The rcd1 snc1 mutant accumulates a higher level of H2O2. A, H2O2 is increased in the rcd1 snc1 double mutant at both 22°C and 28°C. Shown are DAB staining of the wild-type Col-0, rcd1, snc1, and rcd1 snc1 grown at two temperatures. B, O2− is decreased in the rcd1 snc1 double mutant at both 22°C and 28°C. Shown is NBT staining of the wild-type Col-0, rcd1, snc1, and rcd1 snc1 grown at two temperatures.