Evaluation of some cold-induced responses in bread and durum wheat plants

In this study, the induced responses of acclimated and non-acclimated genotypes of bread wheat (Triticum aestivum L.) (Norstar) and durum wheat (Triticum turgidum L.) (Gerdish and SRN) to cold stress have been assayed by detecting electrolyte leakage index (ELI), malondialdehyde content (MDA) and the activity of antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase and guiacol peroxidase). Wheat genotypes showed different responses to thermal treatments (23 and -5°C). After exposing plants into cold stress, along with decreasing of damage indices the antioxidative activities increased particularly in acclimated plants so that the maximum and minimum activity of enzymes belonged to Norstar and SRN plants. Acclimated plants showed more readiness in facing up cold stress in Norstar plants compared to durum wheat so that the minimum damage indices and the maximum enzyme activities were observed. The results have shown a potent variety in the level and speed of cell responses in these genotypes. Simultaneous changes of damage indices (ELI and MDA results) and antioxidative activities showed that these enzymes accompanied with other defense mechanisms increased cold tolerance and/ or enhance plant survive in wheat and can cause plant recovery even after sever cold stress. The short-term cold acclimation increased genetic capacity in wheat genotypes so that the degree of tolerance in Norstar was higher than that of durum genotypes. Such defense and damage indices may be used as cold tolerance marker in evaluation of genotypes in a short-term cold stress profitably in a short time and low cost.