– (control) as the only N source. (A) Leaves were ordered from the oldest to the youngest. (B) Leaf area, and (C) thickness of the leaf lamina of the ninth fully expanded leaf. Mechanical properties of leaves, (D) the tensile strength, and (E) tensile stiffness were measured in fully hydrated fresh leaves and in rehydrated frozen-thawed (1 h at –20°C) tissues.