FePO4 NPs Are an Efficient Nutritional Source for Plants: Combination of Nano-Material Properties and Metabolic Responses to Nutritional Deficiencies

Abstract

Phosphorous and iron are a macro- and micronutrient, respectively, whose low bioavailability can negatively affect crop productivity. There is ample evidence that the use of conventional P and Fe fertilizers has several environmental and economical disadvantages, but even though great expectations surround nanotechnology and its applications in the field of plant nutrition, little is known about the mechanisms underlying the uptake and use of these sub-micron particles (nanoparticles, NPs) by crop species. This work shows that cucumber and maize plants both use the nutrients borne by FePO 4 NPs more efficiently than those supplied as bulk. However, morpho-physiological parameters and nutrient content analyses reveal that while cucumber plants (a Strategy I species with regard to Fe acquisition) mainly use these NPs as a source of P, maize (a Strategy II species) uses them preferentially for Fe. TEM analyses of cucumber root specimens revealed no cell internalization of the NPs. On the other hand, electron-dense nanometric structures were evident in proximity of the root epidermal cell walls of the NP-treated plants, which after ESEM/EDAX analyses can be reasonably identified as iron-oxyhydroxide. It appears that the nutritional interaction between roots and NPs is strongly influenced by species-specific metabolic responses.

Phytate exudation by the roots of Pteris vittata can dissolve colloidal FePO4

“…However, there is a need more investigation for P. vittata and phyto siderophores role in FePO 4coll dissolution. Our results agreed with Sega et al (2020) who claimed that root exudation may dissolute the FePO 4 nano particles which release P and Fe. However, they did not mention which organic acid can dissolute the FePO 4 .…”

“…Colloidal P and Fe are frequently associated (Niyungeko et al, 2018;Fresne et al, 2021b, Jiang et al, 2015, and affect the uptake of P from colloids (Montalvo et al 2015); Zhang et al, 2021). In addition, Sega et al (2020) claimed that organic acid exudation may dissolve nano FePO 4 and release P for plant uptake; however, they did not identify which organic acids may be involved. However, the above mentioned studies did not mention the potential role of phytate exudation in dissolution of FePO 4coll .…”

Nanoforms of essential metals: from hormetic phytoeffects to agricultural potential

“…Interestingly, cucumber roots were not able to take up the nFe, possibly due to agglomeration. These comparative results clearly indicate that the nutrient utilization of roots exposed to FeSO 4 NPs is affected by species-specific metabolic responses ( Sega et al , 2020 ).…”

A novel FePO4 nanosized fertilizer is as efficient as triple superphosphate in sustaining the growth of cucumber plants

“…Differently, the higher initial P availability caused by TSP mainly depends on the soil P buffer capacity: the release of P in the soil solution triggered by the plant root induced modi cation of the chemical equilibrium between phosphates and the soil solid phases (Ehlert et al 2003). Globally, in terms of P fractionation in soil the main difference between TSP and NF is: for TSP it is in uenced by its dissolution rate and eventual salt precipitation due to the soil properties whereas for NF the P fractions depend more on the physico-chemical properties of the nanoparticles which could be solubilized by the root activity depending on the plant nutritional demand (Sega et al 2020;Khan et al 2022). This hypothesis could be supported by the results reported by Montalvo et al (2015) who showed in two strongly P sorbing soils a higher P uptake in roots of wheat plants fertilized with TSP as compared to plants fertilized with hydroxyapatite nanoparticles, a less soluble P form.…”