Effect of Arsenic on Grx15 mutant lines, root and leaf growth, and root respiration. A, Quantification of the primary root length of GrxS15 mutant lines, grown for 9 d on vertical MS agar plates as seen in B. Percentages shown are calculated with the value measured under control conditions set as 100% for the individual line. A two-way ANOVA was performed: n = 27–30 F(6/332) = 44.13, P < 0.0005, see Supplemental Figure S6. B, Root length phenotype of 9 d old GrxS15 mutant seedlings compared to wild type on vertical MS agar plates supplemented with 5 µM arsenite and 200 mm arsenate compared to control plates. Exemplary images are shown. C, Rosette area measurements of GrxS15 mutant lines compared to wild type, measured after 11 d of growth on horizontal agar MS plates. Percentages shown are calculated with the value measured under control conditions set as 100% for the individual line. A two-way ANOVA was performed: n = 17–20, F(6/216) = 9.61, P < 0.0005, see Supplemental Figure S5. D, Oxygen consumption rate (OCR) of root tips of GrxS15 mutant lines compared to wild type when grown for 10 d on MS agar plates supplemented with arsenate and arsenite compared to control plates as in B. Percentages shown are calculated with the value measured under control conditions set as 100% for the individual line. A two-way ANOVA was performed: n = 15-39, F(6/261)=3.19, P = 0.005, see Supplemental Figure S7.