Diversity and heavy metal tolerance of endophytic fungi from six dominant plant species in a Pb–Zn mine wasteland in China

Phytoremediation has been suggested as a solution to heavy metal—polluted soils, but the choices of suitable plant species for phytoremediation have been limited. Medicinal and aromatic plants appear to be excellent selections for these plantings, since these plants are grown for economically valuable secondary products (essential oils), not for food or feed. Preliminary research indicates that heavy metals are not accumulated in essential oils, permitting the oil to be used commercially. Productivity of some, but not all aromatic plants was reduced, however, by the heavy metals. The objective of our experiment was to distinguish the mechanism of heavy metal tolerance of plants using germinating seeds of medicinal and aromatic plant species. Seeds from medicinal and aromatic plants were germinated in solutions with selected levels of heavy metals (cadmium at 6 and 10 (μg·L-1; copper at 60 and 150 μg·L-1; lead at 100 and 500 μg·L-1; zinc at 400 and 800 μg·L-1) and in distilled water. Tests on Anethum graveolens L., Carum carvi L., Cuminum cyminum L., Foeniculum vulgare Mill., Pimpinella anisum L., Ocimum basilicum L., and the hyperaccumulator species Brassica juncea L. and Alyssum bertolonii established that different plant species reacted in different ways to the heavy metals. For example, cadmium did not decrease seed germination of Alyssum, O. basilicum, and B. juncea compared with germination in water but did decrease germination of C. cyminum. Lead did not affect germination of A. bertolonii and B. juncea as compared with water but did negatively affect germination of P. anisum, F. vulgare, and C. cyminum. Except for B. juncea, F. vulgare, and C. cyminum, copper had a negative effect on germination. Zinc decreased germination in all tested species except B. juncea.

Download Full-text

Assessment of heavy metal tolerance in two plant species growing in experimental disturbed polluted urban soil

Journal of Soils and Sediments ◽

10.1007/s11368-017-1666-8 ◽

2017 ◽

Vol 18 (6) ◽

pp. 2305-2317 ◽

Cited By ~ 15

Author(s):

Javier Rodríguez-Bocanegra ◽

Núria Roca ◽

Anna Febrero ◽

Jordi Bort

Keyword(s):

Heavy Metal ◽

Plant Species ◽

Urban Soil ◽

Metal Tolerance ◽

Heavy Metal Tolerance

Download Full-text

ISOLATION OF ENDOPHYTIC FUNGI FROM TRIDAX PROCUMBENS GROWN IN CONTAMINATED SITES AND ASSESSMENT OF THEIR HEAVY METAL TOLERANCE

Indian Journal of Applied Microbiology ◽

10.46798/ijam.2021.v23i01.001 ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

Arul Selvi C ◽

Soundhari C

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Endophytic Fungi ◽

Metal Tolerance ◽

Agar Medium ◽

Heavy Metal Tolerance ◽

Contaminated Sites ◽

Potato Dextrose Agar Medium ◽

Fungal Isolates ◽

Tridax Procumbens

Seven strains of endophytic fungi were isolated from the leaves of Tridax procumbens and were first screened individually for tolerance to heavy metals like Zn, Pb, Cu, Mg, and Cr from 5 ppm to 50 ppm on Potato dextrose agar medium. They were further tested for resistance at 75, 100, 200, 400, and 600 ppm of heavy metals. The fungal isolate on the PDA medium without any heavy metal was used as a control for growth comparison. It was observed that with increasing concentration of heavy metal from 5 to 600 ppm there was a decrease in the number of fungal isolates. Few of the fungal isolates were able to tolerate heavy metals up to 600 ppm. The screening test revealed heterogeneity in the heavy metal tolerance of the isolates.

Download Full-text

High Redox Status as the Basis for Heavy Metal Tolerance of Sesuvium portulacastrum L. Inhabiting Contaminated Soil in Jeddah, Saudi Arabia

Antioxidants ◽

10.3390/antiox11010019 ◽

2021 ◽

Vol 11 (1) ◽

pp. 19

Author(s):

Emad A. Alsherif ◽

Turki M. Al-Shaikh ◽

Omar Almaghrabi ◽

Hamada AbdElgawad

Keyword(s):

Heavy Metal ◽

Plant Species ◽

Heavy Metal Contamination ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Field Research ◽

Redox Status ◽

Land Resource ◽

Sesuvium Portulacastrum ◽

Resistant Species

Because sewage sludge is contaminated with heavy metals, its disposal in the soil may pose risks to the ecosystem. Thus, heavy metal remediation is necessary to reduce the associated risks. The goal of this research is to introduce a heavy metal resistant species and to assess its phytoremediation, oxidative damage markers and stress tolerance mechanisms. To this end, field research was done to compare the vegetation of polluted sites to that of a healthy site. We found 42 plant species identified in the study, Sesuvium portulacastrum L. was chosen because of its high relative density (10.3) and maximum frequency (100 percent) in the most contaminated areas. In particular, S. portulacastrum plants were characterized by strong Cu, Ni, and As uptake. At the organ level, to control growth reduction and oxidase damage, particularly in roots, increased detoxification (e.g., metallothionein, phytochelatins) and antioxidants mechanisms (e.g., tocopherols, glutathione, peroxidases). On the other hand, flavonoids content and the activity of glutathione-S transferase, glutathione reductase and dehydroascorbate reductase were increased manly in the shoots. These biochemical markers can be applied to select tolerance plant species grown under complex heavy metal contamination. Our findings also introduced S. portulacastrum to reduce soil contamination0associated risks, making the land resource available for agricultural production.

Download Full-text

Heavy Metal Tolerance Trend in Extended-Spectrum β-Lactamase Encoding Strains Recovered from Food Samples

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18094718 ◽

2021 ◽

Vol 18 (9) ◽

pp. 4718

Author(s):

Kashaf Junaid ◽

Hasan Ejaz ◽

Iram Asim ◽

Sonia Younas ◽

Humaira Yasmeen ◽

...

Keyword(s):

Heavy Metal ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Heavy Metal Resistance ◽

Metal Resistance ◽

Food Samples ◽

Esbl Production ◽

Extended Spectrum ◽

Retail Food ◽

Esbl Producers

This study evaluates bacteriological profiles in ready-to-eat (RTE) foods and assesses antibiotic resistance, extended-spectrum β-lactamase (ESBL) production by gram-negative bacteria, and heavy metal tolerance. In total, 436 retail food samples were collected and cultured. The isolates were screened for ESBL production and molecular detection of ESBL-encoding genes. Furthermore, all isolates were evaluated for heavy metal tolerance. From 352 culture-positive samples, 406 g-negative bacteria were identified. Raw food samples were more often contaminated than refined food (84.71% vs. 76.32%). The predominant isolates were Klebsiella pneumoniae (n = 76), Enterobacter cloacae (n = 58), and Escherichia coli (n = 56). Overall, the percentage of ESBL producers was higher in raw food samples, although higher occurrences of ESBL-producing E. coli (p = 0.01) and Pseudomonas aeruginosa (p = 0.02) were observed in processed food samples. However, the prevalence of ESBL-producing Citrobacter freundii in raw food samples was high (p = 0.03). Among the isolates, 55% were blaCTX-M, 26% were blaSHV, and 19% were blaTEM. Notably, heavy metal resistance was highly prevalent in ESBL producers. These findings demonstrate that retail food samples are exposed to contaminants including antibiotics and heavy metals, endangering consumers.

Download Full-text

Evaluation of bacterial strains isolated from Late Quaternary alluvial sediments spanning ~ 28 m in depth for heavy metal tolerance and Cr(VI) removal ability

International Microbiology ◽

10.1007/s10123-021-00174-0 ◽

2021 ◽

Author(s):

Abhi P. Shah ◽

G. Archana

Keyword(s):

Heavy Metal ◽

Metal Tolerance ◽

Late Quaternary ◽

Heavy Metal Tolerance ◽

Bacterial Strains ◽

Alluvial Sediments

Download Full-text

Effect of Lead and Copper on Photosynthetic Apparatus in Citrus (Citrus aurantium L.) Plants. The Role of Antioxidants in Oxidative Damage as a Response to Heavy Metal Stress

Plants ◽

10.3390/plants10010155 ◽

2021 ◽

Vol 10 (1) ◽

pp. 155

Author(s):

Anastasia Giannakoula ◽

Ioannis Therios ◽

Christos Chatzissavvidis

Keyword(s):

Oxidative Stress ◽

Lipid Peroxidation ◽

Heavy Metal ◽

Metal Tolerance ◽

Heavy Metal Tolerance ◽

Membrane Integrity ◽

Photosynthetic Apparatus ◽

Heavy Metal Stress ◽

Photosynthetic Parameters ◽

Citrus Aurantium

Photosynthetic changes and antioxidant activity to oxidative stress were evaluated in sour orange (Citrus aurantium L.) leaves subjected to lead (Pb), copper (Cu) and also Pb + Cu toxicity treatments, in order to elucidate the mechanisms involved in heavy metal tolerance. The simultaneous effect of Pb− and Cu on growth, concentration of malondialdehyde (MDA), hydrogen peroxide (H2O2), chlorophylls, flavonoids, carotenoids, phenolics, chlorophyll fluorescence and photosynthetic parameters were examined in leaves of Citrus aurantium L. plants. Exogenous application of Pb and Cu resulted in an increase in leaf H2O2 and lipid peroxidation (MDA). Toxicity symptoms of both Pb and Cu treated plants were stunted growth and decreased pigments concentration. Furthermore, photosynthetic activity of treated plants exhibited a significant decline. The inhibition of growth in Pb and Cu-treated plants was accompanied by oxidative stress, as indicated by the enhanced lipid peroxidation and the high H2O2 concentration. Furthermore, antioxidants in citrus plants after exposure to high Pb and Cu concentrations were significantly increased compared to control and low Pb and Cu treatments. In conclusion, this study indicates that Pb and Cu promote lipid peroxidation, disrupt membrane integrity, reduces growth and photosynthesis and inhibit mineral nutrition. Considering the potential for adverse human health effects associated with high concentrations of Pb and Cu contained in edible parts of citrus plants the study signals that it is important to conduct further research into the accessibility and uptake of the tested heavy metals in the soil and whether they pose risks to humans.

Download Full-text