Pistachio is sensitive to late-spring frost, and cold injury may occur when temperatures decline rapidly. In this study, selected physiological traits and the expression of specific genes associated with frostbite-induced temperature hypersensitivity, namely CLO, ICE1, and Dehydrin, were evaluated. The results demonstrated that physiological parameters such as proline content, electrical conductivity (EC), and the activity of enzymes associated with cold stress tolerance, including catalase, superoxide dismutase (SOD), and ascorbate peroxidase (APX), increased in reproductive organs (flowers and fruits) under temperature treatments, as expected. The levels of soluble sugars, ion leakage, and proline varied between organs and treatments, with the highest concentrations observed in both flowers and fruits at –2 °C. In contrast, the highest chlorophyll content in flowers was recorded at 2 °C. Enzyme activities (catalase, SOD, and APX) peaked in flowers at 0 °C. Gene expression analysis revealed that the CLO gene showed the highest expression at –2 °C in the flower organ, while the lowest expression level across all 24 experimental groups was recorded for the CLO gene in the fruit organ at 4 °C. In conclusion, the response of pistachio to cold stress varies considerably depending on temperature and organ type. Overall, decreasing temperatures triggered accelerated and enhanced gene expression, whereas higher temperatures were associated with the down-regulation of these cold-responsive genes.
Mohammad, F. , Afshari, H. , Kashefi, B. , Laei, G. and Zarrinpour, V. (2026). Assessment of Chilling Stress Effects on Physiological and Biochemical Attributes and Gene Expression on ‘Abbas Ali’ Pistachio Cultivar. International Journal of Horticultural Science and Technology, 13(3), 507-522. doi: 10.22059/ijhst.2025.389318.1013
MLA
Mohammad, F. , , Afshari, H. , , Kashefi, B. , , Laei, G. , and Zarrinpour, V. . "Assessment of Chilling Stress Effects on Physiological and Biochemical Attributes and Gene Expression on ‘Abbas Ali’ Pistachio Cultivar", International Journal of Horticultural Science and Technology, 13, 3, 2026, 507-522. doi: 10.22059/ijhst.2025.389318.1013
HARVARD
Mohammad, F., Afshari, H., Kashefi, B., Laei, G., Zarrinpour, V. (2026). 'Assessment of Chilling Stress Effects on Physiological and Biochemical Attributes and Gene Expression on ‘Abbas Ali’ Pistachio Cultivar', International Journal of Horticultural Science and Technology, 13(3), pp. 507-522. doi: 10.22059/ijhst.2025.389318.1013
CHICAGO
F. Mohammad , H. Afshari , B. Kashefi , G. Laei and V. Zarrinpour, "Assessment of Chilling Stress Effects on Physiological and Biochemical Attributes and Gene Expression on ‘Abbas Ali’ Pistachio Cultivar," International Journal of Horticultural Science and Technology, 13 3 (2026): 507-522, doi: 10.22059/ijhst.2025.389318.1013
VANCOUVER
Mohammad, F., Afshari, H., Kashefi, B., Laei, G., Zarrinpour, V. Assessment of Chilling Stress Effects on Physiological and Biochemical Attributes and Gene Expression on ‘Abbas Ali’ Pistachio Cultivar. International Journal of Horticultural Science and Technology, 2026; 13(3): 507-522. doi: 10.22059/ijhst.2025.389318.1013
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