Increasing Cd Concentration Research Articles

Phytoremediation of cadmium-trichlorfon co-contaminated water by Indian mustard (Brassica juncea): growth and physiological responses

In this study, the morphological and physiological responses of Brassica juncea to the stresses of Cadmium (Cd) and trichlorfon (TCF), and the phytoremediation potential of B. juncea to Cd and TCF were investigated under hydroponics. Results showed that Cd exhibited strong inhibition on biomass and root morphology of B. juncea as Cd concentration increased. The chlorophyll a fluorescence intensity and chlorophyll content of B. juncea decreased with the increased Cd concentration, whereas the malondialdehyde and soluble protein contents and superoxide dismutase activity increased. TCF with different concentrations showed no significant influence on these morphological and physiological features of B. juncea. The biomass and physiological status of B. juncea were predominantly regulated by Cd level under the co-exposure of Cd and TCF. B. juncea could accumulate Cd in different plant parts, as well as showed efficient TCF degradation performance. A mutual inhibitory removal of Cd and TCF was observed under their co-system. The present study clearly signified the physiological responses and phytoremediation potential of B. juncea toward Cd and TCF, and these results suggest that B. juncea can be used as an effective phytoremediation agent for the Cd-TCF co-contamination in water.

NaCl-mediated strategies for the trade-off between Cd bioconcentration and translocation in Solanum nigrum L

Salt interference significantly affects the behavior of heavy metals in the environment. This study compared and analyzed the response process, migration, and transformation of cadmium (Cd) in the hyperaccumulator Solanum nigrum (S. nigrum) under different NaCl levels to reveal the interference mechanisms of salt in plant remediation of Cd-contaminated soil. The results showed that Cd and salt stress significantly inhibited the growth of plants. The stress effect had more potent growth inhibition at the root than aboveground, thus inducing changes in the spatial configuration of the plants (decreased root-to-aboveground biomass ratio). Salt could activate Cd in plants, enhancing the inhibitory effect on plant growth. Salt increased Cd bioavailability due to the rhizosphere acidification effect, increasing plants’ Cd accumulation. The Cd bioconcentration factor in plant roots peaked during the high Cd-high salt treatment (117.10), but the Cd accumulation of plants peaked during the high Cd-low salt treatment (233.04 μg plant−1). Salt additions and increased Cd concentrations enhanced root compartmentalization, inhibiting Cd transport to the aboveground. Changes in Fourier-transform infrared spectroscopy (FTIR) measurements confirmed that the functional groups in plants provided binding sites for Cd. These findings can help guide the phytoremediation of Cd contamination under saline soil conditions.

Metallochaperone protein OsHIPP17 regulates the absorption and translocation of cadmium in rice (Oryza sativa L.)

Heavy metal-associated isoprenylated plant proteins (HIPPs) play vital roles in regulating heavy metal responding activities in plants. Yet only a handful of studies have characterized the functions of HIPPs. In this study, a novel HIPP member OsHIPP17 was functionally characterized, which was involved in the tolerance of yeast and plants to cadmium (Cd). The Cd accumulation in yeast cells was increased due to the overexpression of OsHIPP17. Nevertheless, the overexpression of OsHIPP17 in Arabidopsis thaliana resulted in compromised growth under Cd stress. Meanwhile, the mutation of OsHIPP17 resulted in 38.9–40.9 % increase of Cd concentration in rice roots as well as 14.3–20.0 % decrease of Cd translocation factor. Further investigation of the genes responsible for Cd absorption and transporter indicated that the expression levels of these genes were also perturbed. In addition, two OsHIPP17-interacting proteins, OsHIPP24 and OsLOL3 were identified in a yeast two hybrid assay. Further analysis of their functions revealed that OsHIPP24 or OsLOL3 may be involved in the regulation of Cd tolerance by OsHIPP17 in rice. All above results implied that OsHIPP17 may affect Cd resistance by regulating the absorption and translocation of Cd in rice.

A small extent of seawater intrusion significantly enhanced Cd uptake by rice in coastal paddy fields

Paddy fields located around estuaries suffer from seawater intrusion, and how and to what extent salinity levels influence Cd accumulation in rice grains is still unclear. Pot experiments were carried out by cultivating rice under alternating flooding and drainage conditions with different salinity levels (0.2‰, 0.6‰ and 1.8‰). The Cd availability was greatly enhanced at 1.8‰ salinity due to the competition for binding sites by cations and the formation of Cd complexation with anions, which also contributed to Cd uptake by rice roots. The soil Cd fractions were investigated and found that the Cd availability significantly decreased during flooding stage, while it rapidly increased after soil drainage. During drainage stage, Cd availability was greatly enhanced at 1.8‰ salinity mainly attributed to the formation of CdCln2−n. The kinetic model was established to quantitatively evaluate Cd transformation, and it found that the release of Cd from organic matter and Fe-Mn oxides was greatly enhanced at 1.8‰ salinity. The results of pot experiments showed that there was a significant increase in Cd content in rice roots and grains in the treatment of 1.8‰ salinity, because the increasing salinity induced an increase in Cd availability and upregulation of key genes regulating Cd uptake in rice roots. Our findings elucidated the key mechanisms by which high salinity enhanced Cd accumulation in rice grains, and more attention should be given to the food safety of rice cultivated around estuaries.

Effects of foliar applications of ascobin on seed protein accumulation in soybean (Glycine max (L.) Merrill) JS 1215 grown under cadmium stress

Different natural and anthropogenic activities have contributed to the prevalence of various environmental abiotic stressors that negatively affect agricultural yields worldwide. Also, more adverse impacts can be seen in legumes due to their susceptibility to abiotic stresses compared to cereals. The present study sought to understand cadmium's impact and its alleviation using ascobin on several seed protein properties of soybean (Glycine max). The total seed protein content, estimated using the semi-micro Kjeldahl method, was 36.25% without ascobin (control) at the highest cadmium (Cd) concentration, i.e., 30 mg per kg of soil. The protein content was restored to the highest level (43.75%) with 500 mg/L of ascobin at 10 mg Cd/kg of soil compared to the control without Cd. There was a noticeable decrease in total seed protein content in all sets under control conditions (i.e., without ascobin spray). Also, a negative correlation was found between increasing Cd concentration and the amount of free amino acids, quantified using Lee and Takahashi’s protocol in the seed proteins. The electrophoretic analysis using Gelanalyzer on SDS gels, as per Laemmli’s formulation, revealed that the 7S-Conglycinin protein subfraction was more affected than the 11S-Glycinin subfraction. The analysis revealed how Cd toxicity in soybean plants led to decreased seed protein content and altered proportion of two globulin sub-fractions (glycinin and β-conglycinin). Additionally, it affected the free amino acid content, potentially determining the seeds' nutritional value. However, foliar application of ascobin helped the plants to mitigate these Cd-induced changes and restore the seed quality.

Increased soil cadmium concentrations enhanced poplar defence against a leaf pathogenic fungus infection

AbstractSince heavy metals are toxic to herbivores and pathogens, the Elemental defence hypothesis suggested that metals accumulated in plants might serve as defence against herbivores and pathogen attacks. However, several studies have tested this hypothesis with regard to pathogen resistance are limited. Most existing studies used herbaceous species as study model while studies on tree species are still lacking. In this study, we used poplar as a study model, to investigate whether soil treatment with five different cadmium (Cd) concentrations can protect plants from artificial infection of a leaf pathogenic fungus. The results showed that the Cd concentrations accumulated in plant leaves were positively correlated with increasing Cd concentrations amended in the soil while negatively correlated with the disease severity index (DSI) of plants after pathogen infection. Additional partial correlation analysis indicated that the plant DSI was only significantly correlated with Cd concentration accumulated in plant leaves while plant growth parameters and other leaf substances showed no clear correlations. The in vitro toxicity test of fungal mycelium grown on a series of Cd concentrations amended in the artificial medium further showed that the mycelium growth decreased with increasing Cd concentrations contained in the medium, which confirmed the biological toxicity of Cd on this fungus independently of other organic defensive substances present in poplar leaves. In conclusion, our study supported the Elemental defence hypothesis and proved that even a lower accumulation of Cd in poplar plants can provide sufficient protection against leaf pathogen infection.

Evidence Linking Cadmium Exposure and β2-Microglobulin to Increased Risk of Hypertension in Diabetes Type 2.

The most common causes of chronic kidney disease, diabetes, and hypertension are significant public health issues worldwide. Exposure to the heavy metal pollutant, cadmium (Cd), which is particularly damaging to the kidney, has been associated with both risk factors. Increased levels of urinary β2-microglobulin (β2M) have been used to signify Cd-induced kidney damage and circulating levels have been linked to blood pressure control. In this study we investigated the pressor effects of Cd and β2M in 88 diabetics and 88 non-diabetic controls, matched by age, gender and locality. The overall mean serum β2M was 5.98 mg/L, while mean blood Cd and Cd excretion normalized to creatinine clearance (Ccr) as ECd/Ccr were 0.59 µg/L and 0.0084 µg/L of filtrate (0.95 µg/g creatinine), respectively. The prevalence odds ratio for hypertension rose by 79% per every ten-fold increase in blood Cd concentration. In all subjects, systolic blood pressure (SBP) showed positive associations with age (β = 0.247), serum β2M (β = 0.230), and ECd/Ccr (β = 0.167). In subgroup analysis, SBP showed a strong positive association with ECd/Ccr (β = 0.303) only in the diabetic group. The covariate-adjusted mean SBP in the diabetics of the highest ECd/Ccr tertile was 13.8 mmHg higher, compared to the lowest tertile (p = 0.027). An increase in SBP associated with Cd exposure was insignificant in non-diabetics. Thus, for the first time, we have demonstrated an independent effect of Cd and β2M on blood pressure, thereby implicating both Cd exposure and β2M in the development of hypertension, especially in diabetics.

Effects of lithology and acid mine drainage on Cd concentration and isotope distribution in a large riverine system, Guangxi Province, South China

Cadmium is highly toxic to plants, animals, and humans. When assessing its risk, it is critical to distinguish anthropogenic activities from natural weathering processes. Specific Cd isotopes have been used to track the source and fate of Cd in the environment. However, Cd isotopic signatures in soils and sediments and its fractionation in large river systems, especially in high-population areas and within complex Cd source regions, remain poorly understood. Using chemical and isotope analyses, this study identifies Cd sources in the Xijiang riverine system, China, as being the result of natural weathering and acid mine drainage. Cadmium isotopic fractionation between stream sediment and topsoil was uniform, with Δ114/110Cdstream sediment–topsoil values averaging 0.50‰ ± 0.04‰ through natural weathering processes and fractionation being controlled mainly by the Cd isotopic composition of acid mine drainage. During the natural weathering of carbonate sediments, Ca2+ and HCO3− in soils tend to drain into the Xun River with leachate, resulting in a weakly alkaline water column with increasing Cd contents in stream sediments. In mining regions, H+, Cd2+, Zn2+, and other metal ions are prone to release from sphalerite into solution under supergene conditions, ultimately resulting in high Cd contents in sediments of the Meng River. This study highlights the use of Δ114/110Cdstream sediment–topsoil values as a tool for distinguishing the effects of anthropogenic activities from those of natural weathering processes in river systems at risk of Cd pollution.

The Expression of the StNRAMP2 Gene Determined the Accumulation of Cadmium in Different Tissues of Potato.

Cadmium (Cd) is a toxic metal that threatens human health when enriched in crops. NRAMPs are a family of natural macrophage proteins reported to play a key role in Cd transport in plants. In order to explore the gene regulation mechanism of potato under Cd stress and the role of NRAMPs family in it, this study analyzed the gene expression differences of two different Cd accumulation levels in potato after 7 days of 50 mg/kg Cd stress and screened out the key genes that may play a major role in the differential accumulation of Cd in different varieties. Additionally, StNRAMP2 was selected for verification. Further verification showed that the StNRAMP2 gene plays an important role in the accumulation of Cd in potato. Interestingly, silencing StNRAMP2 increased Cd accumulation in tubers but significantly decreased Cd accumulation in other sites, suggesting a critical role of StNRAMP2 in Cd uptake and transport in potatoes. To further confirm this conclusion, we performed heterologous expression experiments in which overexpression of StNRAMP2 gene in tomato resulted in a threefold increase in Cd content, which further confirmed the important role of StNRAMP2 in the process of Cd accumulation compared with wild-type plants. In addition, we found that the addition of Cd to the soil increased the activity of the plant antioxidant enzyme system, and silencing StNRAMP2 partially reversed this effect. This suggests that the StNRAMP2 gene plays an important role in plant stress tolerance, and future studies could further explore the role of this gene in other environmental stresses. In conclusion, the results of this study improve the understanding of the mechanism of Cd accumulation in potato and provide experimental basis for remediation of Cd pollution.

Cadmium Reduction in Spring Wheat: Root Exudate Composition Affects Cd Partitioning Between Roots and Shoots

Cadmium (Cd) in cereals is one of the major sources of Cd intake by human diets, and solutions to reduce Cd concentrations in wheat still need to be developed. Plant breeding, by selecting low-Cd varieties, can be an important tool to reduce Cd in crops. Knowing the genotypic variation in Cd accumulation and furthering our understanding of the impact of root exudates composition on Cd accumulation in crops may provide valuable information for plant breeding. In this study, we selected nine spring wheat varieties and analysed the accumulation and distribution of Cd in shoots, roots, root surfaces and kernels in relation to their qualitative and quantitative composition of root exudates, determined by 1H-NMR (Proton Nuclear Magnetic Resonance). Results showed that the Cd concentration in shoots at an early stage could be used as a predictor for Cd concentration in kernels. Total Cd uptake was not correlated to the mobility of Cd in the rhizosphere, but total Cd was negatively correlated to Cd adsorbed at the root surface. Furthermore, (i) exudation of organic acids (primarily succinate and acetate) increased Cd concentration in shoots, and (ii) exudation of nucleosides, DNA (deoxyribonucleic acid) degradation products, increased Cd adsorption at the root surface. Therefore, root exudates composition should be taken into account when selecting for low-Cd wheat traits.

New Insight into the Function of Dopamine (DA) during Cd Stress in Duckweed (Lemna turionifera 5511).

Dopamine (DA), a kind of neurotransmitter in animals, has been proven to cause a positive influence on plants during abiotic stress. In the present study, the function of DA on plants under cadmium (Cd) stress was revealed. The yellowing of duckweed leaves under Cd stress could be alleviated by an exogenous DA (10/20/50/100/200 μM) supplement, and 50 μM was the optimal concentration to resist Cd stress by reducing root breakage, restoring photosynthesis and chlorophyll content. In addition, 24 h DA treatment increased Cd content by 1.3 times in duckweed under Cd stress through promoting the influx of Cd2+. Furthermore, the gene expression changes study showed that photosynthesis-related genes were up-regulated by DA addition under Cd stress. Additionally, the mechanisms of DA-induced Cd detoxification and accumulation were also investigated; some critical genes, such as vacuolar iron transporter 1 (VIT1), multidrug resistance-associated protein (MRP) and Rubisco, were significantly up-regulated with DA addition under Cd stress. An increase in intracellular Ca2+ content and a decrease in Ca2+ efflux induced by DA under Cd stress were observed, as well as synchrony with changes in the expression of cyclic nucleotide-gated ion channel 2 (CNGC2), predicting that, in plants, CNGC2 may be an upstream target for DA action and trigger the change of intracellular Ca2+ signal. Our results demonstrate that DA supplementation can improve Cd resistance by enhancing duckweed photosynthesis, changing intracellular Ca2+ signaling, and enhancing Cd detoxification and accumulation. Interestingly, we found that exposure to Cd reduced endogenous DA content, which is the result of a blocked shikimate acid pathway and decreased expression of the tyrosine aminotransferase (TAT) gene. The function of DA in Cd stress offers a new insight into the application and study of DA to Cd phytoremediation in aquatic systems.

Effects of Nitrogen and Zinc Fertilization on Alleviating Cadmium Accumulation in Durum Wheat Grains

ABSTRACT Cadmium (Cd) accumulation in durum wheat (Triticum durum L.) is of particular concern compared to the other commonly cultivated cereals. This study was conducted to determine the effects of zinc (Zn) and nitrogen (N) applications on grain Cd concentration of durum wheat grown in a Cd contaminated soil. The experimental design consisted of randomized plots with four replications. The treatments included low and adequate (0.05 and 5 mg kg−1) Zn doses, and inadequate, optimal and high (200, 400 and 600 mg kg−1) N doses. Cadmium application rates were 0 and 5 mg kg−1. The findings demonstrated that Cd application caused a significant increase in grain Cd concentrations, and a decrease in straw and grain yields under low and adequate doses of Zn and all N doses. However, increasing N applications with adequate soil Zn caused an increase in the straw and grain yields and a significant decrease in grain Cd concentration. The grain Cd concentration in low Zn and optimum N treatment under Cd application was 6206 µg kg−1, while the grain Cd concentration decreased by 26.3% (4574 µg kg−1) in the Zn and optimum N treatment. In addition, the grain Zn concentration of durum wheat under low soil Zn conditions was decreased in Cd application, whereas the grain Zn concentration increased in Cd application under adequate soil Zn concentration. The results revealed that combined application of N and Zn in Zn deficient soils is highly effective at decreasing Cd accumulation in wheat grains compared to individual applications.

The influence of food on in vivo Cd and Pb relative bioavailability in rice

Related information on the influence of synchronously digested food components on Cd and Pb bioavailability in rice has been limited. Here, the relative bioavailabilities of Cd and Pb from two rices were determined under fed states in conjunction with 5 foods (namely, pork, egg, milk, apple, and cabbage) using an in vivo mouse model. The Cd and Pb relative bioavailabilities were 54.9 to 92.1% and 21.4 to 75.4%, respectively. The addition of pork and egg increased Cd concentrations and relative bioavailability due to the high content of fats and proteins. Adding milk powder and cabbage significantly decreased Pb concentration in the mouse kidney and liver. In vivo Pb relative bioavailability was negatively correlated with Ca and fiber content in food matrices and Ca or Fe content in the mouse kidney or liver. Moreover, oral bioavailability-corrected risk assessment was used to evaluate the realistic risk from rice consumption with other food matrices. The present work highlights the importance of finding valid dietary strategies to reduce the risk of heavy-metal exposure caused by rice consumption.

Microbial cell wall sorption and Fe-Mn binding in rhizosphere contribute to the obstruction of cadmium from soil to rice.

Screening high-tolerant microorganisms to cadmium (Cd) and revealing their bio-obstruction mechanism could be significant for Cd regulation from farmland to the food chain. We examined the tolerance and bio-removal efficiency of Cd ions of two bacterial strains, Pseudomonas putida 23483 and Bacillus sp. GY16, and measured the accumulation of Cd ions in rice tissues and its different chemical forms in soil. The results showed that the two strains had high tolerance to Cd, but the removal efficiency was decreased successively with increasing Cd concentrations (0.05 to 5 mg kg-1). Cell-sorption accounted for the major proportion of Cd removal compared with excreta binding in both strains, which was conformed to the pseudo-second-order kinetics. At the subcellular level, Cd was mostly taken up by the cell mantle and cell wall, and only a small amount entered into the cytomembrane and cytoplasmic with time progressed (0 to 24 h) in each concentration. The cell mantle and cell wall sorption decreased with increasing Cd concentration, especially in the cytomembrane and cytoplasmic. The scanning electron microscope (SEM) and energy dispersive X-ray (EDS) analysis verified that Cd ions were attached to the cell surface, and the functional groups of C-H, C-N, C=O, N-H, and O-H in the cell surface may participate in cell-sorption process tested by the FTIR analysis. Furthermore, inoculation of the two strains significantly decreased Cd accumulation in rice straw and grain but increased in the root, increased Cd enrichment ratio in root from soil, decreased Cd translocation ratio from root to straw and grain, and increased the Cd concentrations of Fe-Mn binding form and residual form in rhizosphere soil. This study highlights that the two strains mainly removed Cd ions in solution through biosorption and passivated soil Cd as Fe-Mn combined form ascribe to its characteristics of manganese-oxidizing, eventually achieving bio-obstruction of Cd from soil to rice grain.

Regulation of gut bacteria in silkworm (Bombyx mori) after exposure to endogenous cadmium-polluted mulberry leaves

Soil cadmium (Cd) pollution presents a severe pollution burden to flora and fauna due to its non-degradability and transferability. The Cd in the soil is stressing the silkworm (Bombyx mori) out through a soil-mulberry-silkworm system. The gut microbiota of B.mori are reported to shape host health. However, earlier research had not reported the effect of endogenous Cd-polluted mulberry leaves on the gut microbiota of B.mori. In the current research, we compared the phyllosphere bacteria of endogenous Cd-polluted mulberry leaves at different concentrations. The investigation of the gut bacteria of B.mori fed with the mulberry leaves was done to evaluate the impact of endogenous Cd- polluted mulberry leaves on the gut bacteria of the silkworm. The results revealed a dramatic change in the gut bacteria of B.mori whereas, the changes in the phyllosphere bacteria of mulberry leaves in response to an increased Cd concentration were insignificant. It also increased the α-diversity and altered the gut bacterial community structure of B. mori. A significant change in the abundance of dominant phyla of gut bacteria of B.mori was recorded. At the genus level, the abundance of Enterococcus, Brachybacterium and Brevibacterium group related to disease resistance, and the abundance of Sphingomonas, Glutamicibacter and Thermus related to metal detoxification was significantly increased after Cd exposure. Meanwhile, there was a significant decrease in the abundance of the pathogenic bacteria Serratia and Enterobacter. The results demonstrated that endogenous Cd-polluted mulberry leaves caused perturbations in the gut bacterial composition of B.mori, which may driven by Cd content rather than phyllosphere bacteria. A significant variation in the specific bacterial community indicated the adaptation of B. mori gut for its role in heavy metal detoxification and immune function regulation. The results of this study help to understand the bacterial community associated with endogenous Cd-polluted resistance in the gut of B.mori, which proves to be a novel addition in describing its response in activating the detoxification mechanism and promoting its growth and development. This research work will help to explore the other mechanisms and microbiota associated with the adaptations to mitigate the Cd pollution problems.

Glass Wastes Sorption Efficiency for Removing Cadmium from Aqueous Solutions

This research aims to test the ability of glass waste powder to adsorb cadmium from aqueous solutions. The glass wastes were collected from the Glass Manufacturing Factory in Ramadi. The effect of concentration and reaction time on sorption was tested through a series of laboratory experiments. Four Cd concentrations (20, 40, 60, and 80) as each concentration was tested ten times for 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 min. Solid (glass wastes) to liquid was 2g to 30ml was fixed in each experiment where the total volume of the solution was 30ml. The pH, total dissolved salts and electrical conductivity were measured at 30ºC. The equilibrium concentration was determined at 25 minutes, thereafter it was noted that the sorption (%) decreased whenever increasing Cd concentration. Langmuir and Freundlich's equations showed that the sorption intensity is 2.402 and the adsorption capacity is 3.126, and the sorption of Cd fits with the Freundlich equation. Consequently, it was clarified how glass waste material can be utilized for reducing the high levels of Cd concentrations from aqueous solutions as a step to combat environmental pollution.

Multiferroics Made via Chemical Co-Precipitation That Is Synthesized and Characterized as Bi(1−x)CdxFeO3

Cd-doped BiFeO3 powders, with varying doping concentrations of Cd (Bi(1−x)CdxFeO3, where x = 0–0.3), were prepared through a facile chemical co-precipitation method and calcinated at 550 °C in the air. The BiFeO3 has a rhombohedral crystal structure, which changes to an orthorhombic crystal structure with an increase in Cd doping. The presence of dopant has also altered the bandgap of material suppressing it from 2.95 eV to 2.51 eV, improving the visible light absorption. Vibrating sample magnetometry (VSM) confirmed stronger ferromagnetic character for Bi0.7Cd0.3FeO3 with a coercivity of 250 Oe, and remnant magnetization was 0.15 emu/g, which is because of the misalignment of the two sublattices of perovskite structure after doping resulting in the imbalanced magnetic moment giving rise to net nonzero magnetic behavior. The particle size reduction is observed with an increase in the doping concentration of Cd.

Comparative proteome profiles of Polygonatum cyrtonema Hua rhizomes (Rhizoma Ploygonati) in response to different levels of cadmium stress

BackgroundThe Polygonatum cyrtonema Hua rhizomes (also known as Rhizoma Polygonati, RP) are consumed for their health benefits. The main source of the RP is wild P. cyrtonema populations in the Hunan province of China. However, the soil Cadmium (Cd) content in Huanan is increasing, thus increasing the risks of Cd accumulation in RP which may end up in the human food chain. To understand the mechanism of Cd accumulation and resistance in P. cyrtonema, we subjected P. cyrtonema plants to four levels of Cd stress [(D2) 1, (D3) 2, (D4) 4, and (D5) 8 mg/kg)] compared to (D1) 0.5 mg/kg.ResultsThe increase in soil Cd content up to 4 mg/kg resulted in a significant increase in tissue (root hair, rhizome, stem, and leaf) Cd content. The increase in Cd concentration variably affected the antioxidant enzyme activities. We could identify 14,171 and 12,115 protein groups and peptides, respectively. There were 193, 227, 260, and 163 differentially expressed proteins (DEPs) in D2, D3, D4, and D5, respectively, compared to D1. The number of downregulated DEPs increased with an increase in Cd content up to 4 mg/kg. These downregulated proteins belonged to sugar biosynthesis, amino acid biosynthesis-related pathways, and secondary metabolism-related pathways. Our results indicate that Cd stress increases ROS generation, against which, different ROS scavenging proteins are upregulated in P. cyrtonema. Moreover, Cd stress affected the expression of lipid transport and assembly, glycolysis/gluconeogenesis, sugar biosynthesis, and ATP generation.ConclusionThese results suggest that an increase in soil Cd content may end up in Huangjing. Cadmium stress initiates expression changes in multiple pathways related to energy metabolism, sugar biosynthesis, and secondary metabolite biosynthesis. The proteins involved in these pathways are potential candidates for manipulation and development of Cd stress-tolerant genotypes.

Sex differences in cadmium and lead concentrations in different biological matrices in athletes. Relationship with iron status

PurposeThe present study aimed to analyse sex differences in cadmium and lead concentrations in plasma, urine, platelets and erythrocytes and to relate these concentrations to biomarkers of iron status. MethodsA total of 138 soccer players divided according to sex: men (n = 68) and women (n = 70) participated in the present study. All participants resided in the city of Cáceres (Spain). Erythrocyte, haemoglobin, platelet, plateletcrit, ferritin and serum iron values were determined. Cadmium and lead concentrations were quantified by inductively coupled plasma mass spectrometry. ResultsThe women had lower haemoglobin, erythrocyte, ferritin and serum iron values (p < 0.01). Regarding cadmium, the women showed higher concentrations in plasma, erythrocytes and platelets (p < 0.05). As for lead, they also showed higher concentrations in plasma, relative values of erythrocytes and relative values of platelets (p < 0.05). Significant correlations were observed between cadmium and lead concentrations with biomarkers of iron status. ConclusionsCadmium and lead concentrations are different between sexes. Biological differences between sexes and iron status could influence cadmium and lead concentrations. Lower serum iron concentrations and markers of Fe status increase Cd and Pb concentrations. Ferritin and serum iron have been directly related to increased Cd and Pb excretion.

The original polyethylene microplastics inhibit the growth of sweet potatoes and increase the safety risk of cadmium.

Microplastics (MPs) and heavy metals (HMs) co-exist in sweet potato fields of China. As the main component of agricultural field mulch and one of the most polluting and harmful HMs, the effects of polyethylene microplastics (PE MPs) and cadmium (Cd) on sweet potato and soil environment are remains unclear. Here, pot and hydroponic experiments are used to explore the effects of original and weathered PE MPs on growth and Cd uptake of sweet potatoes. The results of pot experiments reveal that compared with the control (0%), 5% of weathered PE MPs can significantly increase soil electrical conductivity (EC); both 5% of the original PE MPs and weathered PE MPs can significantly reduce the concentration of Olsen phosphorus (P) and Olsen potassium (K) in soil, inhibit plant growth, but significantly increase Cd accumulation and glutathione (GSH) level in tissues of sweet potatoes, and also induce membrane lipid peroxidation. In addition, compared to 5% weathered PE MPs, 5% original PE MPs significantly reduce soil EC, growth and peroxidase level of sweet potatoes, but significantly increase Cd concentration in leaves and stems. The results of hydroponic experiment show that original PE MPs significantly increase the P, K, and Cd adsorption compared with weathered PE MPs, and Cd increases the original PE MPs accumulation in the root cortex but decrease PE MPs accumulation in shoots. To sum up, our study investigates the differences and reasons of the effects of original and weathered PE MPs on growth and Cd absorption of sweet potatoes.