scholarly journals Arbuscular Mycorrhizal Fungi (AMF) as Buffer for Heavy Metals Phytoextraction by Cucurbita maxima Duch. Grown on Crude Oil Contaminated Soil

2018 ◽  
Vol 3 ◽  
pp. 1-12
Author(s):  
Okon G. Okon ◽  
J.E. Okon ◽  
G.D.O. Eneh
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Crude Oil ◽  
Mycorrhizal Fungi ◽  
Growth Parameters ◽  
Chemical Properties ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Heavy Metal Accumulation ◽  
Cucurbita Maxima

This study evaluated the influence of Arbuscular Mycorrhizal (Rhizophagus irregularis) fungi inoculation (M) on the growth ofCucurbita maximaand as a buffer against phytoextraction of selected heavy metals (HM) (Zn, Cu, Cr, Cd and Pb) from a soil contaminated with crude oil (C). The experiment was set up using four soil treatments, each with three replicates C+ M-, C+ M+, C-M+ and C-M- (control without oil and inoculum). The shoot length, petiole length, number of nodes, leaf area and percentage germination ofC. maximawere significantly (p=0.05) reduced in uninoculated crude oil treatment (C+ M-), unpolluted mycorrhizal inoculated treatments (C-M+) showed remarkable response in growth parameters above the control (C-M-), while the polluted and inoculated treatment (C+ M+) showed significant (p=0.05) increase in growth parameters when compared to the polluted uninoculated treatment (C+ M-). Heavy metals analysis revealed a significant (p=0.05) difference in the heavy metal accumulation ofC. maxima. The heavy metals analyzed in this study are present thus inC. maxima; Zn>Cu>Cr>Pb>Cd. Crude oil polluted uninoculated treatment (C+ M-) recorded the highest concentrations of heavy metals than crude oil polluted inoculated (R. irregularis) treatment (C+ M+). Mycorrhizal inoculated unpolluted treatment (C-M+) and unpolluted uninoculated treatment (C-M-) indicated the lowest heavy metal concentrations. Inoculation withR. irregularissignificantly (p=0.05) reduced heavy metals uptake byC. maximaas observed in this study. Also, the negative effect of crude oil on AMF root colonization ofC. maximabyR. irregulariswas observed in polluted and inoculated treatment. HM often accumulate in the top layer of soil, therefore, are available for uptake by plants via roots, which is a major entry point of HM that ultimately affects different physiological processes. AM fungi can impinge on the chemical properties of heavy metals in the soil, their absorption by the host plant, and their allocation to different plant parts, affecting plant growth and the bioremediation process, thus making the AM fungi a suitable buffer for mitigating heavy metal stress onC. maxima.

scholarly journals Arbuscular Mycorrhizal Fungi as Potential Agents in Ameliorating Heavy Metal Stress in Plants

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 815 ◽  
Author(s):  
Rajni Dhalaria ◽  
Dinesh Kumar ◽  
Harsh Kumar ◽  
Eugenie Nepovimova ◽  
Kamil Kuča ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Environmental Pollutants ◽  
Arbuscular Mycorrhizal ◽  
Heavy Metal Stress ◽  
Antioxidant Response ◽  
Heavy Metal Accumulation ◽  
Metal Stress

Heavy metal accumulation in plants is a severe environmental problem, rising at an expeditious rate. Heavy metals such as cadmium, arsenic, mercury and lead are known environmental pollutants that exert noxious effects on the morpho-physiological and biological attributes of a plant. Due to their mobile nature, they have become an extended part of the food chain and affect human health. Arbuscular mycorrhizal fungi ameliorate metal toxicity as they intensify the plant’s ability to tolerate metal stress. Mycorrhizal fungi have vesicles, which are analogous to fungal vacuoles and accumulate massive amount of heavy metals in them. With the help of a pervasive hyphal network, arbuscular mycorrhizal fungi help in the uptake of water and nutrients, thereby abating the use of chemical fertilizers on the plants. They also promote resistance parameters in the plants, secrete a glycoprotein named glomalin that reduces the metal uptake in plants by forming glycoprotein–metal complexes, and improve the quality of the soil. They also assist plants in phytoremediation by increasing the absorptive area, increase the antioxidant response, chelate heavy metals and stimulate genes for protein synthesis that reduce the damage caused by free radicals. The current manuscript focuses on the uptake of heavy metals, accumulation, and arbuscular mycorrhizal impact in ameliorating heavy metal stress in plants.

scholarly journals Scope and future perspectives of phytoremediation

2021 ◽  
Vol 16 (AAEBSSD) ◽  
pp. 77-85
Author(s):  
Sridevi Tallapragada ◽  
Rajesh Lather ◽  
Vandana ◽  
Gurnam Singh
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Genetic Engineering ◽  
Plant Growth ◽  
Mycorrhizal Fungi ◽  
Large Scale ◽  
Negative Impact ◽  
Heavy Metal Accumulation ◽  
Plant Growth Promoting Bacteria ◽  
Runoff Water

Phytoremediation is the plant-based technology that has emerged as a novel cost effective and ecofriendly technology in which green plants are used for extraction, sequestration and/or detoxification of the pollutants. Plants possess the natural ability to degrade heavy metals and this property of plants to detoxify contaminants can be used by genetic engineering approach. Currently, the quality of soil and water has degraded considerably due heavy metal accumulation through discharge of industrial, agricultural and domestic waste. Heavy metal pollution is a global concern and a major health threat worldwide. They are toxic, and can damage living organisms even at low concentrations and tend to accumulate in the food chain. The most common heavy metal contaminants are: As, Cd, Cr, Cu, Hg, Pb and Zn. High levels of metals in soil can be phytotoxic, leading to poor plant growth and soil cover due to metal toxicity and can lead to metal mobilization in runoff water and thus have a negative impact on the whole ecosystem. Phytoremediation is a green strategy that uses hyperaccumulator plants and their rhizospheric micro-organisms to stabilize, transfer or degrade pollutants in soil, water and environment. Mechanisms used to remediate contaminated soil includes phytoextraction, phytostabilization, phytotransformation, phytostimulation, phytovolatilization and rhizofiltration. Traditional phytoremediation method presents some limitations regarding their applications at large scale, so the application of genetic engineering approaches such as transgenic transformation, nanoparticles addition and phytoremediation assisted with phytohormones, plant growth-promoting bacteria and Arbuscular mycorrhizal fungi (AMF) inoculation has been applied to ameliorate the efficacy of plants for heavy metals decontamination. In this review, some recent innovative technologies for improving phytoremediation and heavy metals toxicity and their depollution procedures are highlighted.

scholarly journals Diversity of Arbuscular Mycorrhizal Fungus Populations in Heavy-Metal-Contaminated Soils

1999 ◽  
Vol 65 (2) ◽  
pp. 718-723 ◽  
Author(s):  
C. Del Val ◽  
J. M. Barea ◽  
C. Azcón-Aguilar
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Contaminated Soils ◽  
Agricultural Soils ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Wiener Index ◽  
Life Cycles ◽  
The European Union

ABSTRACT High concentrations of heavy metals have been shown to adversely affect the size, diversity, and activity of microbial populations in soil. The aim of this work was to determine how the diversity of arbuscular mycorrhizal (AM) fungi is affected by the addition of sewage-amended sludge containing heavy metals in a long-term experiment. Due to the reduced number of indigenous AM fungal (AMF) propagules in the experimental soils, several host plants with different life cycles were used to multiply indigenous fungi. Six AMF ecotypes were found in the experimental soils, showing consistent differences with regard to their tolerance to the presence of heavy metals. AMF ecotypes ranged from very sensitive to the presence of metals to relatively tolerant to high rates of heavy metals in soil. Total AMF spore numbers decreased with increasing amounts of heavy metals in the soil. However, species richness and diversity as measured by the Shannon-Wiener index increased in soils receiving intermediate rates of sludge contamination but decreased in soils receiving the highest rate of heavy-metal-contaminated sludge. Relative densities of most AMF species were also significantly influenced by soil treatments. Host plant species exerted a selective influence on AMF population size and diversity. We conclude based on the results of this study that size and diversity of AMF populations were modified in metal-polluted soils, even in those with metal concentrations that were below the upper limits accepted by the European Union for agricultural soils.

scholarly journals Response of Arbuscular Mycorrhizal Fungi to Hydrologic Gradients in the Rhizosphere ofPhragmites australis(Cav.) Trin ex. Steudel Growing in the Sun Island Wetland

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Li Wang ◽  
Jieting Wu ◽  
Fang Ma ◽  
Jixian Yang ◽  
Shiyang Li ◽  
...  
Keyword(s):  
Host Plant ◽  
Mycorrhizal Fungi ◽  
Plant Biomass ◽  
Growth Parameters ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
The Sun ◽  
Vegetative Period ◽  
Hydrologic Gradients ◽  
Mycorrhizal Association

Within the rhizosphere, AM fungi are a sensitive variable to changes of botanic and environmental conditions, and they may interact with the biomass of plant and other microbes. During the vegetative period of thePhragmites australisgrowing in the Sun Island Wetland (SIW), the variations of AM fungi colonization were studied. Root samples of three hydrologic gradients generally showed AM fungi colonization, suggesting that AM fungi have the ability for adaptation to flooded habitats. There were direct and indirect hydrological related effects with respect to AM fungi biomass, which interacted simultaneously in the rhizosphere. Though water content in soil and reed growth parameters were both positively associated with AM fungi colonization, only the positive correlations between reed biomass parameters and the colonization could be expected, or both the host plant biomass and the AM fungi could be beneficial. The variations in response of host plant to the edaphic and hydrologic conditions may influence the effectiveness of the plant-mycorrhizal association. This study included a hydrologic component to better assess the role and distribution of AM fungi in wetland ecosystems. And because of that, the range of AM fungi was extended, since they actually showed a notable adaptability to hydrologic gradients.

scholarly journals Correlations Between Indigenous Mycoparasitic and Symbiotic Beneficial Fungi at Heavy Metal Stress  

2002 ◽  
Vol 51 (1-2) ◽  
pp. 115-122 ◽  
Author(s):  
Zoltán Naár ◽  
F. Román ◽  
A. Füzy
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Mycorrhizal Fungi ◽  
Red Clover ◽  
Arbuscular Mycorrhizal ◽  
Heavy Metal Stress ◽  
Pot Experiment ◽  
Infection Frequency ◽  
Set Up ◽  
Beneficial Fungi

The abundance and diversity of indigenous Trichoderma fungi were tested for correlations with the natural colonization of symbiotic arbuscular mycorrhizal fungi (AMF) in Cd-, Zn- and Ni-polluted soils. Infection frequency (F%) and arbusculum richness (a%) of the mycorrhiza fungi were estimated on red clover grown in a pot experiment set up with calcareous loamy chernozem soil contaminated with Cd, Ni and Zn salts (in 0, 30, 90 and 270 mg kg -1 dry soil concentration) in the field, eight years prior to the pot experiment. Correlation analyses were used to assess the effect of different heavy metal loads on the interrelations of these two types of beneficial fungi. When the test was performed for single variables, significant correlations could be found with very close (r > 0.96 at p < 0.05) results. The rate and direction (positive or negative) of correlations, however, varied with the type of heavy metals. With the combinations of some Trichoderma and mycorrhiza parameters a significant model was obtained for the infection frequency (R² = 0.9405 at p = 0.0062) and for arbusculum richness (R² = 0.997 at p = 0.0007), which suggests a significant complex influence between the symbiotic (AMF) and the free-living ( Trichoderma ) beneficial fungi. This interaction was altered by heavy metals. In the Ni treatments, the correlation data were always negative between the two groups of beneficial fungi.  

scholarly journals Influence of drought and salt stress on the growth of young Populus nigra ‘Italica’ plants and associated mycorrhizal fungi and non-mycorrhizal fungal endophytes

New Forests ◽  
2021 ◽  
Author(s):  
Magdalena Kulczyk-Skrzeszewska ◽  
Barbara Kieliszewska-Rokicka
Keyword(s):  
Salt Stress ◽  
Soil Salinity ◽  
Mycorrhizal Fungi ◽  
Growth Parameters ◽  
Fungal Endophytes ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Populus Nigra ◽  
Stress Factors ◽  
Symbiotic Associations

AbstractPopulus nigra ‘Italica’ (Lombardy poplar) is a breeding cultivar of black poplar, widely used as a street tree or windbreak, often exposed to salinity and limited water availability. Populus roots can develop dual mycorrhizal associations with ectomycorrhizal (ECM) and arbuscular mycorrhizal (AM) fungi, and with non-mycorrhizal fungal endophytes (FE). The symbiotic fungi may alleviate the effects of adverse environmental conditions. We investigated the performance (growth and symbiotic associations) of one-year-old Populus nigra ‘Italica’ grown from woody cuttings in soil from natural poplar habitat and subjected to water scarcity and soil salinity (50 mM NaCl, 150 mM NaCl, 250 mM NaCl). With increasing soil salinity, a decrease in the growth parameters of the aboveground parts of the poplar plantlets and their fine roots were found; however, the roots were more resistant to the stress factors analyzed than the shoots. ECMF, AMF, and non-mycorrhizal FE were all tolerant to increased salt levels in the soil, and the ECM abundance was significantly higher under conditions of mild salinity (50 mM NaCl, 150 mM NaCl) compared to the control plants and those treated with 250 mM NaCl. Our results indicated that enhanced soil salinity increased the content of sodium and chlorine in leaves, but did not affect significantly the concentrations potassium, magnesium, calcium, phosphorus, or nitrogen. Significant accumulation of proline in leaves suggest salt stress of P. nigra ‘Italica’ treated with 250 mM NaCl and contribution of proline to the plant defense reactions.

scholarly journals Effects of Arbuscular Mycorrhizal Fungi on Accumulation of Heavy Metals in Rhizosphere Soil

2018 ◽  
Vol 3 (1) ◽  
pp. 31
Author(s):  
Jiayong HE ◽  
Weijie XU
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Arbuscular Mycorrhizal Fungi ◽  
Mycorrhizal Fungi ◽  
Host Plants ◽  
Rhizosphere Soil ◽  
Preliminary Investigation ◽  
Arbuscular Mycorrhizal ◽  
Cadmium Content ◽  
Soil Changes

<p><em>The rhizosphere soil arbuscular mycorrhizal fungi will affect the absorption of heavy metal substances by the host plants. The effects of the arbuscular mycorrhizal fungi are inhibitory and conversion effects. The type and quantity of AMF fungi are different, and there are also differences in the absorption of arbuscular mycorrhizal fungi in the rhizosphere soil. Changes in the accumulation of heavy metals will affect the growth of arbuscular mycorrhizal fungi in the rhizosphere soil. In this paper, a preliminary investigation is made as to whether the AMF fungus number will affect the absorption of heavy metal Cd. Experiments show that with the increase of soil spores, the available cadmium content of soil also tends to increase.</em></p>

scholarly journals Heavy-Metal Stress and Developmental Patterns of Arbuscular Mycorrhizal Fungi

2004 ◽  
Vol 70 (11) ◽  
pp. 6643-6649 ◽  
Author(s):  
Teresa E. Pawlowska ◽  
Iris Charvat
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Spore Germination ◽  
Arbuscular Mycorrhizal ◽  
Am Fungi ◽  
Metal Stress ◽  
Soil Conditions ◽  
Global Changes ◽  
Extraradical Mycelium ◽  
Metal Concentrations

ABSTRACT The rate of global deposition of Cd, Pb, and Zn has decreased over the past few decades, but heavy metals already in the soil may be mobilized by local and global changes in soil conditions and exert toxic effects on soil microorganisms. We examined in vitro effects of Cd, Pb, and Zn on critical life stages in metal-sensitive ecotypes of arbuscular mycorrhizal (AM) fungi, including spore germination, presymbiotic hyphal extension, presymbiotic sporulation, symbiotic extraradical mycelium expansion, and symbiotic sporulation. Despite long-term culturing under the same low-metal conditions, two species, Glomus etunicatum and Glomus intraradices, had different levels of sensitivity to metal stress. G. etunicatum was more sensitive to all three metals than was G. intraradices. A unique response of increased presymbiotic hyphal extension occurred in G. intraradices exposed to Cd and Pb. Presymbiotic hyphae of G. intraradices formed presymbiotic spores, whose initiation was more affected by heavy metals than was presymbiotic hyphal extension. In G. intraradices grown in compartmentalized habitats with only a portion of the extraradical mycelium exposed to metal stress, inhibitory effects of elevated metal concentrations on symbiotic mycelial expansion and symbiotic sporulation were limited to the metal-enriched compartment. Symbiotic sporulation was more sensitive to metal exposure than symbiotic mycelium expansion. Patterns exhibited by G. intraradices spore germination, presymbiotic hyphal extension, symbiotic extraradical mycelium expansion, and sporulation under elevated metal concentrations suggest that AM fungi may be able to survive in heavy metal-contaminated environments by using a metal avoidance strategy.

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