Investigation of some biochemical and physiological changes in leaves of olive (Olea ‎europaea L.) cultivars during cold acclimation and de-acclimation stage ‎

This study was conducted to investigate the changes in the levels of soluble carbohydrate, antioxidant capacity, total phenolic acid and fatty acid composition of olive during cold acclimation and deacclimation related with freezing tolerance (FT). Three olive cultivars, Amphisis, Gorgan and Manzanilla were selected and leaf samples were prepared from field-grown trees from autumn to summer at six times (November, December, December, February, April and July). The FT was measured by exposure to artificial freezing (0ºC to –25ºC). Result showed that there was a significant difference between the olive cultivars in terms of FT at each stage of sampling. The FT of cultivars increased during the cold acclimation stage and declined in deacclimation stage. Soluble carbohydrates, antioxidant capacity, total phenolic content, leaf dry matter, especially from the beginning of cold acclimation until full acclimation, in cold-tolerant –Amphisis– cultivar was more than the Gorgan and Manzanilla cultivars. The highest ratio of unsaturated to saturated fatty acids in both January and July was observed in Amphisis cultivar. Therefore, compounds such as soluble carbohydrates, total phenolic content, and fatty acids can be used as biochemical indicator of FT in screening of olive cultivars.