ABSTRACT Soil microorganisms play an important role in enhancing soil fertility and plant health. Nitroxin is a bio-fertilizer that is a combination of Azospirilium and Azotobacter rhizobacteria. Arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria can enhance biotic and abiotic stress tolerance in plants, whereas little is known regarding their roles in sorghum (Sorghum bicolor L.) growth under drought stress conditions. Therefore, this experiment was conducted to investigate the inoculation of grain sorghum with the bio-fertilizers of Nitroxin and Glomus mosseae effects on some physiological and biochemical traits and yield of grain sorghum under drought stress conditions in the region of Saravan, Iran, in 2017 and 2018. The results of this experiment showed that severe and moderate drought stress conditions decreased the amounts of grain protein percentage, auxin (IAA) content, root colonization, grain yield, and protein yield of grain, whereas grain starch percentage, the activity of catalase (CAT), peroxidase (POD) and ascorbate peroxidase (APX) enzymes and content of total carotenoid, total anthocyanin, total flavonoid, electrolyte leakage, and malondialdehyde (MDA) were increased. Inoculation of sorghum plants with bio-fertilizers improved these traits (except starch content, electrolyte leakage, and MDA) under drought stress conditions as well as non-stress conditions. As a result, grain yield and protein yield of sorghum decreased by 43.77 and 43.99%, respectively, under severe drought stress conditions but co-inoculation with Nitroxin and AMF under severe drought stress conditions increased grain yield and protein yield of sorghum by 27 and 19.63%, respectively, compared to non-application of these bio-fertilizers. Thus, Nitroxin and AMF can be recommended for profitable sorghum production under drought stress conditions.

中文翻译：

---

氮素和丛枝菌根真菌通过改善生理生化特性缓解干旱胁迫对双色高粱产量的负面影响

摘要 土壤微生物在提高土壤肥力和植物健康方面发挥着重要作用。Nitroxin 是一种生物肥料，是固氮螺菌和根际固氮菌的混合物。丛枝菌根真菌 (AMF) 和促进植物生长的根际细菌可以增强植物的生物和非生物胁迫耐受性，而关于它们在干旱胁迫条件下对高粱 (Sorghum bicolor L.) 生长的作用知之甚少。因此，本试验旨在研究 2017 年在伊朗沙拉湾地区，在干旱胁迫条件下，用 Nitroxin 和 Glomus mosseae 生物肥料接种高粱对高粱某些生理生化性状和产量的影响。 2018 年。本试验结果表明，重度和中度干旱胁迫条件降低了籽粒蛋白质含量、生长素（IAA）含量、根系定植量、籽粒产量和籽粒蛋白质产量，而籽粒淀粉含量、过氧化氢酶（CAT )、过氧化物酶 (POD) 和抗坏血酸过氧化物酶 (APX) 酶以及总类胡萝卜素、总花青素、总黄酮、电解质泄漏和丙二醛 (MDA) 的含量增加。在干旱胁迫条件和非胁迫条件下，用生物肥料接种高粱植物改善了这些性状（淀粉含量、电解质渗漏和 MDA 除外）。结果，高粱的籽粒产量和蛋白质产量分别下降了 43.77% 和 43.99%，在严重干旱胁迫条件下，但与不施用这些生物肥料相比，在严重干旱胁迫条件下与氮氧化合物和 AMF 共同接种使高粱的谷物产量和蛋白质产量分别提高了 27% 和 19.63%。因此，在干旱胁迫条件下，可以推荐氮氧化合物和 AMF 用于有利可图的高粱生产。