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Euphorbia hirta is used traditionally for medicinal purposes. A vast stretch of land in West Bengal is arsenic affected, where agricultural activities present the hazard of arsenic entering the food chain putting the entire community at health risk. The present work tried to study if these areas could be safely utilized to grow this medicinal plant. In this study, the medicinal plant Euphorbia hirta and a known hyperaccumulator Brassica juncea were exposed to a high level of arsenic, and after a certain span of time, arsenic translocation in both the plants was checked. The data revealed that Euphorbia hirta is not a hyperaccumulator and does not translocate high levels of arsenic to the aerial parts of the plant as compared to Brassica juncea. It was also found that the biochemical and genetic effects of arsenic stress were enhanced significantly more in Brassica juncea than in Euphorbia hirta. Thus, the present study points to the growth potential of the common medicinal weed Euphorbia hirta in the arsenic-affected areas without being a cause of human health concern., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Arsenic is a widespread toxic metalloid that is classified as a class I carcinogen known to cause adverse health effects in humans. In the present study, we investigated arsenic accumulation potential and comparative gene expression in Indian mustard. The amount of arsenic accumulated in shoots varied in the range of 15.99-1138.70 mg/kg on a dry weight basis among five cultivars. Comparative expression analysis revealed 10 870 significantly differentially expressed genes mostly belonging to response to stress, metabolic processes, signal transduction, transporter activity, and transcription regulator activity to be up-regulated, while most of the genes involved in photosynthesis, developmental processes, and cell growth were found to be down-regulated in arsenic-treated tissues. Further, pathway analysis using the KEGG Automated Annotation server (KAAS) revealed a large-scale reprogramming of genes involved in genetic and environmental information processing pathways. Top pathways with maximum KEGG orthology hits included carbon metabolism (2.5%), biosynthesis of amino acids (2.1%), plant hormone signal transduction (1.4%), and glutathione metabolism (0.6%). A transcriptomic investigation to understand the arsenic accumulation and detoxification in Indian mustard will not only help to improve its phytoremediation efficiency but also add to the control measures required to check bioaccumulation of arsenic in the food chain.

The phytoaccummulation of arsenic by Brassica juncea (L.) was investigated for varying concentrations selected within the range that is evident in Bangladeshi soil. B. juncea (Rai and BARI-11) was grown in the hydroponic media under greenhouse condition with different concentrations (0.5, 1.0, 15, 30, 50 and 100 ppm) of sodium arsenite. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was used to analyze the data. Mapping of potential area of phytoaccumulation of arsenic by B. juncea was done using Geographic information system (GIS). Arsenic was detected at lower concentrations (0.5 and 1.0 ppm) only at root system of the plant. For higher concentrations (15, 30, and 50 ppm) arsenic was detected both in the root and shoot systems. The results suggested that at 15 and 50 ppm uptake was higher compared to 30 ppm. For 100 ppm of arsenic no plant growth was observed. In Bangladesh, where concentration of arsenic is at lower level and present only at rooting zone, B. juncea may be used for phytoaccumulation of arsenic keeping usual agronomic practices. However, for higher concentrations, B. juncea can be regarded as a good accumulator of arsenic where uptake of arsenic was up to 1% of total biomass of the plant.

Arsenic (As), a non-essential metalloid, severely affects the normal functioning of plants, animals and humans. Plants play a crucial role in metabolic, physiological and numerous detoxification mechanisms to cope up with As induced stress. This study aimed to examine the differential response in two Brassica juncea cultivars, Varuna and Pusa Jagannath (PJn) exposed to different doses of As (50, 150, 300 μM) for 48 h duration. Change in morphological traits, concentration of individual as well as total GSL, sulfur related thiol proteins, sulfur content, and phytochemicals were analyzed in both cultivars. Accumulation pattern of As showed dose dependent accumulation in both the cultivars, being more in PJn. Our finding revealed that both cultivars were tolerant at low concentrations of As, while at higher concentration Varuna excelled over PJn. The increased tolerance of Varuna cultivar exposed to 150 and 300 μM concentration of As, correlated with its increased thiol related proteins, sulfur content and phytochemicals, which serves as defence strategy in the plant against oxidative stress. Differential pattern of total as well as individual GSLs content was observed in both Varuna and PJn cultivars. Varuna cultivar showed higher level of total and aliphatic GSLs, which serves as defence compound with other detoxification machineries to combat As stress. Our findings provide foundation for developing metalloid tolerant crops by analyzing the role of different genes involved in GSL mechanism and signaling pathways in different organs of plant., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Arsenic (As) is an emerging pollutant causing inhibition in growth and development of plants resulting into phytotoxicity. On the other hand, silicon (Si) has been suggested as a modulator in abiotic and biotic stresses that, enhances plant's physiological adaptations in response to several stresses including heavy metal stress. In this study, we used roots of hydroponically grown 14 day old seedlings of Brassica juncea var. Varuna treated with 150 μM As, 1.5 mM Si and both in combination for 96 h duration. Application of Si modulated the effect of As by improving morphological traits of root along with the development of both primary and lateral roots. Changes observed in root traits showed positive correlation with As induced cell death, accumulation of reactive oxygen species (ROS), nitric oxide (NO) and intracellular superoxide radicals (O2(-)). Addition of 1.5 mM Si during As stress increased accumulation of As in roots. Mineral nutrient analysis was done using energy-dispersive X-ray fluorescence (EDXRF) technique and positively correlated with increased cysteine, proline, MDA, H2O2 and activity of antioxidant enzymes (SOD, CAT and APX). The results obtained from the above biochemical approaches support the protective and active role of Si in the regulation of As stress through the changes in root developmental process., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Brassica juncea (Indian mustard) L. plants were exposed to different concentrations (0.0, 0.1, 0.2 and 0.3mM) of arsenic (V) and harvested after 30 and 60 days of sowing for the analysis of growth parameters, metal uptake, brassinosteroids (BRs) synthesis and oxidative stress markers. As (V) significantly hampered the growth of B. juncea plants and triggered the modulations of various stress markers like proteins, antioxidative enzymes (SOD, CAT, POD, APX, GR, MDHAR and DHAR) and MDA content. Furthermore, As (V) induced the synthesis of 4 BRs, castasterone, teasterone, 24-epibrassinolide, and typhasterol, which were isolated and characterized by gas chromatography-mass spectrometry (GC-MS). The study further highlig5895hted the significant uptake of arsenic ions by mustard plants., (Copyright © 2015 Elsevier Inc. All rights reserved.)

An arsenic hypertolerant bacterium was isolated from arsenic contaminated site of West Bengal, India. The bacteria was identified as Staphylococcus arlettae strain NBRIEAG-6, based on 16S rDNA analysis. S. arlettae was able to remove arsenic from liquid media and possesses arsC gene, gene responsible for arsenate reductase activity. The biochemical profiling of the isolated strain showed that it had the capacity of producing indole acetic acid (IAA), siderophores and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase. Furthermore, an experiment was conducted to test the effect of S. arlettae inoculation on concurrent plant growth promotion and arsenic uptake in Indian mustard plant [Brassica juncea (L.) Czern. Var. R-46] when grown in arsenic spiked (5, 10 and 15 mg kg(-1)) soil. The microbial inoculation significantly (p<0.05) increased biomass, protein, chlorophyll and carotenoids contents in test plant. Moreover, as compared to the non-inoculated control, the As concentration in shoot and root of inoculated plants were increased from 3.73 to 34.16% and 87.35 to 99.93%, respectively. The experimental results show that the plant growth promoting bacteria NBRIEAG-6 has the ability to help B. juncea to accumulate As maximally in plant root, and therefore it can be accounted as a new bacteria for As phytostabilization., (Copyright © 2012 Elsevier B.V. All rights reserved.)

In this study, the Geo-accumulation index (Igeo), Human Health Risk Assessment (HRA), and Ecological Risk Index (ERI) were utilized to examine the risks associated with the soils at the DaeyangYeongseong mine. Brassica juncea and Raphanus sativus were employed in the ecological toxicity test. In all soil samples, the mean Igeo value of arsenic measured 3.15, and cadmium measured 6.63, indicating a very high level of heavy metal contamination. The carcinogenic risk of cadmium and arsenic for adults was 4.30×10−3 and 1.43×10−5, respectively. For children, these values were 3.92 × 10−2 and 1.33 ×10−4, exceeding the acceptable level (1×10−6). In all soils, cadmium showed extremely high ecological risk levels, and arsenic had extremely high risk levels in 34.8% of the total area. This was also confirmed in toxicity assessments using plants. Therefore, arsenic and cadmium were found to be the main causes of soil contamination and ecological risk. [ABSTRACT FROM AUTHOR]

The idea of a critical limit (CL) of nutritional elements distinguishes deficiency from adequacy, which could suggest fertilizer administration. The critical limit can be used to distinguish between responsive (deficiency) and non-responsive (sufficiency) sites. The study aims to estimate the critical limit of phosphorus (P) for mustard and maize in different Agro-ecological Zones (AEZs) of Bangladesh. In this context, the study was conducted in 20 types of soil and two crops (maize and mustard) both in pot and field experiments. Twenty soils from different places were used as experimental materials, among them 12 soil samples had inadequate soil fertility, 4 had low fertility, and the remaining 4 had medium levels of fertility. The treatments were two crops: BARI Hybrid Maize 7 (Maize) and BINA Sharisha 9 (Mustard) and two levels of phosphorus (P): 0 and 15 ppm. Dry matter (DM) yield was calculated and the nutritional content of plant samples was determined. Depending on the chemical properties of the soil, the results ranged from extremely low to very high levels. Reading the mustard crop, the estimated critical levels of P were found to be 14.8 ppm (graphical) and 18.9 ppm (statistical). Regarding the maize crop, the estimated critical P levels were found to be 14.5 ppm (graphical) and 12.3 ppm (statistical). When soil P is less than the CL, plants respond to P-based fertilizer effectively. The results of the trials will assist in managing P fertilizer for the sustainability of maize and mustard production in diverse soil types in different agroecological zones of Bangladesh. [ABSTRACT FROM AUTHOR]

In the current study, we successfully synthesized the zinc oxide nanoparticles (ZnO-NPs) via an efficient, facile, and cost-effective method of the modified hydrothermal synthesis approach, and examined their effectiveness in alleviating arsenic (As) stress in Brassica juncea. The synthesized ZnO-NPs were analyzed using a variety of experimental techniques viz. XRDs, SEM micrographs, EDAX/Mapping pattern, Raman Spectroscopy Pattern, and X-ray photoemission spectroscopy analysis. All of these analyses revealed that ZnO-NPs were highly pure with no internal defects and could potentially be used in plant applications. Hence, we further determined the effect of these nanoparticles in modulation of As tolerance in B. juncea plants by examining the various growth attributes, photosynthesis parameters, antioxidant activities, and enzyme activities. Our results demonstrated that As-stress inhibited growth, photosynthesis-related parameters, reduced protein content, as well as carbonic anhydrase, nitrate reductase, and RuBisCO; however, these attributes were substantially up-regulated by the supply of ZnO-NPs to the leaves. Furthermore, As stress-induced increases in malondialdehyde and H 2 O 2 levels are partially reversed by ZnO-NP in the As-stressed plants. Overall, supplementation positively regulated As tolerance in B. juncea by altering the key enzymes involved in ROS detoxification, which in turn prevented As-induced oxidative damage to the plant tissues. Hence, our study clarified the potential involvement of the newly synthesized ZnO-NPs in alleviating As stress in plants. Furthermore, this is the first report to elucidate the effect of the ZnO-NPs synthesized by the hydrothermal reaction route on As-stress modulation in B. juncea. [Display omitted] • Arsenic (As) stress affects growth and biomass yield in mustard plants. • As toxicity decreased pigment system and alters biochemical attributes and antioxidants. • Supplementation of zinc oxide nanoparticles (ZnO-NPs) enhanced growth and protects pigments. • ZnO-NPs regulates antioxidant system and As uptake in mustard. [ABSTRACT FROM AUTHOR]

Phytoremediation is an environment-friendly method for toxic elements remediation. The aim of this study was to improve the phytoremediation efficiency of Brassica juncea and the rhizosphere soil micro-ecology in cadmium (Cd) and arsenic (As) contaminated soil. A field experiment was conducted with six treatments, including a control treatment (CK), two treatments with two contents of Trichoderma harzianum (T1: 4.5 g m−2; T2: 9 g m−2), one biochar treatment (B: 750 g m−2), and two combined treatments of T1B and T2B. The results showed Trichoderma harzianum promoted the total chlorophyll and translocation factor of Brassica juncea, while biochar promoted plant biomass compared to CK. T2B treatment showed the best results, which significantly increased Cd accumulation by 187.49–308.92%, and As accumulation by 125.74–221.43%. As a result, the soil's total Cd content was reduced by 19.04% to 49.64% and total As contents by 38.76% to 53.77%. The combined amendment increased the contents of soil available potassium, phosphorus, nitrogen, and organic matter. Meanwhile, both the activity of glutathione and peroxidase enzymes in plants, together with urease and sucrase enzymes in soil, were increased. Firmicutes (dominant bacterial phylum) and Ascomycota (dominant fungal phylum) showed positive and close correlation with soil nutrients and plant potentially toxic elements contents. This study demonstrated that phytoremediation assisted by biochar and Trichoderma harzianum is an effective method of soil remediation and provides a new strategy for enhancing plant remediation efficiency. [ABSTRACT FROM AUTHOR]

Arsenic (As) is one of the most common inorganic pollutants; unfortunately, it is also one of the most toxic and is therefore a cause of great concern for the health risks that could result from it. Removing arsenic from the soil using phytoremediation approaches is an effective strategy, and several studies demonstrate the ability of Cannabis sativa (TSN 19109, hemp) to tolerate this harmful contaminant. The aim of this work was to identify the best experimental conditions for a phytoremediation plan to be applied in a disused area located in Sicily (Italy) and contaminated by As, comparing Cannabis sativa with Brassica juncea (TSN 23059) and Zea mays (TSN 42269, corn). To assist the process, several chelating agents were tested to improve arsenic mobility, and two different sets of arsenic-tolerant bacteria were isolated from the rhizospheric soil of indigenous herbaceous species and used to promote plant growth, leading to a significant improvement in terms of biomass produced and phytoextraction. After the combined treatment, the arsenic content in the aerial part of the plants increased by more than two orders of magnitude (e.g., from 0.05 to 6.57 mg kg−1, from 0.04 to 6.69 mg kg−1, and from 0.03 to 5.57 mg kg−1 for brassica, corn, and hemp, respectively), confirming the marked increase in the total absorption of As by plants. [ABSTRACT FROM AUTHOR]

Objective: Arsenic (As) has been in the forefront of toxicological research due to its continual worldwide human exposure and its adverse effects including genotoxicity. The study assessed the potential ameliorative effect of Indian mustard seeds (Brassica juncea) and their nanoparticles against arsenic toxicity. Methods: Male Wistar rats were used for the exposure study. Group I was control and group V was exposed only to the nanoparticles. Groups II, III, and IV were exposed to 10 mg/kg sodium arsenite for two weeks. Groups III and IV were treated with mustard seeds and the nanoparticles (500 mg/kg) respectively. Results: Arsenic intoxication caused a marked increase in the levels of As in the brain. Additionally, oxidative damage was exhibited with significantly enhanced levels of serum 8-OHdG and hepatic p53 and pS15. The pictographs and the analyzed parameters of the COMET assay illustrated DNA damage with significantly increased values of tail moment and length. Treatment with mustard seeds and its nanoparticles markedly reversed the adverse effects of As toxicity, which is attributed to the presence of a gamut of constituent phytocompounds in the mustard seeds. Conclusion: Taken together the nano formulation was more efficacious and could be introduced as a potential nutraceutical to combat metal toxicity.

Forty-day-old Brassica juncea (var. Pusa Jai Kisan) plants were exposed to arsenic (As, 250 µM Na2HAsO4·7H2O) stress. The ameliorative role of ferrous sulfate (2 mM, FeSO4·7H2O, herein FeSO4) was evaluated at 7 days after treatment (7 DAT) and 14 DAT. Whereas, As induced high magnitude oxidative stress, FeSO4 limited it. In general, As decreased the growth and photosynthetic parameters less when in the presence of FeSO4. Furthermore, components of the antioxidant system operated in better coordination with FeSO4. Contents of non-protein thiols and phytochelatins were higher with the supply of FeSO4. Blue-Native polyacrylamide gel electrophoresis revealed an As-induced decrease in almost every multi-protein-pigment complex (MPC), and an increase in PSII subcomplex, LHCII monomers and free proteins. FeSO4 supplication helped in the retention of a better stoichiometry of light-harvesting complexes and stabilized every MPC, including supra-molecular complexes, PSI/PSII core dimer/ATP Synthase, Cytochrome b6/f dimer and LHCII dimer. FeSO4 strengthened the plant defence, perhaps by channelizing iron (Fe) and sulfur (S) to biosynthetic and anabolic pathways. Such metabolism could improve levels of antioxidant enzymes, and the contents of glutathione, and phytochelatins. Important key support might be extended to the chloroplast through better supply of Fe-S clusters. Therefore, our results suggest the importance of both iron and sulfur to combat As-induced stress in the Indian mustard plant at biochemical and molecular levels through enhanced antioxidant potential and proteomic adjustments in the photosynthetic apparatus. [ABSTRACT FROM AUTHOR]

Arsenic (As) stress provokes various toxic effects in plants that disturbs its photosynthetic potential and hampers growth. Ethylene and selenium (Se) have shown regulatory interaction in plants for metal tolerance; however, their synergism in As tolerance through modification of the antioxidant enzymes and hormone biosynthesis needs further elaboration. With this in view, we investigated the impact of ethylene and Se in the protection of photosynthetic performance against As stress in mustard (Brassica juncea L.). Supplementation with ethephon (2-chloroethylphosphonic acid; ethylene source) and/or Se allayed the negative impact of As-induced toxicity by limiting As content in leaves, enhancing the antioxidant defense system, and decreasing the accumulation of abscisic acid (ABA). Ethylene plus Se more prominently regulated stomatal behavior, improved photosynthetic capacity, and mitigated As-induced effects. Ethephon in the presence of Se decreased stress ethylene formation and ABA accumulation under As stress, resulting in improved photosynthesis and growth through enhanced reduced glutathione (GSH) synthesis, which in turn reduced the oxidative stress. In both As-stressed and non-stressed plants treated with ethylene action inhibitor, norbornadiene, resulted in increased ABA and oxidative stress with reduced photosynthetic activity by downregulating expression of ascorbate peroxidase and glutathione reductase, suggesting the involvement of ethylene in the reversal of As-induced toxicity. These findings suggest that ethephon and Se induce regulatory interaction between ethylene, ABA accumulation, and GSH metabolism through regulating the activity and expression of antioxidant enzymes. Thus, in an economically important crop (mustard), the severity of As stress could be reduced through the supplementation of both ethylene and Se that coordinate for maximum stress alleviation. [ABSTRACT FROM AUTHOR]

Phytoremediation represents a natural method to remove contaminants from soil. The goal of this study was to investigate the potential of phosphate-assisted phytoremediation by two energy crops, Cannabis sativa L. and Brassica juncea L., for the sustainable remediation of heavily arsenic-contaminated industrial soil. The two species were investigated for uptake, translocation, and physiological effects of arsenic and phosphate in a microcosm test. Although C. sativa and B. juncea were symptomless when grown in arsenic-contaminated soil, an important reduction of biomass (50 and 25%, respectively) was observed as a stress marker. Phytotoxicity and cytotoxicity effects promoted by contaminated soils were investigated in both the species and a model plant for ecotoxicity studies, Vicia faba L., which is the most developed model to test genotoxicity effects in terms of chromosomal aberration and micronuclei presence. The higher amount of arsenic was found in C. sativa and B. juncea roots (on average 1473 and 778 mg kg−1, respectively), but both species were able to uptake and translocate arsenic in leaves and stems, up to 47.0 and 189 mg kg−1, respectively. Phosphate treatment had no effect on arsenic uptake in none of the crop, but significantly improved the plant performance. Biomass production resulted similar to that of B. juncea control plants. Antioxidant enzymatic activities and photosynthetic performance responded differently in the two crops. The present investigation provides new insight for a proficient selection of the most suitable crop species for sustainable phytomanagement of a highly polluted As-contaminated site by coupled phytoremediation-bioenergy approach. [ABSTRACT FROM AUTHOR]

Among the toxic heavy metal(loid)s, cadmium (Cd) and arsenic (As) have devastating effects on crop productivity and human health. In plants, mechanisms of detoxification of Cd and As proceed via a glutathione (GSH) dependent common pathway, despite their different modes of toxicity. In this context, the present study aimed to investigate how the common detoxification mechanisms for Cd and As influence the physiological and biochemical responses of seedlings of an important plant used for phytoremediation purposes, Brassica juncea, under Cd and As stress.We demonstrated that Cd and As trigger mostly distinct, but partly overlapping, responses in B. juncea. Exposure of B. juncea seedlings to 100 µM Cd stress for 12 days in a hydroponic system led to a significant reduction in the growth of roots and shoots, and in total chlorophyll content. However, As stress caused a decline in root length only. High-performance liquid chromatography analyses revealed a significant increase in cysteine levels in roots and shoots in response to As stress compared with control and Cd-treated plants. Concomitant elevated sulfur content in response to As stress was observed in roots and shoots. In terms of GSH content, Cd and As triggered similar responses, with a significant decrease in GSH in roots, and non-significant changes in shoots, compared with untreated plants. Inductively coupled plasma-atomic emission spectroscopy revealed that under Cd stress, plants preferentially accumulated zinc (Zn) in the roots compared with iron (Fe) and manganese (Mn). Responses in roots under As and Cd stress were similar with respect to Fe accumulation but opposite in terms of Zn and Mn accumulation. Our data provide valuable insights for design of future strategies for sustainable plant growth on As and Cd polluted soils. [ABSTRACT FROM AUTHOR]

With the increasing pollution in today's world, importance is being given to solve a problem and do it in a sustainable, ecofriendly manner. Arsenic is a class-1 carcinogen and also causes many other side effects to humans, plants and animals. The utilization of arsenic as wood preservatives, pesticides, or its historical overuse by some military units for rice killing operations has led to the increase in the toxic effects of arsenic like its carcinogenicity, decreased immune response etc. Although conventional methods like coagulation, lime softening, adsorption, membrane technology are effective, they have their disadvantages like additional waste generation, causing increased pollution and are expensive. The better alternative is phytoremediation. Appropriate plants like Brassica juncea, Hydrilla verticilata, Pteris vittata L., Vallisneria natans, can be chosen based on the method of the remediation like phytoextraction, phytostabilization and phytofiltration or phytovoltalization. This review provides the list of a few plants which can be likely chosen for the purpose of both water and soil remediation. Advancements are occurring in bioremediation studies with the development of transgenic plants like transgenic tobacco, transgenic Arabidopsis thaliana for better phytoremediation. Understanding the mechanism employed by the plant for its uptake/detoxification can aid in the enhancement of the process of remediation with the external supply of phosphorus. Along with this, the proper and safe disposal of plants is crucial for the remediation process. In addition, awareness of this solution to the general public is to be made for its effectiveness. [ABSTRACT FROM AUTHOR]

The interaction of mineral nutrients with metals/metalloids and signalling molecules is well known. In the present study, we investigated the effect of phosphorus (P) in mitigation of arsenic (As) stress in mustard (Brassica juncea L.).The study was conducted to investigate potential of 30 mg P·kg−1 soil P supplement (diammonium phosphate) to cope up with the adverse effects of As stress (24 mg As·kg−1 soil) in mustard plantsSupplementation of P influenced nitric oxide (NO) generation, which up‐regulated proline metabolism, ascorbate–glutathione system and glyoxalase system and alleviated the effects of on photosynthesis and growth. Arsenic stress generated ROS and methylglyoxal content was scavenged through P‐mediated NO, and reduced As translocation from roots to leaves. The involvement of NO under P‐mediated alleviation of As stress was substantiated with the use of cPTIO (NO biosynthesis inhibitor) and SNP (NO inducer). The reversal of P effects on photosynthesis under As stress with the use of cPTIO emphasized the role of P‐mediated NO in mitigation of As stress and protection of photosynthesisThe results suggested that P reversed As‐induced oxidative stress by modulation of NO formation, which regulated antioxidant machinery. Thus, P‐induced regulatory interaction between NO and reversal of As‐induced oxidative stress for the protection of photosynthesis may be suggested for sustainable crops. [ABSTRACT FROM AUTHOR]

The present study was designed to see the influence of selenium (Se) and sulphur (S) in the alleviation of arsenic (As)-induced stress in Brassica juncea plant. Se-induced alterations in physiological and biochemical responses due to deficient S (DS), normal S (NS) and additional S (AS) conditions were evaluated in 14-day-old seedlings of B. juncea variety Varuna. During the last 7 days of the 14-day-old seedlings, supplementation with arsenite (AsIII, 300 μM) alone and its combination with selenite (SeIV, 50 μM) along with different S treatments was done which are as follows: (i) control; (ii) As; (iii) As+Se+DS; (iv) As+Se + NS; (v) As+Se + AS. Experimental results showed that the application of AS in spite of NS supplied with Se influenced plant growth, oxidative stress and thiol-ascorbate-related parameters more prominently under As stress. The plants with As+Se+AS treatment exhibited lower ROS (superoxide and hydrogen peroxide ion), malondialdehyde (MDA) accumulation and lipoxygenase activity with increased activities of superoxide dismutase, catalase and ascorbate peroxidase compared with As+Se+NS condition. These plants also exhibited an increase in cysteine, non-protein thiols and phytochelatins, along with reduced, oxidised and redox content of glutathione and ascorbate. Furthermore, the application of S along with Se increased the activities of glutathione reductase, glutathione S-transferase, glutathione peroxidase, monodehydroascorbate and dehydroascorbate to minimise As stress. However, we observed that these responses were reversed under As+Se+DS condition and induced oxidative stress, which was almost similar to As only treatment. It indicated that AS nutrition potentiated Se to alleviate As-inhibited plant growth by modulating antioxidants including thiol-ascorbate-based mechanism and reducing As accumulation in B. juncea plants. [ABSTRACT FROM AUTHOR]

Plants have ability to adapt themselves through altering their growth process. In the present study, we examined exogenous application of nitric oxide (NO) on nitrogen metabolism and auxin (PIN) gene expression, and its possible role in alleviation of arsenic (As) toxicity in Brassica juncea seedlings. Seven days old hydroponically grown B. juncea seedlings were exposed to AsIII (150 μM), Sodium nitroprusside (NO donor, 100 μM), AsIII + SNP and control (without metal)for 48 h. Experimental results revealed that AsIII stress: enhanced the level of nitrite, NiR activity, NO 3 − and NH 4 +content as well as NADH-GOGAT activity; but GDH level decreased; enhanced content of amino acids; upregulated gene expression level of N metabolism and downregulated polar auxin transporter genes (PIN); inhibited plant growth and morphological parameters; increased MDA, H 2 O 2, cysteine, proline content, enzymatic antioxidants (SOD, CAT, APX; GSH, TT, NPT); and decreased nutrient content. AsIII + SNP combination reduced the accumulation of As; improved growth; chlorophyll, protein and mineral nutrient content by scavenging ROS generation; maintained amino acids content; downregulated expression of N metabolism genes and upregulated expression of auxin transporter (PIN) genes. Additional biochemical data depicts reduction in the level of nitrogen related enzymatic activities, and other stress related parameters. Overall, this study provides an integrated view that exogenous SNP (NO donor) supplementation alleviated the inhibitory role of AsIII in B. juncea seedlings by altering nutrients, amino acids and auxin redistribution via expression of nitrogen and PIN gene profiling. Image 1 • Sodium nitroprusside supplementation minimizes oxidative stress created by arsenic by neutralization of generated ROS in mustard seedlings. • Nutrient profiling showed improvement of nutrient content after Sodium nitroprusside addition during arsenic stress. • Sodium nitroprusside along with arsenic downregulates the expression of nitrogen uptake, assimilation genes and upregulate auxin transporter genes. • Interaction of arsenic and sodium nitroprusside provides an integrated view of plant response to change the plant metabolism through different cellular processes and improve the crop productivity. [ABSTRACT FROM AUTHOR]

The current study was carried out to investigate the role of exogenous sulphur (K 2 SO 4 : S; 60 mg S kg −1 sand) and calcium (CaCl 2 : Ca; 250 mg Ca kg −1 sand) individually as well as in combination (S + Ca) in ameliorating the inhibitory effect of As (Na 2 HAsO 4 ·7H 2 O: As 1 ; 15 mg As kg −1 sand and As 2 ; 30 mg As kg −1 sand) by analyzing biomass accumulation, mineral nutrients uptake, photosynthetic pigments content, redox status of the cell, enzymatic and non-enzymatic defense system in Brassica juncea L. seedlings. Biomass accumulation, uptake of mineral nutrients, photosynthetic pigments (chlorophyll a , b and carotenoids) content and the activity of proline dehydrogenase (ProDH) declined with increasing accumulation of As in root as well as leaves in As dose dependent manner. Contrary to this, exogenous application of S, Ca and S + Ca, markedly reduced the negative impact of As on above captioned traits except ProDH activity. On the other hand, ROS and their biomarkers (superoxide radical; O₂˙ˉ, hydrogen peroxide; H 2 O 2, malondialdehyde; MDA equivalents content and membrane damage; electrolyte leakage), activities of enzymatic (superoxide dismutase; SOD, peroxidase; POD, catalase; CAT and glutathione- S -transferase; GST) and non-enzymatic antioxidant i.e. proline (Pro) content and its enzyme pyrroline-5-carboxylate synthetase; P5CS activity were increased in root and leaves under As stress. While, exogenous application of S, Ca and S + Ca, further enhanced the activities of above mentioned enzymes and Pro content thereby causing considerable reduction in O₂˙ˉ, H 2 O 2 , MDA equivalents content and electrolyte leakage. This study suggests that exogenous application of S and/or Ca efficiently (particularly S + Ca) lowered the negative impact of As on biomass accumulation in Brassica seedlings by improving the uptake of essential mineral nutrients’, content of photosynthetic pigments, activities of enzymatic and content of non-enzymatic antioxidants. [ABSTRACT FROM AUTHOR]

Application of nanoparticles (NPs) is very effective in reducing metal toxicity. The present study was designed to determine the effectiveness of iron oxide nanoparticles (Fe3O4 NP) in reducing the toxicity of arsenic in Indian mustard (Brassica juncea var. Pusa Jagannath) plant. Fourteen-day-old mustard plants were subjected to 150 µM As(III), Fe3O4 NPs (500 mg L−1 Fe3O4), 500 mg L−1 FeSO4 or As(Ш) + Fe3O4 NPs (150 µM + 500 mg L−1) stress for a period of 96 h. Significant toxicity was observed in seed germination indicators, and root-shoot length under arsenic (As) stress, but application of Fe3O4 NPs along with As improved the overall growth of plant. Results demonstrated increased photosynthetic pigment and protein content under Fe3O4 NP augmentation as compared to As-alone treatment. Antioxidative enzymes such as SOD, CAT, APX and stress-related parameters (cysteine and proline) showed varied results under different treatments. However, decreased stress-related parameters might be due to restricted entry of As inside the plant in the presence of Fe3O4 NP, and hence detoxification machinery is not required. The ameliorating effect of Fe3O4 NPs in combination with As was confirmed by reduced MDA and H2O2 content. Further, the addition of Fe3O4 NPs along with As altered sulphur-related gene transcripts. Overall, this study suggests the possible involvement of Fe3O4 NPs as nano-adsorbents in reducing As toxicity in the plant through its size variation and increase/decrease of various study parameters. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) and arsenic (As) in co-contaminated soil can enter the human body harming health via the food chain, such as vegetables. Biochar derived from waste has been used to reduce heavy metal uptake by plant, but long-term effects of biochar under Cd and As co-contaminated soil needs to be investigated. A following mustard (Brassica juncea) was grown on co-contaminated soil amended with different raw materials of biochar including biochars pyrolyzed by lignite coal (LCB), rice straw (RSB), silkworm excrement (SEB), and sugar refinery sludge (SSB). The results showed that compared to the control, Cd and As contents of mustard shoot in SSB treatment decreased by 45–49% and 19–37% in two growing seasons, respectively, which was the most effective among 4 biochars. This probably due to SSB owns more abundant Fe-O functional groups. Biochar also altered the microbial community composition, specifically SSB increased proteobacteria abundance by 50% and 80% in the first and second growing seasons, thereby promoted the simultaneous immobilization of Cd and As in soils which may reduce the potential risks to humans. In summary, considering the long-term effects and security of SSB application on mustard, not only is it an effective waste recycle option, but it should also be promoted as a promising approach for safe vegetable production in Cd and As co-contaminated soils. [Display omitted] • Waste derived biochar reduced integrated Cd and As health risks. • Sugar refinery sludge biochar was optimal for simultaneous Cd and As remediation. • Biochar feedstocks differed in dominant fixing mechanisms. • Fe-O functional groups are important for As fixation. • Biochar positively affected soil microbial diversity and community structure. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a non-essential element, a groundwater pollutant, whose uptake by plants produces toxic effects. The use of As contaminated groundwater for irrigation can affect the crop productivity. Realizing the importace of the Brassica juncea as a crop plant in terms of oil-yield, there is a need to unravel mechanistic details of response to As stress and identify key functional genes and pathways. In this research, we studied time dependent (4 h to 96 h) transcriptome changes in roots and shoots of B. juncea under arsenate [As(V)] stress using Agilent platform. Among the whole transcriptome profiled genes, a total of 1,285 genes showed significant change in expression pattern upon As(V) exposure. The differentially expressed genes were categorized to various signaling pathways including hormones (jasmonate, abscisic acid (ABA), auxin and ethylene) and kinases. Significant effects were also noticed on genes related to sulfur, nitrogen, CHO, and lipid metabolisms along with photosynthesis. Biochemical assays were conducted using specific inhibitors of glutathione (GSH) and jasmonate biosynthesis, and kinases. The inhibitor studies revealed interconnection among sulfur metabolism, jasmonate and kinase signaling pathways. In addition, various transposons also constituted a part of the altered transcriptome. Lastly, we profiled a set of key functional up-

We wished to evaluate the effects of arsenic on the morphology and anatomy of Brassica oleracea , Raphanus sativus , Brassica juncea , Brassica oleracea var. capitata and Brassica oleracea var. italica . Seeds were subjected to concentrations 0 µM, 250 µM, 350 µM and 450 µM arsenic in the form of sodium arsenate (Na 2 HAsO 4 ·7H 2 O) during 12 days. All species accumulated more arsenic in the roots than in the shoots, except for B. oleracea var. capitata . There was no difference of translocation factor between species and treatments. Growth decrease was observed in roots of B. oleracea and R. sativus , and in shoots of R. sativus and B. oleracea var. italica . All species presented anatomical alterations in the roots, such as: cell hypertrophy, protoplast retraction, cellular plasmolysis, and necrotic regions. B. juncea presented collapse and hypertrophy of cells from the leaf blade tissues. Quantitative anatomical analyses performed on the root and leaves of B. oleracea and B. juncea revealed that arsenic interfered on the root vascular cylinder diameter and on height of epidermal cells of the adaxial leaf surface of both species. We concluded that arsenic was absorbed from the culture medium and induced alterations both on root and shoot growth of the seedlings. Retention of arsenic within the root was responsible for major damage in this organ. [ABSTRACT FROM AUTHOR]

Arsenic (As) is a non-essential element, a groundwater pollutant, whose uptake by plants produces toxic effects. The use of As-contaminated groundwater for irrigation can affect the crop productivity. Realizing the importance of the Brassica juncea as a crop plant in terms of oil-yield, there is a need to unravel mechanistic details of response to As stress and identify key functional genes and pathways. In this research, we studied time-dependent (4-96 h) transcriptome changes in roots and shoots of B. juncea under arsenate [As(V)] stress using Agilent platform. Among the whole transcriptome profiled genes, a total of 1,285 genes showed significant change in expression pattern upon As(V) exposure. The differentially expressed genes were categorized to various signaling pathways including hormones (jasmonate, abscisic acid, auxin, and ethylene) and kinases. Significant effects were also noticed on genes related to sulfur, nitrogen, CHO, and lipid metabolisms along with photosynthesis. Biochemical assays were conducted using specific inhibitors of glutathione and jasmonate biosynthesis, and kinases. The inhibitor studies revealed interconnection among sulfur metabolism, jasmonate, and kinase signaling pathways. In addition, various transposons also constituted a part of the altered transcriptome. Lastly, we profiled a set of key functional up- and down-regulated genes using real-time RT-PCR, which could act as an early indicators of the As stress. [ABSTRACT FROM AUTHOR]

Arsenic (As) is recognized as a toxic pollutant in soils of many countries. Since phosphorus (P) and sulphur (S) can influence arsenic mobility and bioavailability, as well as the plant tolerance to As, phytoremediation techniques employed to clean-up As-contaminated areas should consider the interaction between As and these two nutrients. In this study, the bioavailability and accumulation of arsenate in the species Brassica juncea were compared between soil system and hydroponics in relation to P and S concentration of the growth substrate. In one case, plants were grown in pots filled with soil containing 878 mg As kg. The addition of P to soil resulted in increased As desorption and significantly higher As accumulation in plants, with no effect on growth. The absence of toxic effects on plants was likely due to high S in soil, which could efficiently mitigate metal toxicity. In the hydroponic experiment, plants were grown with different combinations of As (0 or 100 μM) and P (56 or 112 μM). S at 400 μM was also added to the nutrient solution of control (−As) and As-treated plants, either individually or in combination with P. The addition of P reduced As uptake by plants, while high S resulted in higher As accumulation and lower P content. These results suggest that S can influence the interaction between P and As for the uptake by plants. The combined increase of P and S in the nutrient solution did not lead to higher accumulation of As, but enhanced As translocation from the root to the shoot. This aspect is of relevance for the phytoremediation of As-contaminated sites. [ABSTRACT FROM AUTHOR]

The chemical extractability of As and Pb (by 5 mM CaCl, 0.1 M HCl, 0.05 M NH (HPO), and aqua regia) from soils and their phytoavailability (by Brassica juncea) were assessed using 16 soil samples collected as a function of distance from mine pits across three long-term abandoned metallic mine sites. The total concentrations of As and Pb (17-41,000 and 27-10,047 mg kg, respectively) decreased with increasing separation distance from the mine pits along a declining slope. However, the percentage of chemically leachable As and Pb mass (e.g., by 5 mM CaCl, 0.1 M HCl, or 0.05 M NH(HPO)) relative to total mass (e.g., by aqua regia) tended to increase exponentially with distance, indicating more chemically labile fractions present in less contaminated downgradient soils. Among soil components, extractable As concentrations were best described by coupling DCB-Al with other Al and Fe oxides. For Pb concentration, pH coupled to DCB-Al or Ox-Al provided a good predictive relationship. The inhibitory growth and uptake by plants were best correlated with the extractable concentrations by 5 mM CaCl and 0.1 M HCl. In conclusion, the chemical extractability and phytoavailability of As and Pb are highly influenced by the relative labile fraction in abandoned mine soils, and its distribution in soils is essentially correlated with sampling distance from mine pits. [ABSTRACT FROM AUTHOR]

[Display omitted] Arsenic (As) has been in the forefront of toxicological research due to its continual worldwide human exposure and its adverse effects including genotoxicity. The study assessed the potential ameliorative effect of Indian mustard seeds (Brassica juncea) and their nanoparticles against arsenic toxicity. Male Wistar rats were used for the exposure study. Group I was control and group V was exposed only to the nanoparticles. Groups II, III, and IV were exposed to 10 mg/kg sodium arsenite for two weeks. Groups III and IV were treated with mustard seeds and the nanoparticles (500 mg/kg) respectively. Arsenic intoxication caused a marked increase in the levels of As in the brain. Additionally, oxidative damage was exhibited with significantly enhanced levels of serum 8-OHdG and hepatic p53 and pS15. The pictographs and the analyzed parameters of the COMET assay illustrated DNA damage with significantly increased values of tail moment and length. Treatment with mustard seeds and its nanoparticles markedly reversed the adverse effects of As toxicity, which is attributed to the presence of a gamut of constituent phytocompounds in the mustard seeds. Taken together the nano formulation was more efficacious and could be introduced as a potential nutraceutical to combat metal toxicity. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of arsenic (As) exposure on carbon, nitrogen, and sulfur (CNS) metabolism in Brassica juncea. Two contrasting, tolerant (TPM-1) and sensitive (TM-4), varieties of B. Juncea were selected and grown either in control sand (150 g) or in sand containing 10 mg of arsenate. Harvesting was performed at 7 and 15 days and various metabolites and enzymes of CNS as well as γ-aminobutyric acid (GABA) metabolism were analyzed. At 7 days, TM-4 showed significantly higher As accumulation and stressed phenotype with increase in superoxide radicals, malondialdehyde, and cell death, as compared with TPM-1. However, the level of hydrogen peroxide was higher in TPM-1 than in TM-4. The level of GABA and the activity of glutamate decarboxylase increased in both roots and shoots of TPM-1, but not in TM-4. The level of nitrate and sulfate increased and decreased in shoots of TPM-1 and TM-4, respectively. The supply of fumarate and succinate was maintained in both shoots and roots of TPM-1 while it was only in shoots of TM-4. There was significant alteration in the profile of amino acids and in sulfur and nitrogen metabolism. However, at 15 days, As accumulation of both varieties was found to be similar along with an increase in GABA, nitrate, and sulfate in both shoots and roots except sulfate in TM-4. Supply of fumarate and succinate was also maintained and other responses were found to be similar in TPM-1 and TM-4. The study demonstrates that responses of CNS metabolism differ in varietal and time-dependent manner. [ABSTRACT FROM AUTHOR]

Arsenic (As) contamination in the environment has attracted considerable attention worldwide. The objective of the present study was to see the comparative effect of As species As(III) and As(V) on accumulation, biochemical responses, and gene expression analysis in Brassica juncea var. Pusa Jaganath (PJn). Hydroponically grown 14-day-old seedlings of B. juncea were treated with different concentrations of As(III) and As(V). Accumulation of total As increased with increasing concentration of both As species and exposure time, mainly in roots. Reduction in seed germination, root-shoot length, chlorophyll, and protein content were observed with increasing concentration and exposure time of both As species, being more in As(III)-treated leaves. PJn variety showed that antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX)) and stress-related parameters (cysteine, proline, and malondialdehyde (MDA)) were stimulated and allows plant to tolerate both As species. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis in leaves showed significant changes in protein profile with more stringent effect with As(III) stress. Semiquantitative RT-PCR analysis showed regulation in expression of phytochelatin synthase ( PCS), metallothionine-2 ( MT-2), glutathione reductase ( GR), and glutathione synthetase ( GS) genes under both As(III) and As(V) stresses. Results suggested that accumulation and inhibition on physiological parameters differ according to the As species, while molecular and biochemical parameters showed a combinatorial type of tolerance mechanism against As(III) and As(V) stresses. [ABSTRACT FROM AUTHOR]

Ten Indian mustard ( Brassica juncea L.) genotypes were screened for their phytoremediation potential for arsenic (As) contaminated water under laboratory-controlled conditions. The genotypes were grown in a hydroponic chamber for 20 days in 250-mL beakers containing As-contaminated water. During plant development, changes in plant growth, biomass, and total As were evaluated. Of the 10 genotypes (Pusa Agrani, BTO, Pusa Kranti, Pusa Bahar, Pusa Bold, Pusa Basant, Pusa Jai Kisan, Arka Vardhan, Varuna, and Vaibhav) Pusa Jai Kisan was the most effective in phytoremediating As-contaminated water under hydroponic conditions. This will provide new information for Indian mustard genotypes for phytoremediating As-contaminated soils. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) constitute a novel mechanism of gene regulation affecting plant development, growth, and stress response. To study the role of miRNAs in arsenic (As) stress, microarray profiling of miRNAs was performed in Brassica juncea using a custom Phalanx Plant OneArray™ containing 381 unique miRNA probes representing 618 miRNAs from 22 plant species. miRNA microarray hybridization of roots exposed to As for 1h and 4h revealed that a total of 69 miRNAs belonging to 18 plant miRNA families had significantly altered expression. The As-responsive miRNAs also exhibited a time- and organ-dependent change in their expression. Putative target prediction for the miRNAs suggested that they regulate various developmental processes (e.g. miR156, miR169, and miR172), sulphur uptake, transport, and assimilation (miR395, miR838, and miR854), and hormonal biosynthesis and/or function (e.g. miR319, miR167, miR164, and miR159). Notable changes were observed in the level of auxins [indole-3-acetic acid (IAA), indole-3- butyric acid, and naphthalene acetic acid], jasmonates [jasmonic acid (JA) and methyl jasmonate], and abscisic acid. The exogenous supply of JA and IAA improved growth of plants under As stress and altered expression of miR167, miR319, and miR854, suggesting interplay of hormones and miRNAs in the regulation of As response. In conclusion, the present work demonstrates the role of miRNAs and associated mechanisms in the plant’s response towards As stress. [ABSTRACT FROM AUTHOR]

The presence of excessive amounts of heavy metals such as arsenic in the environment is a problem in many parts of the world. Many countries e.g., Bangladesh are already severely affected by arsenic contamination of soil and groundwater. Phytoaccumulation is a method in which plants are used to uptake heavy metals from soil. The genus Brassica has many species that can efficiently accumulate arsenic. Despite many studies on phytoaccumulation, little is known about the genetics of phytoaccumulation of Brassica. This study investigated the genetic effect on phytoaccumulation of arsenic in Brassica juncea L. and attempted to identify any morphological trait(s) for phytoaccumulation. Two cultivars of B. juncea namely, B. juncea cv. Rai and B. juncea cv. BARI-11 were chosen as parents for the study. A set of their morphological characteristics were selected to evaluate their potential as marker(s) for phytoaccumulation. A single concentration, 15 ppm of arsenic was used to study the genetic effect on phytoaccumulation using quantitative genetics. The results revealed that phytoaccumulation of arsenic (by the root and shoot systems) is heritable in the broad sense and polygenic in nature. The stem diameter was also found to be heritable in the broad sense and path analysis indicated that it has a significant direct effect on the shoot uptake. It is concluded that phytoaccumulation of arsenic in B. juncea (cvs. Rai and BARI-11) is a genetic phenomenon and stem diameter may be a potential marker of phytoaccumulation of arsenic in B. juncea (cvs. Rai and BARI-11). [ABSTRACT FROM AUTHOR]

Comparative antioxidant profiling of tolerant (TPM-1) and sensitive (TM-4) variety of Brassica juncea L. was performed after exposure to arsenate [As(V)] and arsenite [As(III)]. TPM-1 demonstrated higher accumulation of As upon exposure to both 500 μM As(V) and 250 μM As(III) (49 and 37 μg g−1 dw after 15 days) as compared with that observed in TM-4. The activities of various antioxidant enzymes and the level of glutathione and proline demonstrated, in general, a comparatively better response in TPM-1 than in TM-4 that presumably allowed TPM-1 to tolerate higher As concentrations as compared with that of TM-4. [ABSTRACT FROM AUTHOR]

The mechanisms of perception of arsenic (As)-induced stress and ensuing tolerance in plants remain unresolved. To obtain an insight into these mechanisms, biochemical and transcriptional profiling of two contrasting genotypes of Brassica juncea was performed. After screening 14 varieties for As tolerance, one tolerant (TPM-1) and one sensitive (TM-4) variety were selected and exposed to arsenate [As(V)] and arsenite [As(III)] for 7 d and 15 d for biochemical analyses. The tolerant variety (TPM-1) demonstrated higher accumulation of As upon exposure to both 500 μM As(V) and 250 μM As(III) [49 μg g−1 and 37 μg g−1 dry weight (dw) after 15 d] as well as a better response of thiol metabolism as compared with the responses observed in the sensitive variety (TM-4). Transcriptional profiling of selected genes that are known to be responsive to sulphur depletion and/or metal(loid) stress was conducted in 15-d-old seedlings after 3 h and 6 h exposure to 250 μM As(III). The results showed an up-regulation of sulphate transporters and auxin and jasmonate biosynthesis pathway genes, whereas there was a down-regulation of ethylene biosynthesis and cytokinin-responsive genes in TPM-1 within 6 h of exposure to As(III). This suggested that perception of As-induced stress was presumably mediated through an integrated modulation in hormonal functioning that led to both short- and long-term adaptations to combat the stress. Such a coordinated response of hormones was not seen in the sensitive variety. In conclusion, an early perception of As-induced stress followed by coordinated responses of various pathways was responsible for As tolerance in TPM-1. [ABSTRACT FROM PUBLISHER]

The ability to tolerate and accumulate arsenic (As) and cadmium (Cd) was compared between Brassica juncea (Indian mustard) and Crambe abyssinica (Hochst.) (Crambe or Abyssinian mustard). Plants were grown hydroponically and treated with 70 µM sodium arsenate or 50 µ M cadmium chloride for two weeks. When nutrients were omitted during the As treatment, leaves of C. abyssinica accumulated an average of 140 mg As kg -1 , compared with 34 mg kg -1 for B. juncea . When quarter-strength Hoagland's nutrient solution was provided during As treatment, leaves of C. abyssinica accumulated an average of 270 mg As kg -1 , compared with 13 mg kg -1 for B. juncea . Cadmium accumulation on a dry-weight basis was approximately two times greater in shoots of B. juncea . Shoot biomass production in the presence or absence of metals was greatest for C. abyssinica . Because of its larger biomass and more efficient accumulation of As, C. abyssinica should be considered for use in phytoremediation research. [ABSTRACT FROM AUTHOR]

Biochar application to As-contaminated soil can alter various soil chemical properties, and it can affect available As, plant As uptake, and As phytotoxicity. Increased dissolved organic carbon (DOC) and P released from biochar affect As behavior in the soil system. In this study, we evaluated the effect of biochar application on the chemical properties of soil and phytotoxicity in Brassica juncea using correlation analysis and partial least squares path modeling (PLS-PM). Biochar application increased electrical conductivity (EC), DOC, available P and available As. However, the increased available As did not significantly affect As uptake by B. juncea due to the decrease in the relative ratio and effect of available As with increase in available P derived from biochar. Moreover, biochar application negatively affected soil chemical properties (pH, EC, DOC, available P, and available As) and As uptake by B. juncea. Therefore, correlation analysis and PLS-PM analysis are useful tools to interpret the interactions among influencing factors in the soil-plant system. An approach at the equivalent molecular level rather than concentration should be adopted in future studies. • Biochar application to the soil increases DOC, available P and available As. • Available As is increased but the As uptake by B. juncea does not increase. • Correlation and PLS-PM analysis also demonstrate same trends of results. • Ratio of available As to available P has a decisive effect on As uptake by B. juncea [ABSTRACT FROM AUTHOR]

Phytoremediation makes use of hyperaccumulating plants to remove potentially toxic elements (PTEs) from soil selectively. Most researches examining hyperaccumulators focused on how they act on a single PTE contaminant. However, there is more than one kind of PTEs in most contaminated soils. Phytoremediation approaches could be less effective in environments containing multiple PTEs contaminants. Here we examine arsenic (As) and lead (Pb) accumulation in Indian Mustard (Brassica juncea) from solutions with one or both pollutants. Indian mustard accumulates As or Pb when exposed in the single liquid exposure of As or Pb, and the highest concentrations of As and Pb in Indian Mustard reach 1,786 mg/kg and 47,200 mg/kg, respectively. But the absorption efficiencies of As and Pb decrease (by >90% for As, and ∼10–30% for Pb) when both As and Pb are present. The translocation of As and Pb from the root to leaf is also impeded by 36%–88% for As and 55–85% for Pb when treated with both PTEs. In As and Pb co-treatment, significant negative correlations between As (V) and P and between Pb and other elements (including K, Mg and Ca) were found in Indian mustard. X-ray absorption near edge (XANES) spectroscopy and subcellular extraction experiments indicate that much of the accumulated Pb bound within lead phosphate particles, and often located within the cell wall. Pb could decrease the percentage of water-soluble As and increase protein combined As in subcellular levels within Indian mustard. Based on these data, we suggest that the competition between Pb and monovalent and divalent nutrients (e.g., Ca(II), Mg(II) and K(I)), and the formation of lead phosphates within cell walls play critical roles in decreasing As and Pb co-uptake efficiencies for Indian mustard. Image 1 • Soil pollution is not caused by a single but multiple potentially toxic elements. • Complex As + Pb treatment decreases Indian Mustard uptake of As and Pb by 90% and 30%. • Negative correlations with cations like K Ca and Mg decrease co-uptake of As and Pb. • X ray absorption spectroscopy indicates Pb bounds in the cell wall as Pb phosphates. • Uptake competition and phosphates residues decrease complex As + Pb phytoaccumulation. [ABSTRACT FROM AUTHOR]

Arsenic (As) polluted food chain has become a serious issue for the growth and development of humans, animals and plants. Nitric oxide (NO) or silicon (Si) may mitigate As toxicity. However, the combined application of NO and Si in mitigating As uptake and phytotoxicity in Brassica juncea is unknown. Hence, the collegial effect of sodium nitroprusside (SNP), a NO donor and Si application on B. juncea growth, gas exchange parameters, antioxidant system and As uptake was examined in a greenhouse experiment. Arsenic toxicity injured cell membrane as signposted by the elevated level of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2), thus decreasing the growth of stressed plants. Moreover, As stress negatively affected gas exchange parameters and antioxidative system of plants. However, NO or/and Si alleviated As induced oxidative stress through increasing the activity of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), glutathione S-transferase (GST), glutathione (GSH), along with thiol and proline synthesis. Furthermore, plants treated with co-application of NO and Si showed improved growth, gas attributes and decreased As uptake under As regimes. The current study highlights that NO and Si synergistically interact to mitigate detrimental effects of As stress through reducing As uptake. Our findings recommend combined NO and Si application in As spiked soils for improvement of plant growth and stress alleviation. • As reduced overall growth of Brassica juncea plants. • NO and Si mitigated As stress in B. juncea plants. • Combined application of NO and Si was more effective to reduce As contents and toxicity in plants. [ABSTRACT FROM AUTHOR]