Harnessing nanoparticles to enhance crop production under drought stress: A quantitative meta-analysis

Drought stress (DS) severely threatens global food security, necessitating innovative solutions to enhance crop resilience. Nanoparticles (NPs) show potential for mitigating water scarcity and improving agricultural productivity; however, current research lacks systematic quantitative integration of NP-induced enhancement drought resilience mechanisms. We address this gap through a meta-analysis of 83 peer-reviewed investigations, employing effect size calculations ($\ln \mathrm{RR}$) to systematically quantify NP-induced improvements in crop drought resistance, while identifying critical determinants including NP types, application methods, and optimal concentrations. Our results demonstrate that NP applications under DS significantly enhanced crop growth and improved water use efficiency (WUE) by 28.3 % and 52.4 %, respectively, through osmotic regulation mediated by proline and soluble sugar accumulation. Furthermore, antioxidant enzyme activities were enhanced by 14.2–25.6 %, while H₂O₂ and MDA levels reduced by 39.1 % and 29.4 %, respectively. Foliar delivery at 100–150 mg L⁻¹ emerged as the optimal NP application strategy. ZnO NPs demonstrated the highest efficacy in enhancing drought resilience across crop types. We elucidated the physiological mechanisms through which NPs enhance drought tolerance and provide practical guidance for their agricultural application. Our findings support the development of more targeted and efficient crop management strategies in drought-prone regions.