PROTEIN-SYNTHESIS INHIBITORS BLOCK HIGH-TEMPERATURE ACCLIMATION IN BELL PEPPER LEAVES

Pepper (Capsicum annuum L. 'Early Calwonder') leaf disks were vacuum-i nfiltrated in distilled water (control), anisomycin, aurintricarboxyli c acid, cycloheximide, ethionine, norvanine, or puromycin to determine whether protein synthesis inhibitors blocked high-temperature acclima tion. After infiltration, one-half of the leaf disks were placed in an incubator at 24C as a control, and the other half were kept in a wate r bath at 38C for 2 h to induce acclimation. Test tubes containing the disks then were placed in a water bath at 50.5C for 0, 1, 5, 10, 15, 25, 35, or 50 minutes. Thermotolerance was evaluated using electrolyte leakage. High-temperature acclimation was blocked in all six protein synthesis-inhibitor treatments. Only control disks infiltrated with di stilled water acclimated. It seems that protein synthesis is required for high-temperature acclimation in bell pepper leaves.