Nickel Oxide Nanoparticles Improve Soybean Yield and Enhance Nitrogen Assimilation
Pingfan Zhou, Yaqi Jiang, Muhammad Adeel, Noman Shakoor, Weichen Zhao, Yanwanjing Liu, Yuanbo Li, Mingshu Li, Imran Azeem, Yukui Rui, Zhiqiang Tan, Jason C. White, Zhiling Guo, Iseult Lynch, Peng Zhang
Abstract
Nickel (Ni) is a trace element beneficial for plant growth and development and could improve crop yield by stimulating urea decomposition and nitrogen-fixing enzyme activity. A full life cycle study was conducted to compare the long-term effects of soil-applied NiO nanoparticles (n-NiO), NiO bulk (b-NiO), and NiSO 4 at 10–200 mg kg –1 on plant growth and nutritional content of soybean. n-NiO at 50 mg kg –1 significantly promoted the seed yield by 39%. Only 50 mg kg –1 n-NiO promoted total fatty acid content and starch content by 28 and 19%, respectively. The increased yield and nutrition could be attributed to the regulatory effects of n-NiO, including photosynthesis, mineral homeostasis, phytohormone, and nitrogen metabolism. Furthermore, n-NiO maintained a Ni 2+ supply for more extended periods than NiSO 4, reducing potential phytotoxicity concerns. Single-particle inductively coupled plasma mass spectrometry (sp-ICP-MS) for the first time confirmed that the majority of the Ni in seeds is in ionic form, with only 28–34% as n-NiO. These findings deepen our understanding of the potential of nanoscale and non-nanoscale Ni to accumulate and translocate in soybean, as well as the long-term fate of these materials in agricultural soils as a strategy for nanoenabled agriculture.