Pistachio (Pistacia vera L.) is an economically important nut crop that is prone to drought stress since it is mainly produced in arid and semi-arid regions. Considering the possible impact of salicylic acid (SA) on drought tolerance of pistachio, several physiological and biochemical responses of pistachio seedlings to foliar application of SA under progressive drought treatment were investigated. Application of SA increased the content of pigments, chlorophyll, and carotenoids, and improved the accumulation of osmolytes such as proline and total soluble carbohydrates leading to preserve photosynthetic apparatus and relative water content. Moreover, SA application reduced the drought-induced levels of H₂O₂ and lipid peroxidation in pistachio seedlings by increasing the activity of antioxidant enzymes. According to our findings, ascorbate peroxidase and glutathione reductase play a major role in the antioxidative salicylic acid-induced defense against oxidative stress in pistachio. Taken together, our results show that the foliar application of SA could significantly enhance drought tolerance of pistachio seedlings through protecting photosynthetic apparatus, improving osmoregulation, and inducing the antioxidant defense system.

开心果（Pistacia vera  L.）是一种经济上重要的坚果作物，主要产于干旱和半干旱地区，容易受到干旱胁迫。考虑到水杨酸 (SA) 对开心果耐旱性的可能影响，研究了开心果幼苗在渐进干旱处理下叶面喷施水杨酸的几种生理和生化反应。SA 的应用增加了色素、叶绿素和类胡萝卜素的含量，并改善了脯氨酸和总可溶性碳水化合物等渗透物的积累，从而保护了光合装置和相对含水量。此外，SA 应用降低了干旱诱导的 H ₂ O ₂水平通过增加抗氧化酶的活性来促进开心果幼苗的脂质过氧化。根据我们的研究结果，抗坏血酸过氧化物酶和谷胱甘肽还原酶在抗氧化水杨酸诱导的开心果氧化应激防御中起主要作用。总之，我们的结果表明，叶面喷施 SA 可以通过保护光合器官、改善渗透调节和诱导抗氧化防御系统显着提高开心果幼苗的耐旱性。