Metallic Nanoparticle (TiO₂ and Fe₃O₄) Application Modifies Rhizosphere Phosphorus Availability and Uptake by Lactuca sativa

Abstract

Application of engineered nanoparticles (NPs) with respect to nutrient uptake in plants is not yet well understood. The impacts of TiO2 and Fe3O4 NPs on the availability of naturally soil-bound inorganic phosphorus (Pi) to plants were studied along with relevant parameters. For this purpose, Lactuca sativa (lettuce) was cultivated on the soil amended with TiO2 and Fe3O4 (0, 50, 100, 150, 200, and 250 mg kg(-1)) over a period of 90 days. Different techniques, such as scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Raman, and Fourier transform infrared spectroscopy (FTIR) were used to monitor translocation and understand the possible mechanisms for phosphorus (P) uptake. The trends for P accumulation were different for roots (TiO2 > Fe3O4 > control) and shoots (Fe3O4 > TiO2 > control). Cystine and methionine were detected in the rhizosphere in Raman spectra. Affinities of NPs to adsorb phosphate ions, modifications in P speciation, and NP stress in the rhizosphere had possibly contributed to enhanced root exudation and acidification. All of these changes led to improved P availability and uptake by the plants. These promising results can help to develop an innovative strategy for using NPs for improved nutrient management to ensure food security.

Elucidating the mechanisms for plant uptake and in-planta speciation of cerium in radish (Raphanus sativus L.) treated with cerium oxide nanoparticles

“…Among them, sugars, organic acids with low molecular weight (MW), and amino acid are the most common compounds in the exudates [26][27][28]. Consistent with CeO 2 NPs studies, previous research has shown that lettuce root exudates improved the solubilization of TiO 2 NPs and Fe 3 O 4 NPs in the rhizosphere [33]. Stegemeier et al also found that the root exudates of Alfalfa (Medicago sativa L.) could partially dissolve Ag 2 S-NPs, making them more bioavailable to plants [34].…”

Comparative Study on the Fungicidal Activity of Metallic MgO Nanoparticles and Macroscale MgO Against Soilborne Fungal Phytopathogens

“…It is believed that nMgO could potentially be applied as nanofertilizers for supplemental nutrients in agriculture without any toxicity to plants (Cai et al, 2018b). Moreover, recent studies have shown that, as a result of their unique properties, nanoparticles may influence lettuce (Lactuca sativa) metabolic activities, improving and mobilizing phosphorus availability and uptake in the rhizosphere (Zahra et al, 2015;Saharan et al, 2016). Most importantly, the phytotoxicity and biocompatibility of nanoparticles toward plants need to be investigated.…”

Effects of Manganese Nanoparticle Exposure on Nutrient Acquisition in Wheat (Triticum aestivum L.)

“…For example, nano-ZnO increased N and potassium (K) accumulation in sorghum, while the effect on phosphorus (P) accumulation was mixed [19]. However, P mobilization and accumulation from native soil was increased in lettuce by nano Fe 3 O 4 and TiO 2 [20]. Similarly, a nano-formulation of ZnO, CuO, and B 2 O 3 altered N, P, and K accumulation in soybean [21].…”