Agronomic Zn biofortification through nano ZnO application enhanced growth, photosystem efficiency, Zn and P nutrition in maize

ABSTRACT

Zinc-oxide nanoparticles (ZnO-NP) effect on crop physiology and zinc recovery remains poorly studied for acidic-sandy soils. To address this, greenhouse pot (plastic-pots, 6 kg soil, maize) experiments with ZnO-NP (50, 100, 150, 200 mg kg⁻¹) applied via different methods (soil-drench, seed-coating and foliar-spray) was conducted in a 60 days study. Results revealed that ZnO-NP via seed-coating (100 mg kg⁻¹) and soil-drench (150 mg kg⁻¹) enhanced shoot and total P uptake, while ZnO-NPs (foliar) (50 mg kg⁻¹) enhanced maize growth (6–11%), with agronomic and physiological improvements ultimately resulted in greater biomass (16–20%), Zn agronomic efficiency and uptake. Compared to ZnSO₄ treatment and the control, seed-coating with 100 mg kg⁻¹ ZnO-NP increased leaf chlorophyll and pigment content by 12–127%. Principal component analysis revealed a close association among growth traits, plant pigments, fluorescence parameters, total Zn and P concentration, and uptake with total biomass as influenced by ZnO-NPs. Thus, compared to conventional ZnSO₄ and higher dosages of ZnO-NPs, foliar-spray of ZnO-NP at 50 mg kg⁻¹, seed-coating at 100 mg kg⁻¹, or soil-drench at 150 mg kg⁻¹ increased maize biochemical characteristics, growth, biomass, and Zn agronomic efficiency. These elucidate important implications of ZnO-NP application for increasing plant development and Zn biofortification in acidic-sandy soils.

KEYWORDS:

• Chlorophyll
• photosystem efficiency
• photosynthesis
• ZnO nanoparticles
• Zn nutrition

Acknowledgments

The researchers thank the University of Florida for conducting this study and the Higher Education Commission (HEC) of Pakistan for funding Dr. Ahmad’s postdoctoral research scholar visit to the University of Florida in the United States. The authors also acknowledge the support of Mr. Brian Cain in the sample analysis.

Disclosure statement

The authors declare no financial or personal interests that may affect the research presented in this publication.

Supplemental data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/03650340.2023.2231350