Phytoremediation Of Soils Research Articles

Changes in Lolium perenne L. rhizosphere microbiome during phytoremediation of Cd- and Hg-contaminated soils

The contamination of soil and water by metals such as mercury (Hg) and cadmium (Cd) has been increasing in recent years, because of anthropogenic activities such as mining and agriculture, respectively. In this work, the changes in the rhizosphere microbiome of Lolium perenne L. during the phytoremediation of soils contaminated with Hg and Cd were evaluated. For this, two soil types were sampled, one inoculated with mycorrhizae and one without. The soils were contaminated with Hg and Cd, and L. perenne seeds were sown and harvested after 30 days. To assess changes in the microbiome, DNA isolation tests were performed, for which samples were subjected to two-step PCR amplification with specific 16S rDNA V3-V4 primers (337F and 805R). With mycorrhizae, changes had been found in the absorption processes of metals and a new distribution. While with respect to microorganisms, families such as the Enterobacteriaceae have been shown to have biosorption and efflux effects on metals such as Hg and Cd. Mycorrhizae then improve the efficiency of removal and allow the plant to better distribute the absorbed concentrations. Overall, L. perenne is a species with a high potential for phytoremediation of Cd- and Hg-contaminated soils in the tropics. Inoculation with mycorrhizae modifies the phytoremediation mechanisms of the plant and the composition of microorganisms in the rhizosphere. Mycorrhizal inoculation and changes in the microbiome were associated with increased plant tolerance to Cd and Hg. Microorganism-assisted phytoremediation is an appropriate alternative for L. perenne.

Phytoremediation Competence of Composite Heavy-Metal-Contaminated Sediments by Intercropping Myriophyllum spicatum L. with Two Species of Plants.

A variety of remediation approaches have been applied to reduce the harm and diffusion of heavy metals in aquatic sediments; however, phytoremediation in co-contaminated soils is still not clear. In order to explore the phytoremediation of sediments contaminated by Cu and Pb, two submerged plants with different characteristics, Vallisneria natans and Hydrilla verticillata, were interplanted with Myriophyllum spicatum. By simulating a submerged plant ecological environment, medium-scale-simulated ecological remediation experiments were carried out. The results showed that the two planting patterns were effective in repairing the sediments in the Cu and Pb contaminated sediments. The intercropping of Myriophyllum spicatum and Vallisneria natans can be used as the plant stabilizer of Cu because of the TF > 1 and BCF < 1, and the intercropping with Hydrilla verticillata can regulate the enrichment efficiency of Myriophyllum spicatum. The removal rates of Cu and Pb in sediments reached 26.1% and 68.4%, respectively, under the two planting patterns. The risk grade of the restored sediments was RI < 150, indicating a low risk.

A novel gene SpCTP3 from the hyperaccumulator Sedum plumbizincicola redistributes cadmium and increases its accumulation in transgenic Populus × canescens.

A cadmium (Cd) tolerance protein (SpCTP3) involved in the Sedum plumbizincicola response to Cd stress was identified. However, the mechanism underlying the Cd detoxification and accumulation mediated by SpCTP3 in plants remains unclear. We compared wild-type (WT) and SpCTP3-overexpressing transgenic poplars in terms of Cd accumulation, physiological indices, and the expression profiles of transporter genes following with 100 μmol/L CdCl2. Compared with the WT, significantly more Cd accumulated in the above-ground and below-ground parts of the SpCTP3-overexpressing lines after 100 μmol/L CdCl2 treatment. The Cd flow rate was significantly higher in the transgenic roots than in the WT roots. The overexpression of SpCTP3 resulted in the subcellular redistribution of Cd, with decreased and increased Cd proportions in the cell wall and the soluble fraction, respectively, in the roots and leaves. Additionally, the accumulation of Cd increased the reactive oxygen species (ROS) content. The activities of three antioxidant enzymes (peroxidase, catalase, and superoxide dismutase) increased significantly in response to Cd stress. The observed increase in the titratable acid content in the cytoplasm might lead to the enhanced chelation of Cd. The genes encoding several transporters related to Cd2+ transport and detoxification were expressed at higher levels in the transgenic poplars than in the WT plants. Our results suggest that overexpressing SpCTP3 in transgenic poplar plants promotes Cd accumulation, modulates Cd distribution and ROS homeostasis, and decreases Cd toxicity via organic acids. In conclusion, genetically modifying plants to overexpress SpCTP3 may be a viable strategy for improving the phytoremediation of Cd-polluted soil.

Assistant effects of spent mushroom substrate and its derived biochar on soil phytoremediation

Assistant effects of spent mushroom substrate and its derived biochar on soil phytoremediation

Vanadium-resistant endophytes modulate multiple strategies to facilitate vanadium detoxification and phytoremediation in Pteris vittata.

Vanadium (V) contamination of soils poses potential risks to humans and ecosystems. This study was conducted to evaluate the effects of endophyte-assisted phytoremediation and to determine the mechanisms involved in V detoxification and plant growth promotion. Results showed that the endophytic bacterium Serratia marcescens PRE01 could successfully colonize the roots and increase the total V uptake of Pteris vittata by 25.4 %, with higher plant biomass and V accumulation in roots. Endophyte inoculation significantly improved the secretion of phytic, malic, and oxalic acids and accelerated FeVO4 dissolution and subsequent Fe and V uptake in the rhizosphere. Under V stress without inoculation, V removed by shoot uptake, root uptake, and root surface adsorption accounted for 21.76 %, 42.14 %, and 30.93 % of the total V removal efficiency, respectively. To detoxify excess V, PRE01 effectively strengthened the adsorption of V on the root surface, with an increase in its contribution to the total V removal efficiency from 30.93 % to 38.10 %. Furthermore, beneficial endophytes could alleviate oxidative damage caused by V stress by reinforcing the plant antioxidant system and promoting V(V) reduction in root tissues. These findings clearly reveal that inoculation with endophytes is a promising method for modulating multiple strategies to enhance the phytoremediation of V-contaminated soils.

Genome-wide identification of the class III peroxidase gene family of sugarcane and its expression profiles under stresses.

Plant-specific Class III peroxidases (PRXs) play a crucial role in lignification, cell elongation, seed germination, and biotic and abiotic stresses. The class III peroxidase gene family in sugarcane were identified by bioinformatics methods and realtime fluorescence quantitative PCR. Eighty-two PRX proteins were characterized with a conserved PRX domain as members of the class III PRX gene family in R570 STP. The ShPRX family genes were divided into six groups by the phylogenetic analysis of sugarcane, Saccharum spontaneum, sorghum, rice, and Arabidopsis thaliana. The analysis of promoter cis-acting elements revealed that most ShPRX family genes contained cis-acting regulatory elements involved in ABA, MeJA, light responsiveness, anaerobic induction, and drought inducibility. An evolutionary analysis indicated that ShPRXs was formed after Poaceae and Bromeliaceae diverged, and tandem duplication events played a critical role in the expansion of ShPRX genes of sugarcane. Purifying selection maintained the function of ShPRX proteins. SsPRX genes were differentially expressed in stems and leaves at different growth stages in S. spontaneum. However, ShPRX genes were differentially expressed in the SCMV-inoculated sugarcane plants. A qRT-PCR analysis showed that SCMV, Cd, and salt could specifically induce the expression of PRX genes of sugarcane. These results help elucidate the structure, evolution, and functions of the class III PRX gene family in sugarcane and provide ideas for the phytoremediation of Cd-contaminated soil and breeding new sugarcane varieties resistant to sugarcane mosaic disease, salt, and Cd stresses.

Proteomic analysis reveals differential responsive mechanisms in Solanum nigrum exposed to low and high dose of cadmium

Cadmium (Cd) contamination is becoming a widespread environmental problem. However, the differential responsive mechanisms of Cd hyperaccumulator Solanum nigrum to low or high dose of Cd are not well documented. In this study, phenotypic and physiological analysis firstly suggested that the seedlings of S. nigrum showed slight leaf chlorosis symptoms under 25 μM Cd and severe inhibition on growth and photosynthesis under 100 μM Cd. Further proteomic analysis identified 105 differentially expressed proteins (DEPs) in the Cd-treated leaves. Under low dose of Cd stress, 47 DEPs are mainly involved in primary metabolic processes, while under high dose of Cd stress, 92 DEPs are mainly involved in photosynthesis, energy metabolism, production of phytochelatin and reactive oxygen species (ROS). Protein-protein interaction (PPI) network analysis of DEPs support above differential responses in the leaves of S. nigrum to low and high dose of Cd treatments. This work provides the differential responsive mechanisms in S. nigrum to low and high dose of Cd, and the theoretical foundation for the application of hyperaccumulating plants in the phytoremediation of Cd-contaminated soils.

An extension of the characteristic curve model of plant species behavior in heavy metal soils.

This article proposes a mathematical model to characterize phytoremediation processes in soils contaminated with heavy metals. In particular, the proposed model constructs characteristic curves for the concentrations of several metals (As, Cd, Cu, Fe, Pb, Sb, and Zn) in soils and plants based on the experimental data retrieved from several bibliographical sources comprising 305 vegetal species. The proposed model is an extension of previous models of characteristic curves in phytoremediation processes developed by Lam et al. for root measurements using the bioconcentration factor. However, the proposed model extends this approach to consider roots, as well as aerial parts and shoots of the plant, while at the same time providing a less complex mathematical formula compared to the original. The final model shows an adjusted R2 of 0.712, and all its parameters are considered statistically significant. The model may be used to assess samples from a given plant species to identify its potential as an accumulator in the context of soil phytoremediation processes. Furthermore, a simplified version of the model was constructed using an approximation to provide an easy-to-compute alternative that is valid for concentrations below 37,000mg/kg. This simplified model shows results similar to the original model for concentrations below this threshold and it uses an adjusted factor defined as [Formula: see text] that must be compared with a threshold depending on the metal, type of measurement, and target (e.g., accumulator or hyperaccumulator). The full model construction shows that 90 out of the 305 species assessed have a potential behavior as accumulators and 10 of them as hyperaccumulators. Finally, out of the 1405 experimental measurements, 1177 were shown to be accumulators or hyperaccumulators. In particular, 85% of the results coincide with the reported values, thus validating the proposed model.

SELECTION OF HIGHLY PRODUCTIVE GENOTYPES OF SUGAR SORGHUM (SORGHUM BICOLOR L) FOR FURTHER USE IN PHYTOREMEDIATION OF SOILS FROM HEAVY METALS

at the moment, soil pollution is the main environmental problem, which leads to a great need for the restoration of contaminated soils using the most appropriate and effective cleaning methods. Conventional remediation and bioremediation of contaminated sites usually involves the physical removal of pollutants or biological exposure with the help of microorganisms. Basic physical recovery strategies are expensive, non-specific, and often render the soil unsuitable for further use by disrupting the microenvironment. Due to these concerns, there has been increased interest in environmentally friendly and sustainable approaches, such as phytostabilization, phytoremediation and phytofiltration for cleaning contaminated sites. In this article, special attention is paid to the selection of highly productive genotypes of sugar sorghum for further use in phytoremediation of soils from heavy metals. Removal of heavy metals from the environment with the help of plants in the modern world is a very effective and highly profitable method. In this regard, the identification and study of promising plants is the basis of successful biotechnology. From this point of view, sorghum crops are attractive. They have properties such as resistance to extreme drought, heat and salt resistance

Enhanced phytoremediation of atrazine-contaminated soil by vetiver (Chrysopogon zizanioides L.) and associated bacteria.

The intensive and long-term use of atrazine (ATZ) has led to the contamination of agricultural soils and non-target organisms, posing a series of threats to human health through the transmission of the food chain. In this study, a 60-day greenhouse pot experiment was carried out to explore the phytoremediation by Chrysopogon zizanioides L. (vetiver). The uptake, accumulation, distribution, and removal of ATZ were investigated, and the degradation mechanisms were elucidated. The results showed that the growth of vetiver was inhibited in the first 10 days of the incubation; subsequently, the plant recovered rapidly with time going. Vetiver grass was capable of taking up ATZ from the soil, with root concentration factor ranging from 2.36 to 15.55, and translocating to the shoots, with shoot concentration factor ranging from 7.51 to 17.52. The dissipation of ATZ in the rhizosphere soil (97.51%) was significantly higher than that in the vetiver-unplanted soil (85.14%) at day 60. Metabolites were identified as hydroxyatrazine (HA), deethylatrazine (DEA), deisopropylatrazine (DIA), and didealkylatrazine (DDA) in the samples of the shoots and roots of vetiver as well as the soils treated with ATZ. HA, DEA, DIA, and DDA were reported first time as metabolites of ATZ in shoots and roots of vetiver grown in soil. The presence of vetiver changed the formation and distribution of the dealkylated products in the rhizosphere soil, which remarkably enhanced the occurrence of DEA, DIA, and DDA. Arthrobacter, Bradyrhizobium, Nocardioides, and Rhodococcus were the major atrazine-degrading bacterial genera, which might be responsible for ATZ degradation in the rhizosphere soil. Our findings suggested that vetiver grass can significantly promote ATZ degradation in the soil, and it could be a strategy for remediation of the atrazine-contaminated agricultural soil.

Calcium and L-glutamate present the opposite role in managing arsenic in barley

Arsenic contamination in agricultural soils has posed tremendous threat to sustainable crop production and human health via food chain. Calcium and Glutamate have been well-documented in metal(loid)s detoxification, but it is poorly understood how they regulate arsenic-induced toxicity to plants. In this study, the effect of glutamate and calcium at high concentration on arsenic toxicity and accumulation in barley seedling was accessed in terms of plant growth, photosynthetic efficacy, arsenic uptake, translocation and accumulation, antioxidant defense, nutrient uptake and the expression of As transporters. Our results have demonstrated that calcium could effectively ameliorate arsenic toxicity to barley seedlings, which is mainly attributed to its beneficial effect on increasing nutrient uptake, reducing the aboveground arsenic accumulation and enhancing antioxidative defense capacity. However, it is unexpected that glutamate considerably exacerbated the arsenic toxicity to barley seedlings. More importantly, for the first time, glutamate was observed to tremendously facilitate the root-to-shoot translocation of arsenic by 41.8- to 60.8-fold, leading to 90% of the total amount of As accumulating in barley shoots. The reason of this phenomenon can be well explained by the glutamate-triggered enormous upregulation of genes involved in arsenic uptake (HvPHT1;1, HvPHR2 and HvNIP3;2), reduction (HvHAC1;1), translocation (HvABCC7, HvNIP1;1 and HvNIP3;3) and intracellular sequestration (HvABCC1). These findings suggest that calcium and glutamate function as the opposite player in managing arsenic, with calcium being an effective alleviator of arsenic stress to ensure the safe production of crops; while glutamate being a highly efficient phytoextraction agent for phytoremediation of arsenate-contaminated soils.

Oxidative Stress Response and Metal Transport in Roots of Macleaya cordata Exposed to Lead and Zinc.

Heavy metal pollution possesses potential hazards to plant, animal and human health, which has become the focus of recent attention. Hence, phytoremediation has been regarded as one of the most important remediation technologies for heavy-metal-contaminated soils. In this research, a dominant mine tailing plant, Macleaya cordata, was used as the experimental material to compare the metal transport and oxidative stress response in its roots under lead (Pb) and zinc (Zn) treatments. The result showed that Pb was mainly accumulated in the roots of M. cordata under the Pb treatment; less than 1% Pb was transported to the parts above. An analysis of the Zn content demonstrated a 39% accumulation in the shoots. The production of reactive oxygen species was detected using the in situ histological staining of roots, which showed that hydrogen peroxide in the root tips was observed to increase with the increase in both Pb and Zn concentrations. No significant superoxide anion changes were noted in the root tips under the Pb treatment. An analysis of the root enzyme activity showed that increase in NADPH oxidase activity can be responsible for the production of superoxide anions, subsequent the inhibition of root growth and decrease in antioxidant enzyme activities in the roots of M. cordata exposed to excess Zn. In total, this research provides evidence that the root of M. cordata has a high antioxidant capacity for Pb stress, so it can accumulate more Pb without oxidative damage. On the other hand, the Zn accumulated in the roots of M. cordata causes oxidative damage to the root tips, which can stimulate more Zn transport to the shoots to reduce the damage to the roots. This result will provide a basis for the application of M. cordata in the phytoremediation of soil polluted by Pb-Zn compounds.

Phytoaccumulation of zinc and its associated impact on the growth performance and tolerance index of six non-food crop plants grown in Zn-contaminated soil.

Crop plant remediation and detoxification of Zn-contaminated soils may pose a significant threat to food safety and, thus, human health. Therefore, the current study was carried out to assess the ability of six non-food crop plants (NFCP); Zea mays L. cultivar 360 (T360), Z. mays cultivar 123 (T123), Helianthus annuus L., Brassica juncea (L.) Czern., Ricinus communis L., and Simmondsia chinensis (Link) C.K. Schneid to remediate and restore Zn-contaminated soils. The investigated plants tolerate 150mg/kg of Zn content of the soil, where they had tolerance index (TI) > 1 for all growth criteria, except the root dry weight (DW) of S. chinensis. Z. mays T123 and R. communis were the most susceptible plants, while B. juncea and S. chinensis were moderately tolerant, while H. annuus was the most tolerant to high Zn concentrations in a growing medium. Increasing the soil Zn content led to a significant increase (p < 0.05) in Zn concentration in the various tissues of the six NFCPs. The studied NFCP did not translocate Zn to their grains/seeds; consequently, they can be used safely for Zn-contaminated soils. The Zn content in root and shoot was negatively correlated with the TI of their length and weight, while the translocation factor (TF) of Zn from root to shoot was positively correlated to the TI of the root length and weight. The six studied NFCPs were arranged based on their phytoremediation efficiency as follows: B. juncea (31.86%) > Z. mays T123 (31.14%) > Z. mays T360 (27.59%) > H. annuus (20.85%) > S. chinensis (20.29%) > R. communis (15.3%). All tested NFCPs accumulated significant concentrations of Zn in their roots and shoots, a high Zn uptake potential, and biomass at 150-450mg/kg of Zn treatments, indicating that these plants are good candidates for the implementation of a new strategy of cultivating NFCP for phytoremediation of Zn-contaminated soils.

Auxin alleviates cadmium toxicity by increasing vacuolar compartmentalization and decreasing long-distance translocation of cadmium in Poa pratensis

Kentucky bluegrass (Poa pratensis L.) hyperaccumulates cadmium (Cd) and exhibits a hypertolerance. Thus, it has potential for the phytoremediation of Cd-containing soil. Auxin signaling is involved in the response to Cd stress. However, the mechanisms of auxin-mediated detoxification and Cd translocation in plants remain unclear. This study aimed to investigate the effects of exogenous application of indole-3-acetic acid (IAA) on the Cd translocation, subcellular Cd distribution, chemical forms of Cd, and transcriptional regulation of Kentucky bluegrass. The results showed that the exogenous application of IAA increased the amount of organelle-bound Cd and vacuole-compartmentalized Cd in root cells, reduced the Cd concentration in the leaf tissues (epidermis, mesophyll, and vascular bundle) and root tissues (rhizodermis and cortex) but increased in the stele, and alleviate Cd-induced leaf chlorosis and growth inhibition. The expression of genes associated with Cd transporters (ABCs, ZIPs, NASs, OPTs, and YSLs), phosphatases, oxalate decarboxylases and lignin biosynthesis were significantly regulated by exogenous IAA under Cd stress. A positive regulation of phosphatases and oxalate decarboxylases genes related to an increase in phosphate- and oxalate-bound Cd, as well as a decrease in pectate- and protein-bound Cd and inorganic Cd, thereby contributing to a decrease in Cd phytotoxicity. The significant regulation of Cd transporters associated with decreasing the long-distance translocation of Cd, and the activation of lignin biosynthesis may contribute to the development of root endodermal barriers and increase the deposition of undissolved Cd phosphates and oxalate-bound Cd in the stele. These results revealed the important role of auxin in Cd detoxification and translocation in Kentucky bluegrass and they provide a theoretical basis for the phytoremediation of Cd-containing soil.

Phytoremediation assessment of Euphorbia granulata from 10 remote areas with different local climates and heavy metals composition

Phytoremediation technology is considered ecofriendly, economical and effective technique to manage contaminated sites. Identification of plants with better phytoremediation capacity is important. Euphorbia granulata was assessed for the uptake of Pb, Hg, Ni, Cr, Cd, As, Sn, Mo, Ag and Co in natural habitats from geographically remote 10 sites. Plant and representative soil samples were analyzed for heavy metals (HMs). Phytoremediation feasibility was evaluated on the basis of: 1) the average level of each HM by the plant; 2) Bioaccumulation coefficients (BACs); 3) Translocation factor (TF); 4) combinations analysis of BACs and TF for every HM. Tin was not absorbed while Pb, Cr, Cd, As, Ag and Co were accumulated in concentrations lesser than present the soil concentration (BACs < 1). Molybdenum and nickel had equal levels in both plant and soil (BACs = 1). However, Hg was stockpiled in higher concentrations by the plant compared to soil (BACs > 1). Lead, chromium, cadmium, arsenic, silver, cobalt, nickel and molybdenum were transferred with TF < 1 while Hg with > 1. The overall results revealed that E. granulata is an efficient Hg accumulator and can be employed for phytoremediation in soils contaminated with Hg.

Enhanced dandelion phytoremediation of Cd-contaminated soil assisted by tea saponin and plant growth-promoting rhizobacteria

Enhanced dandelion phytoremediation of Cd-contaminated soil assisted by tea saponin and plant growth-promoting rhizobacteria

Natural and Technical Phytoremediation of Oil-Contaminated Soil.

Natural and technical phytoremediation approaches were compared for their efficacy in decontaminating oil-polluted soil. We examined 20 oil-contaminated sites of 800 to 12,000 m2 each, with different contamination types (fresh or aged) and levels (4.2-27.4 g/kg). The study was conducted on a field scale in the industrial and adjacent areas of a petroleum refinery. Technical remediation with alfalfa (Medicago sativa L.), ryegrass (Lolium perenne L.), nitrogen fertilizer, and soil agrotechnical treatment was used to clean up 10 sites contaminated by oil hydrocarbons (average concentration, 13.7 g/kg). In technical phytoremediation, the per-year decontamination of soil was as high as 72-90%, whereas in natural phytoremediation (natural attenuation with native vegetation) at 10 other oil-contaminated sites, per-year decontamination was as high as that only after 5 years. Rhizodegradation is supposed as the principal mechanisms of both phytoremediation approaches.

Effects of single and combined applications of three root exudates of Sedum plumbizincicola on the phytoremediation efficiency of paddy soil contaminated with Cd

Root exudates are carriers for the transfer of material, energy and information between plant roots and soils. Plants encountering environmental stresses such as heavy metal pollution adapt to the environment by producing and secreting root exudates. In this study, laboratory soil culture experiment and pot experiment with Sedum plumbizincicola were used to study the effects of single and combined application of three root exudates, citric acid, glycine, and fructose, on the Cd-activation and phytoremediation of Cd-contaminated paddy soil. Results from the soil culture experiment showed that for the single application of root exudates, all three root exudates significantly activated the Cd in soil as presented by the increased content of diethylenetriamine pentaacetic acid extracted Cd (DTPA-Cd). In Particular, citric acid (SC) at a relatively low concentration (2 mmol/kg) exhibited the best Cd activation efficiency by increasing DTPA-Cd in the soil by 66.12%. For the combined application of root exudates, citric acid in combination with glycine (SC + G, 1:3) had the best activation effect on the Cd in the soil. In the phytoremediation pot experiment, both the single application of citric acid at a low concentrate (1 mmol/kg) and the combined application of citric acid and glycine (1:1) significantly reduced the total Cd and DTPA-Cd in the soil and increased the biomass and the content of Cd in S. plumbizincicola; thus, the phytoremediation efficiency of Cd-contaminated soil increased by 42.33% and 35.61%. The results from this study suggest that citric acid plays a crucial role in Cd activation and phytoremediation with single or combined applications with glycine. However, the mechanisms under the synergetic interaction between citric acid and glycine require further investigation.

Effect of Zinc Excess in Substrate on Physiological Responses of Sinapis alba L.

Zinc (Zn) is a fundamental micronutrient for plants' metabolism, but in high concentrations, it is toxic. In this study, we investigated the physiological response of white mustard (Sinapis alba L. cv. Belgia) plants to the Zn excess concentrations (50, 100, and 150 mg kg-1) in the substrate. The results showed that sand Zn concentration of 50 mg kg-1 did not affect the physiological parameters of plants, despite to the high Zn accumulation in shoots. The growth, biomass accumulation, photosynthesis rate, and pigment amount were inhibited at Zn concentrations of 100 and 150 mg kg-1 in substrate. A slight increase in malondialdehyde (MDA) was also observed at zinc concentrations (100 and 150 mg kg-1) without changes in membrane permeability, which is partly connectedtoan increase in the proline content. The results suggested that white mustard tolerates Zn excess impact. S. alba is able to grow on Zn-contaminated substrates along with significant Zn accumulation in shoots, which supports its high potential for phytoremediation of Zn-polluted agricultural soils. It is also possible to propose the following recycling of white mustard plants for Zn fortification feedstuff.

The bioaccumulation potential of heavy metals by Gliricidia sepium (Fabaceae) in mine tailings.

As a result of mining activities, waste of different types is generated. One example is mine tailings that contain potentially toxic elements such as heavy metals that negatively impact the environment and human health. Hence, developing treatments to guarantee its efficient elimination from the environment is necessary. Among these treatments, phytoremediation takes advantage of the potential of different plant species, to remove heavy metals from polluted sites. Gliricidia sepium is a tree that grows up to 15m high and distributed from southern Mexico to Central America. This study evaluates the heavy metal bioaccumulation capacity in roots and leaves, and the effect of such bioaccumulation on fifteen macro- and one micro-morphological characters of G. sepium growing during 360days in control, and in mine tailing substrates. G. sepium individuals growing on the exposed substrate registered the following average heavy metal bioaccumulation pattern in the roots: Fe > Pb > Zn > Cu, while in the leaf tissue, the bioaccumulation pattern was Cu > Fe > Pb > Zn. Macro- and micro-morphological characters evaluated in G. sepium decreased in plants exposed to metals. The translocation factor showed that Cu and Pb registered average values greater than 1. In conclusion, G. sepium is a species with potential for the phytoremediation of soils contaminated with Fe, Cu, and Pb, and for phytostabilizing soils polluted with Fe, Pb, Zn, and Cu, along with its ability to establish itself and turn into an abundant plant species in polluted sites, its capacity to bioaccumulate heavy metals in roots and leaves, and its high rate of HM translocation.