Effects of cobalt oxide nanoparticles (Co3O4 NPs) on ion leakage, total phenol, antioxidant enzymes activities and cobalt accumulation in Brassica napus L.

Abstract

Interaction of nanoparticles (NPs) as a significant threat to ecosystems with biological processes of plants is very important. Here, the effects of cobalt oxide (Co3O4) NPs on some physio-biochemical characteristics of Brassica napus L. were investigated. The two-weeks seedlings were sprayed with different concentrations of Co3O4 NPs (0, 50, 100, 250, 500, 1000, 2000, and 4000 mg L-1). The results showed that this treatment significantly affected the fresh and dry weights, area, relative water content (RWC) and relative chlorophyll value (SPAD) of leaves. The highest reduction of growth and biomass indexes occurred at 4000 mg L-1 NPs. The content of H2O2 and electrolyte leakage (EL) increased respectively, after 100 and 250 mg L-1 of Co3O4 NPs and showed a maximum level at 4000 mg L-1. The activities of phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX) and superoxide dismutase (SOD) increased after 100 mg L-1 of Co3O4 NPs. However, tyrosine ammonia lyase (TAL) activity enhanced after 500 mg L-1. The catalase (CAT) activity and protein content decreased after 1000 mg L-1 of Co3O4 NPs. Application of concentrations higher than 500 mg L-1 of Co3O4 NPs induced polyphenol oxidase (PPO) activity but reduced glutathione reductase (GR). The activities of guaiacol peroxidase (GPX) and glutathione S-transferase (GST) increased at 250-1000 mg L-1 of Co3O4 NPs and then decreased. These results suggested that low concentrations of Co3O4 NPs induced a positive effect on growth parameters but high levels caused extensive oxidative damage and mediated defense responses by organization of phenolic compounds and antioxidative system.

Green Synthesis and Characterization of Cobalt Oxide Nanoparticles Using Psidium guajava Leaves Extracts and Their Photocatalytic and Biological Activities

“…The leaf extracts of P. guajava with high total phenolic and flavonoid content showed strong DPPH radical-scavenging activity because they exhibited a high hydrogen-donating capability to scavenge DPPH radicals. The current study had similar results to those reported by Jahani et al [ 62 ]. An increase in phenolic and flavonoid contents leads to their propensity to donate electrons to scavenge DPPH radicals, resulting in substantial DPPH radical scavenging activity, which explains that the DPPH radical-scavenging activity being related to the content of phenolic and flavonoid components in the extracts.…”

“…The nanoparticles were mixed with DPPH solution and kept for 60 min in a dark place. After 60 min of incubation, the reduction of DPPH radicals was monitored by UV-Spectrophotometer (Shimadzu UV 1800, Torrance, CA, USA) absorption at 517 nm [ 62 ]. The following formula was used to calculate the percentage inhibition of DPPH scavenges.…”

Phytosynthesis of Co3O4 Nanoparticles as the High Energy Storage Material of an Activated Carbon/Co3O4 Symmetric Supercapacitor Device with Excellent Cyclic Stability Based on a Na2SO4 Aqueous Electrolyte

“…It exhibited a peak of cobalt nanoparticles at 7 keV together with other small peaks. From the EDAX profile, a strong cobalt signal peak was confirmed …”

“…From the EDAX profile, a strong cobalt signal peak was confirmed. 53 Figure 4a,b depicts the particle shape of Co 3 O 4 -NPs, and the particles appeared in spherical shapes, 54 with some aggregation owing to the secondary metabolite complex surrounded by the particles as a coating layer. 55 The spacing between the lattice fringes (d) for the as-prepared nanoparticles is 0.28 nm (Figure 4c), which is compatible with the (311) plane of Co 3 O 4 -NPs, as seen in the SAED image.…”

Seed germination with titanium dioxide nanoparticles enhances water supply, reserve mobilization, oxidative stress and antioxidant enzyme activities in pea

“…Nano-TiO 2 (500 mg/L) decreased the membrane electrolyte leakage in barley germination seeds under salinity stress ( Karami and Sepehri, 2018 ). In previous work with cobalt nanoparticles, the content of electrolyte leakage increased after 250 mg L −1 of Co 3 O 4 NPs and showed a maximum level of 4000 mg L −1 ( Jahani et al, 2020 ). The variation in the solute leakage of pea seeds during germination after soaking with 50 mg.L −1 TiO 2 can be attributed to a disorder in nutrient supply.…”