Figure 2.

NO₃ ^– and NH₄ ⁺ net fluxes and expressions of BcAMTs and BcNRTs in B. campestris roots in response to treatments with different N levels. (A) Net NH₄ ⁺ fluxes in different NH₄ ⁺ levels (0.25, and 1 mmol L^–1 NH₄ ⁺). (B) Net NO₃ ^– fluxes in different NO₃ ^– levels (0.25, and 1 mmol L^–1 NO₃ ^–). (C, D) BcAMTs and BcNRTs expression in different N levels, respectively (0.25, and 1 mmol L^–1 NH₄ ⁺/NO₃ ^–). GAPDH was used as internal control. The data represent the mean ± SE (n = 6 in A–B, n = 3 in C–D). Significant differences (P < 0.05) between treatments are indicated by different letters.