Mitigative effects and toxic risks of nano-zinc oxide on soybean under drought stress

作者：Xiyue Wang, Zirui Yi, Wei Jiang, Xin Li, Lijun LIU, Shoukun Dong · 发表于：Industrial Crops and Products · 年份：2026 · DOI：10.1016/j.indcrop.2025.122591 · 被引用次数：7 · 研究领域：Nanoparticles: synthesis and applications、Plant Stress Responses and Tolerance、Silicon Effects in Agriculture

Soybean production is frequently limited by drought stress. While zinc oxide nanoparticles (ZnO NPs) have shown potential in enhancing plant stress tolerance, their efficacy and toxicity under drought conditions remain poorly understood, especially in a genotype-dependent context. This study applied drought stress to two soybean varieties with significantly different drought resistance (drought-tolerant Heinong 87, HN87, and drought-sensitive Hefeng 55, HF55). The effects of foliar spraying with zinc oxide nanoparticles at different concentrations (50, 100, 200, and 400 mg/L) and application frequencies (1–6 times) were tested. Low concentrations of ZnO NPs (≤ 200 mg/L) significantly alleviated drought stress, enhancing root volume by up to 32.0 % in the tolerant variety and restoring stomatal conductance by 24.6 % in the sensitive variety. However, high concentration (400 mg/L) or excessive spray application (>3 times) induced significant toxicity, inhibiting root growth and reducing leaf fresh weight by more than 30.0 %. Low-dose ZnO NPs enhanced photosynthetic efficiency by 14.7–49.1 %, while high doses reduced it by 45.4–66.3 %, highlighting concentration-dependent effects. Regression modeling quantitatively defined the optimal spray frequency, with growth maxima occurring at or before 3 applications. Based on this model-derived optimum and the genotype-specific response patterns, we propose a precision application strategy: for drought-tolerant varieties, the model suppo...