Figure 5.

Changes in apoplastic metabolism of reactive oxygen species and the level of esterification of pectin resulting from RBOHD dysfunction in Arabidopsis grown in nitrate or ammonium as a sole nitrogen source. (a) The level of hydrogen peroxide in extracellular space. (b) The concentration of ascorbate and dehydroascorbate in leaf extracellular washing fluid. (c) Peroxidase activity in cell-wall-associated proteins. The transcript levels of (d) peroxidase 33 and peroxidase 34 and (e) oxidation-related zinc finger 1. (f) The level of unesterified pectin isolated from alcohol insoluble residue. Comparison tests between rbohd and WT plants were performed on the mean experimental conditions for the nitrate (light grey) or ammonium (dark grey) growth regime separately. Statistical differences calculated using one-way analysis of variance (ANOVA) with Tukey’s post hoc test are indicated at p-value ≤ 0.01 ** and p-value ≤ 0.05 *.