Figure 7.

Differences of NH₄⁺, NO₃⁻, and NO₂⁻ concentrations of pecan under varying NH₄⁺:NO₃⁻ ratios. Differences of NH₄⁺ concentrations in pecan leaves, stems, and roots under varying NH₄⁺:NO₃⁻ ratios (A). The mean values of NH₄⁺ concentrations in pecan leaves, stems, and roots under varying NH₄⁺:NO₃⁻ ratios (B). Differences of NO₃⁻ concentrations in pecan leaves, stems, and roots under varying NH₄⁺:NO₃⁻ ratios (C). The mean values of NO₃⁻ concentrations in pecan leaves, stems, and roots under varying NH₄⁺:NO₃⁻ ratios (D). Differences of NO₂⁻ concentrations in pecan leaves, stems, and roots under varying NH₄⁺:NO₃⁻ ratios (E). The mean values of NO₂⁻ concentrations in pecan leaves, stems, and roots under varying NH₄⁺:NO₃⁻ ratios (F). Upper capital letters indicate significant differences between organs (p < 0.05), and lowercase letters indicate significant differences between varying NH₄⁺:NO₃⁻ ratios (p < 0.05).