Salinity and drought are two major abiotic stresses that limit plant growth and productivity through their adverse effects on diverse physiological processes in plants, especially their photosynthetic capacity. Application of indigenous stress-tolerant plant growth-promoting rhizobacteria (PGPR) is among the eco-friendly strategies employed to ameliorate the harmful effects of salinity/drought stresses on plants. The present study was carried out to investigate the effects of stress-tolerant PGPR isolates on vegetative growth, nutritional, and photosynthetic parameters of pistachio (Pistacia vera L.) seedlings (cv. Badami-Riz–e-Zarand) under salinity and drought conditions. A factorial greenhouse experiment was conducted as a completely randomized design with three replications for 28 weeks in 2019. The treatments consisted of PGPR inoculations (control: non-inoculated, and inoculation with Staphylococcus sciuri, Zobellella denitrificans, and Arthrobacter endophyticus), three salinity levels (0, 1000 and 2000 mg NaCl kg⁻¹ soil), and three irrigation intervals (C: irrigated every two days; D1: four days and D2: six days). The results indicated that, under high levels of salinity and drought stresses (2000 mg NaCl kg⁻¹ soil + six-day irrigation intervals), separate inoculation of pistachio seedlings with Arthrobacter endophyticus, Zobellella denitrificans and Staphylococcus sciuri significantly enhanced the shoot and root dry weight, leaf area, leaf number, shoot and root K⁺ concentration and relative water content (RWC), which were accompanied by decreases in shoot and root Na⁺ concentrations. Moreover, the combined salinity and drought stresses had a greater effect on reducing total chlorophyll (TChl), carotenoids, chlorophyll fluorescence index (Fv/Fm), net photosynthetic rate (P_N), transpiration rate (E), stomatal conductance (Gs), intercellular CO₂ concentration (Ci), and water use efficiency (WUE), whereas application of the stress-tolerant PGPR isolates significantly increased these photosynthetic parameters compared to the non-inoculated seedlings at the corresponding stress levels. According to the results, the indigenous stress-tolerant PGPR isolates effectively improved the growth, physiological and photosynthetic parameters in pistachio seedlings subjected to salinity and drought stresses, which could be attributed to the local adaptation of the PGPR isolates as well as their plant growth-promoting properties that were unraveled in our in vitro studies, e.g. production of auxin, ACC-deaminase, siderophore, exopolysaccharides along with P/Zn solubilization activities.

盐度和干旱是两种主要的非生物胁迫，它们通过对植物的各种生理过程，尤其是光合能力的不利影响来限制植物的生长和生产力。应用本地耐胁迫植物促进生长的根际细菌 (PGPR) 是用于改善盐度/干旱胁迫对植物的有害影响的生态友好策略之一。本研究旨在研究耐胁迫 PGPR 分离株在盐度和干旱条件下对开心果（Pistacia vera L.）幼苗（cv. Badami-Riz-e-Zarand）的营养生长、营养和光合参数的影响. 在 2019 年进行了一项完全随机设计的析因温室试验，在 28 周内进行了 3 次重复。^-1土壤）和三个灌溉间隔（C：每两天灌溉一次；D1：四天，D2：六天）。结果表明，在高盐度和干旱胁迫下（2000 mg NaCl kg ^-1土壤 + 6 天灌溉间隔），开心果幼苗分别接种内生节杆菌、反硝化佐贝氏菌和金黄色葡萄球菌显着增强了地上部和根部的干燥。重量、叶面积、叶数、地上部和根部 K ⁺浓度和相对含水量 (RWC)，伴随着地上部和根部 Na ^{+ 的减少}浓度。此外，组合的盐度和干旱胁迫对减少总叶绿素（TChl），类胡萝卜素，叶绿素荧光指数（FV / FM），净光合速率（P更大的效果_Ñ），蒸腾速率（E），气孔导度（Gs） , 细胞间 CO ₂浓度 (Ci) 和水分利用效率 (WUE)，而在相应的胁迫水平下，与未接种的幼苗相比，应用耐胁迫 PGPR 分离株显着增加了这些光合参数。结果表明，本地耐胁迫的 PGPR 分离株有效地改善了受盐分和干旱胁迫的开心果幼苗的生长、生理和光合参数，这可能与 PGPR 分离株的局部适应性及其植物生长有关。在我们的体外研究中发现的促进特性，例如。生长素、ACC-脱氨酶、铁载体、胞外多糖以及 P/Zn 增溶活性的产生。