Nickel Oxide Nanoparticles Improve Soybean Yield and Enhance Nitrogen Assimilation

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 NiSO4 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 Ni2+ supply for more extended periods than NiSO4, 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.

A study on nickel application methods for optimizing soybean growth

“…Compared with the seed and leaf application methods, studies on soil Ni fertilization are more advanced, with a range of growing environments, soil classes and soybean genotypes having been evaluated previously (Table 3 ). It has been reported in the literature that this method improves N metabolism in soybean plants 18 , 19 , 32 , 37 , 53 , 54 , 57 , as found in this study (Figs. 1 b,d, 3 and 4 ).…”

Co-exposure to tire wear particles and nickel inhibits mung bean yield by reducing nutrient uptake

“…These results align with the findings of Zhou et al , where NiO and NiSO 4 at 50 mg kg −1 had no impact on soybean root and shoot biomass and length but significantly increased the grain yield (39 and 19%) and grain weight (26 and 12%); however, NiSO 4 at 200 mg kg −1 significantly decreased the root length (∼25 and 33%), shoot length (∼19 and 25%), root biomass (∼17 and 28%), shoot biomass (∼17 and 34%), grain yield (∼25 and 23%) and grain weight (∼9 and 29%) of soybean. 17 Conversely, NiCl 2 at 50 mg L −1 decreased the seed yield, pods per plant, and grain weight of Cicer arietinum L. in soil by 13, 24, and 9%, respectively and by 21, 34, and 13% at 100 mg L −1 . 20 The increased toxicity of NiCl 2 may be associated with its rapid dissolution.…”

“…43 Zhou et al reported that the application of NiSO 4 increased soybean protein content at 50 mg kg −1 by 12%, while 200 mg kg −1 decreased the value by 20%. 17 Chen et al revealed that polystyrene microplastics (2 mg kg −1 ) enhanced the protein content in Vigna radiata L. by 3%, while levels were reduced by 3% at 4 mg kg −1 . Similarly, Pb (20–40 μM) decreased the protein content by 9% and 18%, respectively.…”

“…Under single analyte exposure, NiSO 4 at 50 mg kg −1 signicantly increased the root-shoot length, biomass, grain yield, grain weight, pods per plant and grains per pod of mung bean by 10,17,19,25,67,11,26 and 8%, respectively, as compared to untreated controls. However, at 100 mg kg −1 , NiSO 4 signicantly decreased the root length (30%), shoot length (24%), root biomass (30%), shoot biomass (26%), grain yield (77%), grain weight (24%), pods per plant (35%) and grains per pod (53%) compared to the controls (Fig.…”

“…There are published reports demonstrating Ni and TWP transport and accumulation in soil–plant systems, causing both physiological and biochemical effects. 16,17 TWPs at 80–150 mg g −1 increased the soil pH by 10–16% and soil respiration by 50–150%, respectively, subsequently impacting resident biota. 8,18 Leifheit et al reported that TWPs at 10 mg g −1 to 160 mg g −1 significantly reduced the root and shoot biomass of Allium porrum .…”