Key message

K/Zn application by spraying at bud swell stage and green tip stage improved freezing tolerance of pistachio flowers due to increased antioxidant enzymes, soluble proteins, soluble carbohydrates, total phenolic and proline contents as well as decreased lipid peroxidation and H₂O₂ content in flower.

Abstract

Spring frost injury to blossoms has been a severe problem in pistachio-harvesting lands of Iran. Use of mineral nutrients has been offered as a measure to alleviate or prevent frost harm. The objective of the present study was to investigate the effects of potassium and zinc application on the spring frost damage of pistachio flowers. Treatments included application of three levels of K₂SO₄ (0, 1, and 2%) combined with three levels of ZnSO₄ (0, 0.5, and 1%). The mineral solutions were sprayed on trees two times (bud swell stage and green tip stage) in 2017–2018. Excised 1-year-old twigs were collected during full blooming. The twigs were exposed to three different low-temperature tests (0, − 2, and − 4 °C), and physiological and biochemical changes were evaluated. The most concentrated mineral solutions, especially, 1% K₂SO₄ + 1% ZnSO₄, increased significantly freezing tolerance, the content of soluble proteins, soluble carbohydrates, total phenolic compounds, proline, guaiacol peroxidase, and catalase enzyme activity of flowers. Compared with control, the application of K₂SO₄ in combination with ZnSO₄ decreased hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) concentrations of flowers after freezing tests. The results of the present study could have implications for improving the freezing tolerance of temperate fruit trees cultivated in cold regions by the use of potassium and zinc.

中文翻译：

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开心果花中钾和锌引起的抗冻性与生理和生化变化有关

关键信息

通过增加芽中抗氧化酶，可溶性蛋白，可溶性碳水化合物，总酚和脯氨酸的含量以及降低脂质过氧化和H ₂ O ₂含量，在芽肿期和绿梢期喷施钾/锌提高了开心果的耐冻性。花。

抽象

春季霜冻对开花的伤害一直是伊朗开心果收获地的严重问题。已经提供了使用矿物质营养素作为减轻或预防霜害的措施。本研究的目的是研究钾和锌的施用对开心果春季霜冻损害的影响。处理方法包括施用三种水平的K ₂ SO ₄（0％，1％和2％）以及三种水平的ZnSO ₄（0、0.5和1％）。在2017-2018年期间，将矿物质溶液两次喷洒在树木上（芽肿胀阶段和绿色尖端阶段）。在盛开期间收集了割下的1岁小树枝。将树枝暴露于三种不同的低温测试（0，−2和−4°C），并评估其生理和生化变化。最浓缩的矿物溶液，特别是1％K ₂ SO ₄  + 1％ZnSO ₄，显着提高了花朵的耐冻性，可溶性蛋白质，可溶性碳水化合物，总酚类化合物，脯氨酸，愈创木酚过氧化物酶和过氧化氢酶的活性。与对照相比，K ₂ SO ₄与ZnSO ₄结合使用冷冻测试后，花朵的过氧化氢（H ₂ O ₂）和丙二醛（MDA）浓度降低。本研究的结果可能对提高通过使用钾和锌在寒冷地区种植的温带果树的耐冻性具有影响。