This study was undertaken to compare freezing tolerance of 10 commercial Iranian pistachio cultivars in January and March, and to study the relationship between freezing tolerance and changes in the concentration of soluble carbohydrates, total soluble proteins, proline, phenolic compounds, malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and water content of buds in both sampling stages. After subject to six different freeze-temperature tests (−9, −13, −17, −21, −25, and − 29 °C), bud LT₅₀ values were evaluated using the measurement of electrolyte leakage and bud browning. In January, ‘Chrokeh,’ ‘Shahpasand’, and ‘Rezaee’ showed the highest freezing tolerance, whereas ‘Kaleh Ghouchi’ was the least hardy cultivar. Freezing tolerance of all cultivars lessened slightly in March. In this period, ‘Sefid Pesteh,’ ‘Shahpasand,’ ‘Abbas Ali,’ ‘Kaleh Ghouchi,’ and ‘Fandoghi’ showed the least freezing tolerance, while ‘Rezaee,’ ‘Momtaz,’ and ‘Chrokeh’ were the highest hardy cultivars. There were significant differences in all the characteristics mentioned above among pistachio cultivars in both sampling dates. Negative correlations were observed between LT₅₀ values with proline, phenolic compounds, soluble carbohydrates, and total soluble proteins. Also, there was a positive correlation between LT₅₀ values with the concentration of MDA and H₂O₂ on both dates and with bud water content in March. These results indicated osmoregulants are valuable indices to screen freezing tolerance in pistachio cultivars.

这项研究的目的是比较1月和3月伊朗10个商业开心果品种的耐冻性，并研究耐冻性与可溶性碳水化合物，总可溶性蛋白，脯氨酸，酚类化合物，丙二醛（MDA）浓度变化之间的关系，过氧化氢（H ₂ O ₂）和两个采样阶段的芽含水量。经过六次不同的冷冻温度测试（−9，−13，−17，−21，−25和− 29°C）之后，芽LT ₅₀使用电解质泄漏和芽褐变的测量值来评估该值。一月份，“ Chrokeh”，“ Shahpasand”和“ Rezaee”表现出最高的耐寒性，而“ Kaleh Ghouchi”则是最不耐寒的品种。3月份所有品种的耐冻性略有下降。在此期间，“ Sefid Pesteh”，“ Shahpasand”，“ Abbas Ali”，“ Kaleh Ghouchi”和“ Fandoghi”显示出最低的耐寒性，而“ Rezaee”，“ Momtaz”和“ Chrokeh”则是最高的耐寒性品种。在两个采样日期中，开心果品种的上述所有特征均存在显着差异。LT ₅₀值与脯氨酸，酚类化合物，可溶性碳水化合物和总可溶性蛋白质之间观察到负相关。而且，LT之间存在正相关两个日期的MDA和H ₂ O ₂浓度以及三月的芽含水量均为₅₀。这些结果表明，渗透压剂是筛选开心果品种耐冻性的有价值指标。