Figure 5.

Effect of the external pH on the transcript accumulation of NRT1.1, NIA1, NIA2, and NiR in roots of WT (Col) and G′4-3 plants. Plants were grown hydroponically on standard nutrient solution containing 1 mm NH₄NO₃ as nitrogen source for 7 weeks and transferred for 1 week to solutions buffered with 4.4 mm MES (pH 6 or pH 5 with Tris). Total RNAs were analyzed by northern blot.