Fig. 2

The effects of the proteasome inhibition roots treated with DMSO with or without 50 μM MG132 for 4 and 16 h. a Fourty μg of protein were loaded onto an 8 % SDS-PAGE gel, and levels of polyubiquitinated proteins were detected with ubitquitin antiserum. The immunoblot is representative of two other experiments. Membranes were stained with Ponceau Red prior to immunblotting. Immunoblot of Cox2 from the same membrane. b Levels of free amino acids in plants treated with or without MG132 for 0, 4, and 16 h. Lowercase letters represent a significant difference between treatments (p < 0.05, n = 5 replicates). c Cell viability in root tips as determined by fluorescence of fluorescein diacetate, and is representative of 20–30 roots. kDa—kilodalton