Abstract
Most temperate plants can increase their freezing tolerance during cold acclimation. To increase freezing tolerance, plants need not only low temperature but also light in general. However, it is not well known what colors of the light and photoreceptors involve in regulation of cold acclimation. Here we showed that wild type Arabidopsis thaliana plants cold-acclimated under blue light gained a greater freezing tolerance than those cold-acclimated under red light. In addition, when cold-acclimated under blue light, blue light receptor (cryptochrome) knock-out mutants (cry1cry2) exhibited lower freezing tolerance than wild type. However, there were no significant differences of total sugar contents in wild type that were cold-acclimated under red or blue light conditions. These data collectively suggested that blue light received through cryptochormes during cold acclimation is more efficient in increasing freezing tolerance than red right but the difference is not likely due to the extent of sugar accumulation.
