Cold Tolerance in Olive Leaves of Three Cultivars Related to Some Physiological Parameters during Cold Acclimation and De-Acclimation Stages

This research studied changes in antioxidant enzymes activity, Total Soluble Proteins (TSPs), Malondialdehyde (MDA), and proline content in the leaves of three olive (Olea europaea L.) cultivars (Amphisis, Gorgan, and Manzanilla) at five different dates, and investigated their relationship with cold tolerance. The results revealed that cold-acclimation dramatically increased cold tolerance. Furthermore, antioxidant enzymes activity, MDA, TSP, and proline content increased throughout the acclimation stage, whereas they declined in the de-acclimation stage. The ascorbate peroxidase, catalase, peroxidase, and superoxide dismutase activities in the leaves tissues correlated with the alterations in cold tolerance. Higher TSP, greater antioxidant enzyme activities, and more proline content together with lower MDA content in Amphisis cultivar led to relative improvement in cold tolerance capacity of this cultivar. Our results showed antioxidant enzymes activities, TSP and proline content could be useful indices to screen cold tolerance in olive cultivars.