UC Davis

Exposure to a chilling temperature of 2.5degreesC for 96 h inhibited the subsequent growth of cucumber seedling radicles at 25degreesC by 92%. Exposing seedling with 5 +/- 1 mm long radicles to acetaldehyde vapour (275 mul l(-1)) or to an aqueous ethanol solution (0.6 M) for 2 h, or to 45degreesC for 10 min before chilling, increased chilling tolerance so that the chilling treatment reduced growth by only 47, 39 or 36%, respectively. All of these effective treatments induced the synthesis of a number of proteins, and suppressed de novo protein synthesis (i.e. the incorporation of [S-35]-methionine) by about 70%. In contrast, treatment for 2 h with an aqueous arsenite solution (100 muM) had no effect on chilling sensitivity or the incorporation of [S-35]-methionine, yet it induced the synthesis of a complement of proteins that were similar to that induced by the effective heat-shock treatment. A unique protein or set of proteins may be responsible for heat-shock-induced chilling tolerance, but none was detected. The ability of various abiotic stresses to suppress protein synthesis may be more important in increasing tolerance to chilling injury than their ability to induce the synthesis of specific proteins.