Figure 2.

Effect of different nitrogen form (NH₄⁺ or NO₃⁻) on the retention of the P in the cell wall in ‘Nip’ (A) and ‘Kas’ (B) and the pectin content in ‘Nip’ (C) and ‘Kas’ (D). Seedlings were transferred to NH₄⁺ or NO₃⁻ nutrient solution in the presence or absence of P for 1 week. Pectin content is reported by uronic acid content in the cell wall. Data are means ± sd (n = 4). Columns with different letters are significantly different at P < 0.05.