Synthesis and application of optimized ZnO nanoparticles for improving yield and Zn content of rice (Oryza sativa L.) grain

Abstract

Zinc is a crucial micronutrient and has great impact on growth, development, and yield of rice (Oryza sativa L.). Among various methods, application of zinc oxide (ZnO) nanoparticles (NPs) via roots or leaves can fulfill the Zn needs of plant. In the present research work, ZnO NPs were prepared through a cost-effective co-precipitation method and were compared with bulk ZnO for its effect on rice. Hexagonal wurtzite structure of synthesized ZnO NPs was confirmed with the help of X-ray diffraction analysis. Average crystallite size was found to be 20 nm. A pot experiment was conducted to evaluate the effect of ZnO NPs on growth, yield and nutritional quality of rice. The experiment comprised of ZnO NPs and bulk ZnO in three treatments as foliar spray, soil application, and root dipping along with control group having no zinc. Results revealed that foliar spray of ZnO NPs increased fresh biomass, grain yield, Zn content in grain and straw as compared to control. Soil application of ZnO NPs also increased husk and root zinc by 21% and 29%, respectively, compared to control. It was observed that soil applied ZnO NPs were mostly accumulated in roots or translocated to husk. Grain yield and grain Zn content was significantly increased by 11% and 28%, respectively, in case of foliar application of nano ZnO as compared to control group. It was concluded that foliar application of ZnO NPs can be used as commercial plant growth promotor and for biofortification purposes, specifically in rice.

Keywords:

• Bulk and nano ZnO
• rice
• agronomical parameters
• bio-fortification
• nanofertilizer

Acknowledgments

The authors acknowledge Muhammad Umair Mubarak and Muhammad Tayyab for helping to conduct pot experiment and data analysis. Furthermore, Dr. Abdur Rehman from Islamia University Bahawalur is also acknowledged for his valuable input to improve this article.

Additional information

Funding

This work was supported under the financial help of research grant NRPU Project No. 4602 to Dr Ayesha Younus funded by Higher Education Commission of Pakistan.