Advanced characterization of biomineralization at plaque layer and inside rice roots amended with iron- and silica-enhanced biochar

Abstract

Application of iron (Fe)- and silica (Si)-enhanced biochar compound fertilisers (BCF) stimulates rice yield by increasing plant uptake of mineral nutrients. With alterations of the nutrient status in roots, element homeostasis (e.g., Fe) in the biochar-treated rice root was related to the formation of biominerals on the plaque layer and in the cortex of roots. However, the in situ characteristics of formed biominerals at the micron and sub-micron scale remain unknown. In this study, rice seedlings (Oryza sativa L.) were grown in paddy soil treated with BCF and conventional fertilizer, respectively, for 30 days. The biochar-induced changes in nutrient accumulation in roots, and the elemental composition, distribution and speciation of the biomineral composites formed in the biochar-treated roots at the micron and sub-micron scale, were investigated by a range of techniques. Results of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) showed that biochar treatment significantly increased concentrations of nutrients (e.g., Fe, Si, and P) inside the root. Raman mapping and vibrating sample magnetometry identified biochar particles and magnetic Fe nanoparticles associated with the roots. With Fe plaque formation, higher concentrations of FeOx− and FeOxH− anions on the root surface than the interior were detected by time-of-flight secondary ionization mass spectrometry (ToF-SIMS). Analysis of data from scanning electron microscopy energy-dispersive spectroscopy (SEM-EDS), and from scanning transmission electron microscopy (STEM) coupled with EDS or energy electron loss spectroscopy (EELS), determined that Fe(III) oxide nanoparticles were accumulated in the crystalline fraction of the plaque and were co-localized with Si and P on the root surface. Iron-rich nanoparticles (Fe–Si nanocomposites with mixed oxidation states of Fe and ferritin) in the root cortex were identified by using aberration-corrected STEM and in situ EELS analysis, confirming the biomineralization and storage of Fe in the rice root. The findings from this study highlight that the deposition of Fe-rich nanocomposites occurs with contrasting chemical speciation in the Fe plaque and cortex of the rice root. This provides an improved understanding of the element homeostasis in rice with biochar-mineral fertilization.

Development of Highly Efficient Heterogeneous Fe3O4‐Biochar Nanocomposite as Fenton‐like Catalysts for Degradation of Fast Green

“…However, there were 4 %, 6.2 %, and 2.5 % drops in degradation efficiency of FG against 8 mM solutions of the SO 4 −2 , CO 3 −2 , and Cl − anions, respectively. This drop in catalytic activity at higher concentrations of anions may be due to the scavenging of hydroxyl radicals by the anions [39,40] . The iron leaching experiments were performed after the reaction and the ferrous iron was found to be 3.92 ppm at 60 min.…”

“…This drop in catalytic activity at higher concentrations of anions may be due to the scavenging of hydroxyl radicals by the anions. [39,40] The iron leaching experiments were performed after the reaction and the ferrous iron was found to be 3.92 ppm at 60 min. The total dissolve iron was found to be 6.26 ppm at 60 min indicating the stability of the catalyst at acidic medium after the reaction.…”

Incorporation of engineered nanoparticles of biochar and fly ash against bacterial leaf spot of pepper

“…Moreover, the nano biochar due to its smaller particle size has high mobility in soils and helps to transport water 64 , 65 . Bashir et al 66 used composts and ZnO-nanoparticles to evaluate their effect on growth parameters like the dry weight of roots, shoots, husk, and kernels, plant height and spike length of the plant concerned 67 . Results obtained suggested a strong effect of used nanoparticles and compost material on growth promotion.…”

“…Results obtained suggested a strong effect of used nanoparticles and compost material on growth promotion. Furthermore, increased photosynthetic activity owing to nanoparticles inoculation, which reduces the effects of osmotic and oxidative stress, is well documented as the process increases the plant biomass 67 – 69 .…”

Dissolução de grãos minerais em colunas de solo

“…Trabalhos recentes utilizam SEM-EDS ou técnicas similares como FEM-EDS e SEM-EDX para caracterizar materiais orgânicos e inorgânicos, como biominerais de ferro e alumínio formados nas interfaces das raízes de grãos de arroz tratados com biochar, deposições de alumínio e silício na superfície de estruvitas em solos ou caracterizar produtos de tratamento hidrotermal de grãos de feldspato potássico (CHEN et al, 2021;GU et al, 2021;ZHAI et al, 2021).…”