Figure 2. Effect of different N sources on the expression of five ANR1-related genes in rice roots.

Rice seedlings were grown in liquid culture for 14 days with 2.88 mM KNO₃ as the sole nitrogen source and then N starved for 3 d. CK, continuous N; −N, starved for 3 d; +KNO₃, resupplied with 2.88 mM nitrate; +NH₄Cl resupplied with 2.88 mM NH₄ ⁺; and +Gln, resupplied with 2.88 mM glutamine; +NH₄NO₃, resupplied with 1.44 mM NH₄NO₃. The value of related genes were normalized to its CK control respectively. The mRNA of OsActin was used as the reference. Error bars represent _{SE. LSD} values were calculated at the probability of either 5% (*, p<0.05) or (**, P<0.01).