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•Combined toxicity of Pb, Cd and As remained a dose-response effect.•Co-exposure led to a lower Cd but a higher Pb and As uptake in plant.•NaCl-soluble form was predominant for Pb, Cd ...and As in Solanum nigrum L.•Most Pb, Cd and As were localized in the cell wall and soluble fraction for plant.•The exchangeable Cd and residual Pb/As were the predominant forms in soil.
A 3-factor-5-level central composite design was conducted to investigate the combined toxicity and detoxification mechanisms of lead (Pb), cadmium (Cd) and arsenic (As) in Solanum nigrum L. The three metal(loid)s exhibited low-dose stimulation and high-dose inhibition on plant length. Analyses of eleven oxidative stress and antioxidant parameters showed all Pb, Cd and As induced oxidative damages, and the co-exposure further enhanced their toxic effects. Pb, Cd and As were mainly accumulated in plant roots and poorly translocated to shoots, being beneficial for metal(loid) detoxification. The results of subcellular fractionation showed that Pb, Cd and As in plant leaves, stems and roots were mainly localized in the cell wall and soluble fractions. Most of Pb and As in soils occurred in residual fraction while Cd in exchangeable fraction. Although single Pb, Cd and As in all plant tissues existed predominantly in 1 M NaCl-soluble form, the d-H2O and 80 % ethanol-soluble forms were increased under the binary or ternary combinations. This study will conduce to the potential use of S. nigrum L. in the phytostablization of soil co-contaminated with Pb, Cd and As.
The effects of cadmium (Cd) on the accumulation of hydrogen peroxide (H
2O
2) and antioxidant enzyme activities in roots of
Solanum nigrum L. and the role of
N-acetyl-
l-cysteine (NAC) as a cysteine ...(Cys) donor against Cd toxicity were investigated. Cd at 50 and 200
μM significantly increased the contents of thiobarbituric acid-reactive substances (TBARS), the production of H
2O
2 and superoxide anion (O
2
−), and the activities of catalase, guaiacol peroxidase, ascorbate peroxidase, glutathione peroxidase (GSH-Px), glutathione reductase, and superoxide dismutase. Experiments with diphenylene iodonium as an inhibitor of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and NaN
3 as an inhibitor of peroxidase showed that the major source of Cd-induced reactive oxygen species in the roots may include plasma membrane-bound NADPH oxidase and peroxidase. In addition, the effects of NAC on plant growth, antioxidant enzyme activity, and non-protein thiol content were analyzed. Under Cd stress, the addition of 500
μM NAC decreased the contents of TBARS and production of H
2O
2 and O
2
−, but increased levels of Cys and reduced glutathione (GSH), phytochelatins, and activity of GSH-Px in roots. These results suggest that NAC could protect plants from oxidative stress damage, and this protection seems to be performed via increased GSH biosynthesis. Furthermore, NAC treatment also increased the contents of protein thiols in
S. nigrum roots. By using size-exclusion chromatography, we found involvement of NAC in the Cd tolerance mechanism through increased biosynthesis of Cd-binding proteins.
To study the effects of indole-3-acetic acid (IAA) on cadmium (Cd) accumulation and the physiological responses of the Cd hyperaccumulator Solanum nigrum and non-hyperaccumulator Solanum melongena, a ...pot experiment was conducted in soil containing 2 mg kg−1 Cd in which different concentrations of IAA (0, 10, 20, or 40 mg L−1) were sprayed on plant leaves. The results showed that Cd accumulation in shoots of S. nigrum was significantly increased by 30% after the addition of 10 mg L−1 IAA under 2 mg kg−1 Cd stress compared to that in the control, but shoot Cd accumulation showed no significant change in S. melongena after this IAA treatment. Additionally, the growth and the proline content in the two species were significantly increased by 20 mg L−1 IAA. The activities of peroxidase and catalase in leaves of S. nigrum and the activity of superoxide dismutase (SOD) in S. melongena were significantly increased and their malondialdehyde content was significantly decreased compared to those in the control. The root activity of S. nigrum was significantly improved after 10 and 20 mg L−1 IAA treatments, but no significant difference was observed in S. melongena. The correlation analysis results showed that the Cd concentration in leaves of S. nigrum was significantly and positively correlated with the carotenoid and proline contents, and there was also a significant positive correlation between the Cd concentration and SOD activity in leaves of S. melongena. Therefore, S. nigrum is an ideal plant for the phytoextraction of Cd-contaminated soil assisted by IAA. IAA promotes Cd accumulation in plant shoots by enhancing the accumulation of carotenoids and proline in S. nigrum and maintaining a high leaf SOD activity in S. melongena.
•Cadmium concentration in shoots of two plants was significantly increased by 20 mg L−1 IAA.•IAA promoted leaf Cd accumulation in two plants by different physiological mechanisms.•Carotenoid and proline were significantly and positively correlated with leaf Cd in S. nigrum.•SOD activity was significantly and positively correlated with leaf Cd in S. melongena.
The growth of hyperaccumulator plants is often compromised by increased toxicity of metals like cadmium (Cd). However, extraction of such metals from the soil can be enhanced by endophytic microbial ...association. Present study was aimed to elucidate the potential of microbe-assisted Cd phytoextraction in hyperaccumulator
Solanum nigrum
plants and their interactions under varied Cd concentrations. An endophytic bacteria
Serratia
sp. RSC-14 was isolated from the roots of
S. nigrum
. In addition to Cd tolerance up to 4 mM, the RSC-14 exhibited phosphate solubilization and secreted plant growth-promoting phytohormones such as indole-3-acetic acid (54 μg/mL).
S. nigrum
plants were inoculated with RSC-14 and were grown in different concentrations of Cd (0, 10, and 30 mg Cd kg
−1
sand). Results revealed that Cd treatment caused significant cessation in plant growth, biomass, and chlorophyll content, whereas significantly higher malondialdehyde (MDA) and electrolyte production in leaves were observed in a dose-dependent manner. Conversely, RSC-14 inoculation relived the toxic effects of Cd-induced stress by significantly increasing root/shoot growth, biomass production, and chlorophyll content and decreasing MDA and electrolytes contents. Ameliorative effects on host growth were also observed by the regulation of metal-induced oxidative stress enzymes such as catalase, peroxidase, and polyphenol peroxidase. Activities of these enzymes were significantly reduced in RSC-14 inoculated plants as compared to control plants under Cd treatments. The lower activities of stress responsive enzymes suggest modulation of Cd stress by RSC-14. The current findings support the beneficial uses of
Serratia
sp. RSC-14 in improving the phytoextraction abilities of
S. nigrum
plants in Cd contamination.
Remediation of heavy metal contaminated sites using hyperaccumulators presents a promising alternative to current environmental methodologies. In the pot-culture experiment, the effects of Cd, and ...Cd–As on the growth and its accumulation in the Cd-hyperaccumulator (
Solanum nigrum L.) were determined. No reduction in plant height and shoot dry biomass was noted when the plants were grown at Cd concentration of ⩽25
mg/kg. The contents of Cd in the stems increased from 122 to 387
mg/kg with increasing Cd, with the Cd transfer factor and bioaccumulation factor being >1.0. The plant can be classified as a Cd-hyperaccumulator. Growing in the presence of 10
mg/kg Cd and 50
mg/kg As, the plant height and shoot dry matter yields did not decrease significantly (
p
>
0.05) compared to that at 10
mg/kg Cd, however the stem Cd content increased by 28%. It was also observed that
S. nigrum used exclusion strategy to reduce As uptake in the roots and restricted translocation into the shoots, resulting in As contents of the plant being root
>
leaf
>
stem
>
seed. The Cd accumulation capacity coupled with its relatively high As tolerance ability could make it useful for phytoremediation of sites co-contaminated by Cd and As.
Alkaloids are common secondary metabolites found also in plants of the large family of Solanaceae, and they contribute frequently to the economic importance of these plants as food, spices, drugs, or ...pharmaceuticals. Matrix-assisted laser desorption/ionization mass spectrometry imaging was applied to visualize the spatial localization of the main steroidal alkaloids in diverse plant tissues of Lycopersicon esculentum, Solanum nigrum, and Solanum dulcamara. Among others, the basic aglycons, tomatidenol, tomatidine, solasodine, and soladulcine, along with their corresponding glycoalkaloids, were identified with distinct distributions within plant tissue structures and plant parts and with respect to the degree of ripeness. The alkaloids are identified by their mass and fragmentation pattern. Multivariate unsupervised principal compound analysis and the k-means clustering analysis were calculated on the basis of all peaks, automatically picked from all selected regions, with total ion count normalization resulting in characterization of the tissues and organs with respect to their chemical similarity. It can therefore be concluded that the tissue-specific localizations of alkaloids in nightshades depend upon the ripeness status and the developmental stage of the plants.
Field trials contribute practical information towards the development of phytoremediation strategies that cannot be provided by laboratory tests. We conducted field experiments utilizing the Cd ...hyperaccumulator plant
Solanum nigrum L., on farmland contaminated with 1.91 mg kg
−1 Cd in the soil. Our study showed that
S. nigrum has a relatively high biomass. Planting density had a significant effect on the plant biomass and thus on overall Cd accumulation. For double harvesting, an optimal cutting position influenced the amount of Cd extracted from soils. Double cropping was found to significantly increase the amount of Cd extracted by
S. nigrum. Fertilizing had no significant effect on plant biomass or on the Cd remediation of the soil over the short-term period. Our study indicates that
S. nigrum can accumulate Cd from soils where the concentrations are relatively low, and thus has application for use in decontamination of slightly to moderately Cd-contaminated soil.
►
S. nigrum L. is an effective phytoremediation plant for Cd-polluted soils. ►Agronomy practices that increase harvested biomass improve bioremediation efficiency. ►Double cropping of
S. nigrum L. is an effective phytoremediation strategy. ►Field experiments are necessary to effectively assess phytoremediation techniques.
Agronomic practice for the phytoremediation potential of
Solanum nigrum L. for Cd uptake was demonstrated in field contaminated soils.
Using accumulators for intercropping in agricultural production can change the heavy metal concentration in the target plants. This study aims to investigate how intercropping wheat (Triticum ...aestivum L.) and Solanum nigrum L. affects soil bacterial community and cadmium (Cd) absorption in response to Cd-contaminated soil. We compared the concentrations and accumulations of Cd by plants, the activities of soil enzymes and the bacterial community structures of rhizosphere soil in monoculture and intercropping system. Principal component analysis (PCA) ordinations showed that soil bacterial communities were significantly separated by MW and IW, which illustrated intercropping with Solanum nigrum L. impacted the bacterial community structure of wheat. Firstly, the results showed that the biomass of shoots and roots in intercropped wheat (IW) were significantly decreased by 16.19% and 29.38% compared with monoculture wheat (MW) after 60 days after transplanting (DAT). Secondly, the Cd concentration and accumulation of shoots in IW was higher than MW. The Cd accumulation of IW shoots and roots were increased 12.87% and 0.98%, respectively after 60 days DAT. Besides, the enzymes activity catalase (CAT), urease (UA) and alkaline phosphatase (ALP) of IW were decreased 35%, 6% and 21%, respectively after 60 days DAT. Finally, the diversity indexes Abundance-based Coverage Estimator (ACE), Chao and InvSimpson of IW were lower than MW. These results indicated that intercropping with Solanum nigrum L. inhibited the wheat growth and decreased the bacterial community diversity in wheat rhizosphere, increased the Cd concentration and accumulation in plant tissues of wheat. Therefore, intercropping Solanum nigrum L. and wheat with Cd-contaminated soil might increase the risk of excessive Cd in wheat.
•Intercropping with hyperaccumulator had an impact on Cd accumulation of cash crop.•Cd accumulation, bacterial community and various enzymes activity were conducted.•The bacterial community of wheat was strongly affected by planting patterns.•Intercropping increased the risk of excessive Cd in wheat on Cd-contaminated soil.
Solanum nigrum is a cadmium (Cd) accumulator, whereas Solanum torvum is a low Cd-accumulating plant. The molecular mechanisms that are responsible for differential cadmium (Cd) accumulation in the ...two Solanum species are poorly understood.
Here, grafting experiments confirmed that increased Cd loading into the root xylem was responsible for the differential Cd accumulation in the two Solanum species. An iron (Fe) supply assay indicated that low Fe accumulation in S. torvum leaves is related to its Cd sensitivity.
Transcriptome analyses revealed higher expression of the genes that encode several metal transporters as well as antioxidant-related genes, and several organic and amino acid biosynthesis/metabolism-related genes in Cd-treated S. nigrum. Our data also indicated that the different responsive mechanisms of the transporter genes to Fe deficiency might be responsible for differential uptake and redistribution of metals in the two Solanum species
These results form a basis upon which to further explore the molecular mechanisms of Cd accumulation and tolerance, and provide an insight into novel strategies that can be used for phytoremediation and food safety.
The effects of
Bacillus
sp. SLS18, a plant-growth-promoting endophyte, on the biomass production and Mn/Cd uptake of sweet sorghum (
Sorghum bicolor
L.),
Phytolacca acinosa
Roxb., and
Solanum nigrum
...L. were investigated. SLS18 displayed multiple heavy metals and antibiotics resistances. The strain also exhibited the capacity of producing indole-3-acetic acid, siderophores, and 1-aminocyclopropane-1-carboxylic acid deaminase. In pot experiments, SLS18 could not only infect plants effectively but also significantly increase the biomass of the three tested plants in the presence of Mn/Cd. The promoting effect order of SLS18 on the biomass of the tested plants was sweet sorghum >
P. acinosa
>
S. nigrum
L. In the presence of Mn (2,000 mg kg
−1
) and Cd (50 mg kg
−1
) in vermiculite, the total Mn/Cd uptakes in the aerial parts of sweet sorghum,
P. acinosa
, and
S. nigrum
L. were increased by 65.2%/40.0%, 55.2%/31.1%, and 18.6%/25.6%, respectively, compared to the uninoculated controls. This demonstrates that the symbiont of SLS18 and sweet sorghum has the potential of improving sweet sorghum biomass production and its total metal uptake on heavy metal-polluted marginal land. It offers the potential that heavy metal-polluted marginal land could be utilized in planting sweet sorghum as biofuel feedstock for ethanol production, which not only gives a promising phytoremediation strategy but also eases the competition for limited fertile farmland between energy crops and food crops.
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