Figure 8.

¹⁵N concentration and ¹⁵N distribution ratio in WT and transgenic lines. WT and transgenic seedlings were grown in 1 mM NH₄ ⁺ for 3 weeks and nitrogen starved for 1 week. ¹⁵N concentration in the roots and shoots of the WT and transgenic lines under the nutrient solution containing (A) 0.2 mM ¹⁵NO₃ ^– or (B) 1.25 mM ¹⁵NH₄ ¹⁵NO₃ for 12 h. The shoot-to-root ratio of the total ¹⁵N content at (C) 0.2 mM NH₄ ⁺ or (D) 1.25 mM ¹⁵NH₄ ¹⁵NO₃. DW, dry weight. Error bars: SE (n = 4). The different letters indicate a significant difference between the transgenic line and the WT (P < 0.05, one-way ANOVA).