Uptake Of Trace Elements Research Articles

Stability of metal ion complexes with the synthetic phytosiderophore proline-2'-deoxymugineic acid.

Adequate micronutrient concentrations in crops are essential for human health and agricultural productivity. However, 30% of plants growing on cultivated soils worldwide are deficient in iron (Fe). Because of low micronutrient bioavailability, graminaceous plants have evolved to exude small molecules, called phytosiderophores, into the soil environment, which strongly complex and promote uptake of trace elements. The development of a synthetic phytosiderophore, proline-2'-deoxymugeneic acid (PDMA), has been shown to promote Fe uptake in rice plants; however, its binding capabilities with other metals, which may impact the ability to promote the uptake of Fe and other trace nutrient metals commonly found in soils, remain unknown. We conducted spectrophotometric titrations to determine the stability constants (logK) of PDMA complexes with Mn(II), Co(II), Cu(II), Ni(II), and Zn(II). We determined that PDMA complex stability constants correlated with: (1) the hydrolysis constants of metal ions (logKOH) in complexes; (2) the ionic potential of complexed metals; and (3) the corresponding complex stability constants of other mugineic acid type phytosiderophores, as well as the trishydroxamate microbial siderophore DFOB. These correlations demonstrate the potential, and limitations, on our ability to predict the stability of phytosiderophore complexes with metal ions with different physicochemical properties and with potentially different coordination structures.

Towards a circular economy - Repurposing side streams from the potato processing industry by Chlorella vulgaris

Common wastewater treatment strategies in the food industry do not include efficient remediation strategies for nitrogen, phosphorous and organic carbon. Incorporating microalgae in water treatment plants is rising in popularity because of their high nutrient and trace element uptake driven by light. In this study, four different side streams from an Austrian potato processing company have been screened for their applicability of microalgal cultivation. The side streams were assessed for Chlorella vulgaris growth and their requirement of any additional pretreatment or media supplementation. One side stream specifically, called blanching water II, a stream generated by boiling the potatoes for ease of peeling, turned out very useful to cultivate Chlorella vulgaris and concomitantly remedy the wastewater. Compared to a state-of-the-art cultivation in BG11, cultivating Chlorella vulgaris in blanching water II led to a 45 % increase in specific growth rate of 1.29 day−1 and a 48% increase in biomass productivity to 294.6 mg/L/day, while all nitrogen and phosphate present in the side stream were metabolized. Overall, the results demonstrate that the water remediation process for blanching water II shows vast potential in regard to water purification and waste to value approaches.

Uptake of zinc from the soil to the wheat grain: Nonlinear process prediction based on artificial neural network and geochemical data

Trace elements in plants primarily derive from soils, subsequently influencing human health through the food chain. Therefore, it is essential to understand the relationship of trace elements between plants and soils. Since trace elements from soils absorbed by plants is a nonlinear process, traditional multiple linear regression (MLR) models failed to provide accurate predictions. Zinc (Zn) was chosen as the objective element in this case. Using soil geochemical data, artificial neural networks (ANN) were utilized to develop predictive models that accurately estimated Zn content within wheat grains. A total of 4036 topsoil samples and 73 paired rhizosphere soil-wheat samples were collected for the simulation study. Through Pearson correlation analysis, the total content of elements (TCEs) of Fe, Mn, Zn, and P, as well as the available content of elements (ACEs) of B, Mo, N, and Fe, were significantly correlated with the Zn bioaccumulation factor (BAF). Upon comparison, ANN models outperformed MLR models in terms of prediction accuracy. Notably, the predictive performance using ACEs as input factors was better than that using TCEs. To improve the accuracy, a two-step model was established through multiple testing. Firstly, ACEs in the soil were predicted using TCEs and properties of the rhizosphere soil as input factors. Secondly, the Zn BAF in grains was predicted using ACE as input factors. Consequently, the content of Zn in wheat grains corresponding to 4036 topsoil samples was predicted. Results showed that 85.69 % of the land was suitable for cultivating Zn-rich wheat. This finding offers a more accurate method to predict the uptake of trace elements from soils to grains, which helps to warn about abnormal levels in grains and prevent potential health risks.

Synergistic effect by Sorghum bicolor L., citric acid, biochar, and vermiwash amendment for the remediation of a mine-contaminated soil.

Phytoremediation is an in situ remediation and eco-friendly technique employing accumulator plant species to remove trace elements (TEs) from contaminated sites. Moreover, it has been demonstrated that both natural and synthetic amendments can enhance trace elements (TEs) phytoremediation from polluted soils through bioenergy crops. This work assessed the synergistic impact of two tested biochar (BC) from data palm (B1) and Prosopis (B2) (1.5%/ kg), citric acid (CA, 1.5 mmol/kg) and vermiwash (VW, 20 ml/kg) to enhance the remediation of tested TEs (Mn, Zn, Cd, Pb, Ni, Cu, and Fe) from Mahad AD'Dahab mine-contaminated soil by sorghum (Sorghum bicolor L.). The BC and CA amendments alone and combined with VW significantly augmented the proliferation and survival of sorghum grown in mine-contaminated soil. Considering the individual and combined applications of VW and BC, the influence on plant growth followed this order: K < VW < B2 < B1 < B1 + VW < B2 + VW < CA < CA + VW. Applying tested BC/CA and VW significantly increased chlorophyll compared to unamended soil. The outcomes revealed a substantial elevation in TE absorption in both shoot and root (p ≤ 0.05) with all tested treatments compared to the untreated soil (K). The combined application of CA and VW resulted in the most significant TE uptake of TEs at both the root and the shoot. Furthermore, adding CA or VW as a foliar spray enhanced the bioaccumulation factor (BCF) and translocation factor (TF) of studied metals. The combined addition of CA and foliar spraying of VW was more effective than the sole addition of CA or VW. Such increase reached 20.0%, 15.6%, 19.4%, 14.3%, 14.0%, and 25.6% of TF, and 13.7%, 11.9%, 8.3%, 20.9%, 20.5%,18.7%, and 19.8% of BCE for Cd, Cu, Fe, Mn, Ni, Pb, and Zn, respectively. This study highlights the efficiency of combining CA/BC with VW as a more viable option for remediating mine-contaminated soil than individual amendments. However, future research should prioritize long-term field trials to assess the efficiency of using citric acid and vermiwash for restoring contaminated mining soils.

Silicon nanoparticles vs trace elements toxicity: Modus operandi and its omics bases.

Phytotoxicity of trace elements (commonly misunderstood as 'heavy metals') includes impairment of functional groups of enzymes, photo-assembly, redox homeostasis, and nutrient status in higher plants. Silicon nanoparticles (SiNPs) can ameliorate trace element toxicity. We discuss SiNPs response against several essential (such as Cu, Ni, Mn, Mo, and Zn) and non-essential (including Cd, Pb, Hg, Al, Cr, Sb, Se, and As) trace elements. SiNPs hinder root uptake and transport of trace elements as the first line of defence. SiNPs charge plant antioxidant defence against trace elements-induced oxidative stress. The enrolment of SiNPs in gene expressions was also noticed on many occasions. These genes are associated with several anatomical and physiological phenomena, such as cell wall composition, photosynthesis, and metal uptake and transport. On this note, we dedicate the later sections of this review to support an enhanced understanding of SiNPs influence on the metabolomic, proteomic, and genomic profile of plants under trace elements toxicity.

Soil Amendment and Tillage to Reduce Phosphorus Loss in Coastal Western Australia

Phosphorus (P) runoff is a major factor contributing to water quality decline in waterways and waterbodies of coastal Western Australia (WA). Soils with naturally low P retention or those with increased P saturation from P application have higher risk of P loss via leaching or runoff. Substantial research has been carried out to minimise P loss via leaching and runoff through modifications of soil P retention capacity. We review literature of P retentive soil amendments, natural clays and tillage of soil to lift clay to the surface to increase P retention and reduce P loss from poorly retentive sandy soils and P stratified soils, and which have been tested for efficacy and safety. This review includes published research, previously unpublished trial data, research in unpublished reports and published research in limited circulation with particular emphasis on the Swan Coastal Plain due to unabated P loss and limited uptake of soil amendment in the region to combat it. Key findings are that amending leaching sands with bauxite residue from alumina refining, neutralised used acid (NUA from mineral sands processing) and clay, as well as tillage or mixing of P stratified soils have been shown to be very effective at reducing P loss. Increases in plant productivity have been found, depending on conditions such as soil pH and soil test P. For the materials tested, soil amendment did not lead to undue uptake of trace elements or concerning levels of radiation. Trials of NUA have shown Mn is close to acceptable limits or slightly exceeds them and is the subject of further research to determine application rates and field conditions required to minimise Mn or other contamination. The P retentive effect of soil tillage is restricted to soils with high P levels in the soil surface and higher P retention below the surface, reachable by soil tillage equipment.

Ocean acidification impact on the uptake of trace elements by mussels and their biochemical effects

This study delves into the intricate interplay between ocean acidification (OA), metal bioaccumulation, and cellular responses using mussels (Mytilus galloprovincialis) as bioindicators. For this purpose, environmentally realistic concentrations of isotopically labelled metals (Cd, Cu, Ag, Ce) were added to investigate whether the OA increase would modify metal bioaccumulation and induce adverse effects at the cellular level. The study reveals that while certain elements like Cd and Ag might remain unaffected by OA, the bioavailability of Cu and Ce could potentially escalate, leading to amplified accumulation in marine organisms. The present findings highlight a significant rise in Ce concentrations within different mussel organs under elevated pCO2 conditions, accompanied by an increased isotopic fractionation of Ce (140/142Ce), suggesting a heightened potential for metal accumulation under OA. The results suggested that OA influenced metal accumulation in the gills of mussels. Conversely, metal accumulation in the digestive gland was unaffected by OA. The exposure to both trace metals and OA affects the biochemical responses of M. galloprovincialis, leading to increased metabolic capacity, changes in energy reserves, and alterations in oxidative stress markers, but the specific effects on other biomarkers (e.g., lipid peroxidation, some enzymatic responses or acetylcholinesterase activity) were not uniform, suggesting complex interactions between the stressors and the biochemical pathways in the mussels.

PGPR-driven phytoremediation and physiobiochemical response of Miscanthus × giganteus to stress induced by the trace elements.

The effect of inoculation of Miscanthus × giganteus Greef et Deu by the plant growth promoting rhizobacteria (PGPRs) to the phytoremediation process and physio-biochemical plant's parameters was investigated in soil contaminated with the trace elements (TEs) from the Tekeli mining complex, Kazakhstan. Yeast Trichosporon sp. CA1, strains Rhizobium sp. Zn1-1, Shinella sp. Zn5-6, and Pseudomonas sp. CHA1-4, resistant to Zn and Pb, were isolated from the rhizosphere of M × g when the plant was cultivated in the same contaminated soil. Results illustrated that inoculation improved M × g adaptability to TEs toxicity by increasing the tolerance index to 2.9. The treatment enhanced the aboveground biomass yield by up to 163%, root biomass by up to 240%, chlorophyll content by up to 30%, and Chla/b ratio by up to 21%. Through M × g active growth and development, the peak activity of antioxidant enzymes was observed: activity of superoxide dismutase and glutathione reductase was induced, while the activity of catalase and ascorbate peroxidase was inhibited. Based on bioconcentration and translocation factors it was revealed that PGPRs selectively increased the uptake of TEs or stabilised them in the M × g rhizosphere. Inoculation with PGPRs increased the stabilization of Pb, V, Cr, Co, Ni, Cu, Cd, As, and Ba in the soil and plant tissues. Further research should focus on ex situ experiments using isolated PGPRs.

What dead seaweeds can tell us about metal uptake and their application to control marine pollution

The mechanisms of trace element uptake by seaweeds are still unknown, despite being key to understand the impact of pollution in coastal environments. This knowledge gap, in addition to the lack of standardization, have also hindered the use of seaweeds to monitor seawater pollution. To address these shortcomings, we tested the use of devitalization as a pre-exposure treatment for brown seaweed transplants, and we compared devitalized and fresh transplants to gain some insights into the mechanisms of element uptake. We exposed four types of Fucus vesiculosus transplants in 6 sites for 4, 8 and 20 days: fresh and devitalized (dried or boiled) algal segments held in mesh bags, and whole algal thalli imitating natural conditions. We then determined he concentrations of 11 trace elements in the algal tissues. The element concentrations were highest in the devitalized transplants, but the material lost consistency and weight throughout the exposure period, limiting their use to short periods. We proposed several factors that may contribute to the different accumulation patterns between treatments, and examined the implications for the uptake mechanisms, revealing that two of the most important are surface adsorption of sediment particles and chemical bounds to extracellular components.

Tracing nickel smelter emissions using European honey bees

This study investigated trace element contamination in honey bees inhabiting urban areas around the South Pacific's largest and longest operating nickel smelter in Nouméa, New Caledonia. There remains a paucity of research on the environmental impact of nickel smelting, and to date, there has been no assessment of its effects on the popular practice of beekeeping, or whether honey bees are a suitable tracer for nickel smelting emissions. Honey bees and honey were sampled from 15 hives across Nouméa to ascertain linkages between nickel smelter emissions, environmental contamination, and trace element uptake by bees. Comparison of washed and unwashed bees revealed no significant difference in trace element concentrations, indicating trace elements bioaccumulate within the internal tissues of bees over time. Accordingly, trace element concentrations were higher in dead bees than those that were sampled live, with smelter related elements chromium, cobalt and nickel being significantly different at p < 0.05. Except for boron, trace element concentrations were consistently higher in bees than in honey, suggesting that the transfer of trace elements from bees during honey production is negligible. Elevated concentrations of potentially toxic trace elements including cobalt, chromium and nickel in bees declined with distance from smelting operations (Spearman's Rho, p < 0.05), indicating the relationship between environmental contamination and the uptake of trace elements by bees. The findings of this study emphasise potential environmental and human health risks associated with trace element contamination from nickel smelting operations and affirm the use of honey bees as a biomonitor of potentially harmful nickel smelting emissions.

A machine learning method for distinguishing detrital zircon provenance

Zircon geochemistry provides a sensitive monitor of its parental magma composition. However, due to the complexity of the uptake of trace elements during zircon growth, identifying source magmas remains challenging, particularly for detrital grains whose petrological context is lost. We use a machine learning-based approach to explore the classifiers for zircon provenance, based on 3794 published, high-quality zircon trace element analyses compiled from I-, S-, and A-type granites. Three supervised machine learning algorithms, namely, Support Vector Machine (SVM), Random Forest (RF), and Multilayer Perceptron (MLP) were used and trained with 11 features, including 7 trace elements (Ce, Eu, Ho, Nb, Ta, Th, and U) and 4 derived trace element ratios (Th/U, U/Yb, Ce/Ce*, and Eu/Eu*). Our results show that all three trained machine learning methods perform very well with accuracy varying from 0.86 to 0.89, and that input–output relationships captured by different ML methods are nearly consistent and can be explained by the known petrological processes. The application of our trained machine learning classifiers to detrital zircon studies will enhance the interpretability of zircon assemblages of different origins. It also helps develop interpretations, approaches, and tools that will benefit, for example, the study of continental crust evolution and mineral exploration.

The interference of marine accidental and persistent petroleum hydrocarbons pollution on primary biomass and trace elements sink

More than 80 % of the primary biomass in marine environments is provided by phytoplankton. The primary mechanism in the trace element sink is the absorption of trace elements by phytoplankton. Because of their difficult degradability and bioaccumulation, petroleum hydrocarbons are one of the most significant and priority organic contaminants in the marine environment. This study chose Chlorella pyrenoidosa as the model alga to be exposed to short and medium-term petroleum hydrocarbons. The ecological risk of accidental and persistent petroleum hydrocarbon contamination was thoroughly assessed. The interaction and intergenerational transmission of phytoplankton physiological markers and trace element absorption were explored to reflect the change in primary biomass and trace element sink. C. pyrenoidosa could produce a large number of reactive oxygen species stimulated by the concentration and exposure time of pollutants, which activated their antioxidant activity (superoxide dismutase (SOD) activity, β-carotene synthesis, antioxidant trace elements uptake) and peroxides production (hydroxyl radicals and malondialdehyde). The influence of the growth phase on SOD activity, copper absorption, and manganese adsorption in both persistent and accidental pollution was significant (p < 0.05, F > Fα). Adsorption of manganese and selenium positively connected with SOD, malondialdehyde, and Chlorophyl-a (p < 0.01). These findings convincingly indicate that petroleum hydrocarbon contamination can interfere with primary biomass and trace element sinks.

Trace Element Content in Soils with Nitrogen Fertilisation and Humic Acids Addition

Application of mineral fertilisers can entail an increase in trace element content in the soil. In consequence, their elevated uptake by plants and transfer to further trophic chain links may occur. The aim of the research reported here was to determine the usefulness of the tested organic materials, such as humic acids, for reduction of the content of trace elements in two soils fertilised with excessive doses of nitrogen fertilisers. Soil type had a considerable effect on soil trace element content. The content of most trace elements (cadmium, lead, chromium, cobalt, nickel, manganese, and iron) was higher in loamy sand than in sand. Among the tested fertilisers, a higher content of most soil trace elements was found after the application of ammonium nitrate. Urea fertilisation led to a decrease in the content of cadmium, chromium, copper, and zinc in both soils; cobalt, manganese, and nickel in sand; and an increase in concentration of cobalt and manganese in loamy sand, relative to the subjects fertilised with ammonium nitrate. Urea ammonium nitrate solution (UAN) decreased the content of chromium, cadmium, copper, nickel, and zinc in both soils; lead in the sand; and cobalt in the loamy sand, while raising the content of lead in the loamy sand, relative to the subjects fertilised with ammonium nitrate. The impact of urea and UAN on the remaining trace element content in the soils was comparable to that effected by ammonium nitrate. The effect of humic acids on trace element content in the soil tended to be beneficial, as they reduced the soil concentrations of these elements compared to the control subject (without their application). However, it should be emphasised that their effect depended on nitrogen fertiliser form and soil type. Humic acids can effectively reduce the uptake of trace elements by some plant species.

The effect of contrasting biosolids application strategies on soil quality

PurposeIncorporating biosolids into the soil improves plant yield compared with surface application, but it can result in the increased uptake of trace elements. However, there is a lack of knowledge about how different types of biosolids applications affect soil quality. We aimed to determine the effect of the type and rate of biosolids application on soil quality and the mobility of contaminants.MethodsSoil quality was determined by soil fertility (inorganic N, exchangeable P, Mg, Ca, K), exchangeable trace and non-essential elements (Al, Mn, Zn, Cu and Cd) and biological activity (dehydrogenase activity). We measured the properties of soil pore water, bulk soil and rhizosphere in a pot and a rhizobox experiment, with increasing concentration of biosolids (equiv. 16 t ha− 1, 48 t ha− 1 and 145 t ha− 1 dry weight), applied on the surface, incorporated to 25 cm, or incorporated into a patch.Results and discussionThe incorporation of biosolids into the soil increased the exchangeable Zn, Cu, Cr, Ni and Cd, compared with surface application. The surface application of biosolids increased the inorganic N in the soil compared with biosolids incorporation (680 mg kg− 1 vs. 380 mg kg− 1), and decreased soil pH by 1.1 units. This aligned with solubilisation of Al (43 mg kg− 1 vs. 6 mg kg− 1) and Mn (43 mg kg− 1 vs. 33 mg kg− 1) and explains the decreased microbial activity in the soil compared with the unamended soil. Incorporating biosolids in the soil increased the biological activity, likely due to biosolids-borne microbes. The root systems significantly increased microbial activity, pH, and the concentration of NH4+, NO3−, and exchangeable P, S, Mg, Na, Zn, Cu and Ni, and significantly decreased exchangeable concentration of Mn and Fe.

Use of Me/Ca ratios as proxies for coastal marine conditions in ostracod shells of Sinocytheridea impressa and Neomonoceratina delicata

Paleo-reconstructions using element to calcium ratios (Me/Ca) of marine ostracods were usually focused on Mg/Ca and Sr/Ca, whereas paleo-environmental applications using other ostracod Me/Ca including Na/Ca, Ba/Ca, Mn/Ca, Zn/Ca, Ni/Ca, Cd/Ca, Cu/Ca and Cr/Ca have been rather limited due to the lack of a general understanding of the control of physicochemical marine variables on trace-elements uptake. Ba/Ca and Na/Ca were linked to temperature, while Mn/Ca was suggested to be an indicator of redox conditions and used to track oxide contamination in marine shells. The potential of other ostracod ratios as environmental proxies has rarely been investigated. Here, we study the empirical relations between seawater physicochemical variables and several Me/Ca of ostracod shells in shallow marine waters. Our results suggest that shallow sea parameters related to the control of metal concentrations in seawater and sediments such as suspended solids, salinity, electrochemical potential and total carbon are correlated to Me/Ca such as Mn/Ca and Zn/Ca in ostracod shells of Sinocytheridea impressa and Neomonoceratina delicata from Hong Kong coastal waters. Correlations are not always significant for both species, indicating that other factors such as species-specific habitats or biomineralization processes may also play a role in the incorporation of metals. We demonstrate that the combination of multiple linear regressions using several significant sea parameters provides useful information to reconstruct shallow marine conditions including water temperature, salinity, suspended solid and total carbon in sediments. Thus, a detailed description of the marine environment in Hong Kong coastal waters can be achieved.

Micromineral Content of Swiss Chard (Beta vulgaris L. var. cicla) Leaves Grown on Zeolite-Amended Sandy Soil

Swiss chard (Beta vulgaris L. var. cicla), a popular leafy vegetable grown mainly for its ease of production and nutritional content, is normally used as a good source of microminerals iron (Fe) and zinc (Zn). Improving plant uptake of Fe and Zn could assist in reducing micromineral deficiencies in humans, which are a global problem. A greenhouse pot experiment was conducted at the Agricultural Research Council, Stellenbosch to assess the response in micromineral and soil trace elements uptake in Swiss chard grown under zeolite and sandy soil. The experiment consisted of four treatments, with six replicates arranged in a randomized complete block design. Zeolite was applied at 0%; 10%; 20% and 30% in combination with sandy soil. Swiss chard was harvested for micromineral analysis 143 days after transplanting. Soil samples were also collected at the end of each growing season. Swiss chard leaves were analysed for Fe, Zn, Mn, and Cu content with soil samples also analysed for the same elements. The study found that zeolite did not improve Swiss chard uptake of Fe, Zn and Mn. Soil Fe also had an inverse relationship to zeolite application while the residual effect of zeolite showed the same trend, but only in the second season. This study indicated that zeolite cannot be used to improve micromineral uptake by Swiss chard but can be used to rectify heavy metal-infested soils.

Incidence of foliar treatments and geographical origin on the geochemical fingerprints of leaves and fruits in olive growing.

Recently, food quality and safety has become of great interest, with a consequent demand for geographical identification of agri-food products and eco-friendly agricultural practices. In this study geochemical analyses of soils, leaves and olives from two areas in the Emilia-Romagna Region (Italy), Montiano and San Lazzaro were performed aiming at identifying geochemical fingerprints able to (1) univocally determine the locality of provenance and (2) the effect of different foliar treatments (control, dimethoate, and alternating of natural zeolitite and dimethoate in MN; Spinosad + Spyntor fly, natural zeolitite and NH4+-enriched zeolitite in SL). PCA and PLS-DA (including VIP analysis) were used to discriminate between localities and different treatments. Bioaccumulation and Translocation Coefficients (BA and TC) were studied to evaluate differences in the uptake of trace elements by plants. The PCA performed on soil data highlighted a total variance of 88.81%, allowing a good distinction between the two sites. Leaves and olives PCA showed that using trace elements it is possible to discriminate different foliar treatments (total variance: 95.64% and 91.08% in MN; 71.31% and 85.33% in SL of leaves and olives, respectively) better than the identification of their geographical origin (87.46% of leaves and 83.50% of total variance of olives). PLS-DA of all samples gave the largest contribution to the discrimination of different treatments and geographical identification. Among all elements, only Lu and Hf were able to correlate soil, leaf, and olive for geographical identification through VIP analyses, but also Rb and Sr were significant in the plant uptake (BA and TC). For the discrimination of different foliar treatments, Sm and Dy were identified in MN site, whereas Rb, Zr, La and Th correlated leaves and olives from SL. Based on trace element analyses, it can be put forward that (1) the geographical origin could be discriminated and (2) different foliar treatments applied for crop protection can be recognized, which means, reversing the reasoning that each farmer can develop a method to pinpoint his own product.

Trace Element Uptake by Willows Used for the Phytoremediation of Biosolids.

The land application of biosolids can result in the unacceptable accumulation of Trace Elements (TEs) in agricultural soil and potentially introduce xenobiotics and pathogens into the food chain. Phytoremediation of biosolids aims to minimize this risk, while producing valuable biomass. Willows, well known to accumulate zinc (Zn), are used extensively in farming systems for soil conservation, shelter and as feed supplements with demonstrable health benefits. Potentially, biosolids phytoremediation could occur on marginal lands adjacent to farmlands where willows are grown for supplementary fodder. We aimed to determine the uptake and distribution of Zn and other TEs in willows grown on soils amended with biosolids and biosolids blended with biochar, with a view to their use as stock fodder. In the Canterbury Region, New Zealand, we grew Salix 'tangaio' (S. matsudana X S. alba) in a greenhouse trial and field study. The biomass production of the willows was unaffected by biosolids and increased by the biosolids+biochar mixture. The addition of 4% biosolids (w/w) to the soil resulted in a foliar Zn concentration of 600-1000 mg kg-1, some 25 times higher than the average New Zealand pasture. Zinc concentrations were highest in the bottom leaves and increased throughout the season. Biosolids addition doubled the copper (Cu) concentration to 10 mg kg-1. Adding biochar to the system reduced the plant uptake of Cu and to a lesser extent Zn, while cadmium (Cd) uptake was unaffected. For Cd, Cu, and Zn, plant uptake was a function of the Ca(NO3)2-extractable concentration, both in greenhouse experiments and the field trial. Future work should determine the changes in plant TE uptake over several growing seasons.

Microsatellite markers-aided dissection of iron, zinc and cadmium accumulation potential in Triticum aestivum.

Wheat is a staple cereal food around the globe. It provides a significant source of proteins, carbohydrates, and other micronutrients to humans. When grown on cadmium (Cd) contaminated soils, the uptake of trace elements e.g., iron (Fe) and zinc (Zn) has also been affected drastically that in turn affected the wheat grain. In this study, wheat accessions were used to investigate the impact of soil application of Zn (5 mg/kg, 20 mg/kg) and Cd (0 mg/kg, 10 mg/kg) on accumulation of these elements in wheat grains. A total of 45 Fe, Zn, and Cd transporter-related genes were used to design 101 gene-specific SSR (simple sequence repeat) markers. In response to Cd stress, application of 20 mg/Kg Zn improved Fe (64.6 ug/g) and Zn (48.3 ug/g) accumulation in wheat grains as well as agronomic traits. Marker trait association revealed that SSR markers based on NAM-B1 gene (PR01 and PR02) were associated with Zn accumulation. Similarly, SSR markers based on TaVTL5-2B_5 (PR19 PR20), TaVTL5-2B_2 (PR25, PR26), TaVTL5-2D_3 (PR30), TaVTL2-2A (PR31), TaVTL1-6A (PR32), and TaVTL2-2D_1 (PR37) were significantly associated with Fe accumulation, while HMA3-5B1 (PR62) and TaNRAMP3-7D (PR89) were linked to Cd accumulation in grains. The highly associated markers may be used in marker-assisted selection of suitable wheat genotypes for breeding bio-fortified varieties with low Cd accumulation.

Inadvertent uptake of trace elements and its role in the physiology and evolution of hyperaccumulators

Inadvertent uptake of trace elements and its role in the physiology and evolution of hyperaccumulators