The distribution of Rare Earth Elements discriminates the growth substrate of Vitis vinifera L

A systematic review and meta-analysis on the root effects and toxic mechanisms of rare earth elements

Rare earth elements (REEs) have attracted much attention because of their unique physical and chemical properties. The root system is the plant organ most directly in contact with REEs, and it is critical to understand the mechanisms of interaction between the two. This paper investigates the effects of REEs on plant enrichment and fractionation, as well as on various developmental and toxicity indices of the root system. REEs are more likely to be deposited on the root surface under the influence of root secretion. The complexation between the two affects the uptake and fractionation of REEs and the altered pattern of root secretion. The toxicity mechanisms of REEs on plant root cells were lied in: (1) REEs generate reactive oxygen species after entering the plant, leading to oxidative stress and damage to plant cells; (2) REEs with higher charge-to-volume ratios compete for organic ligands with or displace Ca2+, further disrupting the normal function of plant root cells. It was shown that the sensitivity of inter-root microorganisms to REEs varied depending on the content and physicochemical properties of REEs. The paper also concluded with a meta-analysis of phytotoxicity induced by REEs, which showed that REEs affect plant physiological parameters. REEs, as a source of oxidative stress, triggered lipid peroxidation damage in plants and enhanced the activity of antioxidant enzymes, thus revealing the significant toxicity of REEs to plants. The phytotoxic effects of REEs increased with time and concentration. These results help to elucidate the ecotoxicology of rare earth-induced phytotoxicity.

Rare earth elements as a tool to study the foliar nutrient uptake phenomenon under ambient and elevated atmospheric CO2 concentration

The ability of plants to uptake nutrients from mineral dust lying on their foliage may prove to be an important mechanism by which plants will cope with increasing CO2 levels in the atmosphere. This mechanism had only recently been reported and was shown to compensate for the projected dilution in plants ionome. However, this phenomenon has yet to be thoroughly studied, particularly in terms of the expected trends under different dust types and varying atmospheric CO2 concentrations, as projected by the IPCC. We treated plants grown under ambient (415 ppm) and elevated CO2 (850 ppm) conditions with either desert dust, volcanic ash, and fire ash analogues by applying it solely on plant foliage and studied their Rare Earth Elements concentrations and patterns. The Rare Earth Elements compositions of the treated plants originated from the dust application, and their incorporation into the plants led to a significant increase in plants vitality, evident in increased photosynthetic activity and biomass. Two trends in the foliar nutrient uptake mechanism were revealed by the Rare Earth Elements, one is that different treatments affected the plant in decreasing order volcanic ash > desert dust > fire ash. The second trend is that foliar intake becomes more significant under elevated CO2, an observation not previously seen. This testifies that the use of Rare Earth Elements in the study of foliar nutrient uptake, and other biological mechanisms is fundamental, and that foliar pathways of nutrient uptake will indeed become more dominant with increasing CO2 under expected atmospheric changes.

The Pattern of Rare Earth Elements Like a Possible Helpful Tool in Traceability and Geographical Characterization of the Soil-Olive System (Olea europaea L.)

The identification of a product, with its geographical origin, is a guaranty of the value of the foodstuff and protection from potential fraud. Extra virgin olive oil is produced or marketed as a single variety or a blend of two or more cultivars, often of different geographic origins. Therefore, to study a possible link between the soil and olive oil, we accounted crucial to analyse the behaviour of olive of different cultivars. We studied Rare Earth Elements (REE) amounts and their relationship to trace their distribution from soil to the olive pulp (Olea europea L.). The results obtained pointed out that the different cultivars of Olea did not drive significant differences in reciprocal ratios of REE in the uptake from the soil up to olive (except for Eu). However soil-plant Rare Earth relationships depend exclusively on the soil REE composition. This method can be the starting point to enforcing the laws, in fact, it is important to develop analytical methods to measure the authenticity of the samples, and to verify the geographical origin even when olive oil is blended.