The challenging impact of drought to agricultural productivity requires the adoption of mitigation strategies with a better understanding of underlying mechanisms responsible for drought tolerance. The present study aimed at investigating the effects of sulfur-based fertilizers on mitigation of drought stress in sunflower. Sulfate-containing fertilizers, viz., ammonium sulfate, zinc sulfate, magnesium sulfate, potassium sulfate, and gypsum, were initially evaluated at two different rates (10 and 20 mg kg⁻¹ soil equivalent to 20 and 40 kg ha⁻¹, respectively) for nutrient uptake and growth-promoting traits in sunflower seedlings (cv. Hysun-33). The best performing fertilizer (gypsum) was then selected to evaluate the response of sunflower under drought stress imposed at flowering stage for three weeks (25–30% water holding capacity). Results indicated significant amelioration of drought stress with higher activity of photosynthetic apparatus, upregulation of antioxidative enzymes, and increased achene yield by gypsum application. In comparison to control, gypsum-treated plants (20 mg kg⁻¹ soil) exhibited higher water status (32%), leaf photosynthetic rate (29%), transpiration rate (67%), and stomatal conductance (118%) under drought stress. The antioxidant enzyme activities of catalase, guaiacol peroxidase, and superoxide dismutase were also increased by 67%, 62%, and 126%, respectively, resulting in higher achene yield (19%) under water-deficit conditions. This study indicates that the application of sulfur-based fertilizers (gypsum) can be used to induce drought tolerance and obtain high sunflower yields under drought stress, and furthermore, it is a cost-effective strategy resulting in high benefit–cost ratio with respect to no gypsum application.

干旱对农业生产力的挑战性影响需要采取缓解战略，更好地了解负责耐旱的潜在机制。本研究旨在研究硫基肥料对减轻向日葵干旱胁迫的影响。含硫酸盐的肥料，即硫酸铵、硫酸锌、硫酸镁、硫酸钾和石膏，最初以两种不同的比率进行评估（10 和 20 mg kg ^-1土壤相当于 20 和 40 kg ha ^-1，分别）用于向日葵幼苗（cv. Hysun-33）的养分吸收和生长促进性状。然后选择性能最好的肥料（石膏）来评估向日葵在开花期三周（25-30% 的持水量）干旱胁迫下的反应。结果表明，施用石膏可显着改善干旱胁迫，提高光合器官的活性，上调抗氧化酶，并增加瘦果产量。与对照相比，石膏处理的植物（20 mg kg ^-1土壤）在干旱胁迫下表现出较高的水分状况（32%）、叶片光合速率（29%）、蒸腾速率（67%）和气孔导度（118%）。过氧化氢酶、愈创木酚过氧化物酶和超氧化物歧化酶的抗氧化酶活性也分别提高了 67%、62% 和 126%，导致在缺水条件下瘦果产量更高（19%）。本研究表明，施用硫基肥料（石膏）可诱导耐旱性，在干旱胁迫下获得较高的向日葵产量，此外，它是一种具有成本效益的策略，可实现高效益成本比。没有石膏应用。