Cold‐acclimation induced changes in freezing tolerance and translatable RNA content in <i>Citrus grandis</i> and <i>Poncirus trifoliata</i>

Abstract

Cold‐acclimation‐induced changes in freezing tolerance and translatable RNA content were compared in seedlings of a relatively cold sensitive citrus species, Citrus grandis L. Osb. cv. Thong Dee (pummelo), and the cold‐hardy citrus relative, Poncirus trifoliata L. Raf. cv. Pomeroy (trifoliate orange). Cold acclimation of pummelo (10 days at 15°C followed by 4 weeks at 10°/5°C, day/night) resulted in a decrease in LT 50 from −6 to −8°C, while in trifoliate orange (acclimated for 7 weeks at 5°C), the LT 50 decreased from −9 to −18°C. Qualitative changes in the in vitro translation profile, revealed by two‐dimensional gel electrophoresis, were observed following cold acclimation in both species. An mRNA for a large polypeptide (ca 160 kDa) was detected following cold acclimation of trifoliate orange. A similar change was not observed in pummelo following cold acclimation.