Cadmium Toxicity In Plants Research Articles

The role of exogenous hydrogen sulfide in mitigating cadmium toxicity in plants: A comprehensive meta-analysis.

Reducing the accumulation of cadmium (Cd) and mitigating its toxicity are pivotal strategies for addressing Cd pollution's threats to agriculture and human health. Hydrogen sulfide (H2S) serves as a signaling molecule, playing a crucial role in plant stress defense mechanisms. Nevertheless, a comprehensive assessment of the impact of exogenous H2S on plant growth, antioxidant properties, and gene expression under Cd stress remains lacking. In this meta-analysis, we synthesized 575 observations from 27 articles, revealing that exogenous H2S significantly alleviates Cd-induced growth inhibition in plants. Specifically, it enhances root length (by 8.71%), plant height (by 15.67%), fresh weight (by 15.15%), dry weight (by 22.54%), and chlorophyll content (by 27.99%) under Cd stress conditions. H2S boosts antioxidant enzyme activity, particularly catalase (CAT), by 39.51%, thereby reducing Cd-induced reactive oxygen species (ROS) accumulation. Moreover, it impedes Cd translocation from roots to shoots, resulting in a substantial 40.19% reduction in stem Cd content. Additionally, H2S influences gene expression in pathways associated with antioxidant enzymes, metal transport, heavy metal tolerance, H2S biosynthesis, and energy metabolism. However, the efficacy of exogenous H2S in alleviating Cd toxicity varies depending on factors such as plant species, concentration of the H2S donor sodium hydrosulfide (NaHS), application method, and cultivation techniques. Notably, NaHS concentrations exceeding 200 μM may adversely affect plants. Overall, our study underscores the role of exogenous H2S in mitigating Cd toxicity and elucidates its mechanism, providing insights for utilizing H2S to combat Cd pollution in agriculture.

Se Ameliorates Cd Toxicity in Oilseed rape (Brassica napus L.) Seedlings by Inhibiting Cd Transporter Genes and Maintaining root Plasma Membrane Integrity.

Se (Selenium) has been reported to be an important protective agent to decreases Cd (Cadmium) induced toxic in plants. However, it remains unclear how Se mitigates the uptake of Cd and increased the resistance to Cd toxicity. Hydroponic experiments were arranged to investigate the changes of physiological properties, root cell membrane integrity and Cd-related transporter genes in rape seedlings. Comparison of the biomass between the addition of Se and the absence of Se under Cd exposure showed that the Cd-induced growth inhibition of rape seedlings was alleviated by Se. Cd decreased the photosynthetic rate (Pn), stomatal conductance (Gs) and photosynthetic pigment content including chlorophyll a, chlorophyll b and carotenoid. However, all these parameters were all significantly improved by Se addition. Moreover, exposure to Se resulted in a decrease in Cd concentration in both shoot and root, ranging from 4.28 to 27.2%. Notably, the application of Se at a concentration of 1 µmol L- 1 exhibited the best performance. Furthermore, Se enhanced cell membrane integrity and reduced superoxide anion levels, thereby contributing to the alleviation of cadmium toxicity in plants. More critically, Se decreased the expression levels of root Cd-related transporter genes BnIRT1, BnHMA2 and BnHMA4 under Cd stress, which are responsible for Cd transport and translocation. These results are important to increase crop growth and reduce Cd load in the food chain from metal toxicity management and agronomical point of view.

Effects of α-Fe2O3 nanoparticles and biochar on plant growth and fruit quality of muskmelon under cadmium stress.

Cadmium pollution in farmland has become a global environmental problem, threatening ecological security and human health. Biochar is effective in remediation of soil pollution. However, high concentrations of biochar can inhibit plant growth, and low concentrations of biochar have limited mitigation effect on cadmium toxicity. Therefore, the combination of low-concentration biochar and other amendments is a promising approach to alleviate cadmium toxicity in plants and improve the safety of edible parts. In this study, muskmelon was selected as the research object, and different concentrations of α-Fe2O3 nanoparticles were used alone or combined with biochar to explore the effects of different treatments on muskmelon plants in cadmium-contaminated soil. The results showed that the combined application of 250mg/kg α-Fe2O3 nanoparticles and biochar had a good effect on the repair of cadmium toxicity in muskmelon plants. Compared with cadmium treatment, its application increased plant height by 32.53%, cadmium transport factor from root to stem decreased by 32.95%, chlorophyll content of muskmelon plants increased by 14.27%, and cadmium content in muskmelon flesh decreased by 18.83%. Moreover, after plant harvest, soil available cadmium content in 250mg/kg α-Fe2O3 nanoparticles and biochar combined treatment decreased by 31.18% compared with cadmium treatment. The results of this study provide an effective reference for the composite application of different exogenous amendments and a feasible idea for soil heavy metal remediation and mitigation of cadmium pollution in farmland.

The mechanism of silicon on alleviating cadmium toxicity in plants: A review.

Cadmium is one of the most toxic heavy metal elements that seriously threaten food safety and agricultural production worldwide. Because of its high solubility, cadmium can easily enter plants, inhibiting plant growth and reducing crop yield. Therefore, finding a way to alleviate the inhibitory effects of cadmium on plant growth is critical. Silicon, the second most abundant element in the Earth's crust, has been widely reported to promote plant growth and alleviate cadmium toxicity. This review summarizes the recent progress made to elucidate how silicon mitigates cadmium toxicity in plants. We describe the role of silicon in reducing cadmium uptake and transport, improving plant mineral nutrient supply, regulating antioxidant systems and optimizing plant architecture. We also summarize in detail the regulation of plant water balance by silicon, and the role of this phenomenon in enhancing plant resistance to cadmium toxicity. An in-depth analysis of literature has been conducted to identify the current problems related to cadmium toxicity and to propose future research directions.

Abscisic-Acid-Regulated Responses to Alleviate Cadmium Toxicity in Plants.

High levels of cadmium (Cd) in soil can cause crop yield reduction or death. Cadmium accumulation in crops affects human and animal health as it passes through the food chain. Therefore, a strategy is needed to enhance the tolerance of crops to this heavy metal or reduce its accumulation in crops. Abscisic acid (ABA) plays an active role in plants' response to abiotic stress. The application of exogenous ABA can reduce Cd accumulation in shoots of some plants and enhance the tolerance of plants to Cd; therefore, ABA may have good application prospects. In this paper, we reviewed the synthesis and decomposition of ABA, ABA-mediated signal transduction, and ABA-mediated regulation of Cd-responsive genes in plants. We also introduced physiological mechanism underlying Cd tolerance because of ABA. Specifically, ABA affects metal ion uptake and transport by influencing transpiration and antioxidant systems, as well as by affecting the expression of metal transporter and metal chelator protein genes. This study may provide a reference for further research on the physiological mechanism of heavy metal tolerance in plants.

Cadmium toxicity in plants and alleviation through seed priming approach

Cadmium toxicity in plants and alleviation through seed priming approach

Glutamate synthase 1 is involved in iron-deficiency response and long-distance transportation in Arabidopsis.

Iron is an essential microelement for plant growth. After uptake from the soil, iron is chelated by ligands and translocated from roots to shoots for subsequent utilization. However, the number of ligands involved in iron chelation is unclear. In this study, we identified and demonstrated that GLU1, which encodes a ferredoxin-dependent glutamate synthase, was involved in iron homeostasis. First, the expression of GLU1 was strongly induced by iron deficiency condition. Second, lesion of GLU1 results in reduced transcription of many iron-deficiency-responsive genes in roots and shoots. The mutant plants revealed a decreased iron concentration in the shoots, and displayed severe leaf chlorosis under the condition of Fe limitation, compared to wild-type. Third, the product of GLU1, glutamate, could chelate iron in vivo and promote iron transportation. Last, we also found that supplementation of glutamate in the medium can alleviate cadmium toxicity in plants. Overall, our results provide evidence that GLU1 is involved in iron homeostasis through affecting glutamate synthesis under iron deficiency conditions in Arabidopsis.

Cadmium toxicity and phytoremediation in trees - A review

Over time, the anthropic activity has contributed to alter biogeochemical cycle of heavy metals by releasing contaminants into water, soil and air. Due to contamination of environments with heavy metals, plants and animals consumed by population have presented some level of contamination, which has caused worries and also attempts to minimize these problem. Among heavy metals, cadmium is one of the most toxic to living creatures, occupying seventh position in toxic substances ranking, even with very low concentrations. One of measures adopted to reduce negative impact of soil contamination by heavy metals is phytoremediation. It consists of use of plants that tolerate presence of heavy metals in soil, absorbing, translocating and compartmentalizing them in aerial part, with little or no negative impact on plant growth. Among plants, trees are the most suitable for phytoremediation due to their considerable production of air biomass, which is associated with higher accumulation and consequently higher extraction of heavy metals. In this review, we address main nutritional, biochemical, physiological and molecular aspects of cadmium toxicity in plants, emphasizing role of trees in phytoremediation studies, especially recent studies on Khaya ivorensis or african mahogany and its cadmium phytoremediation potential.

Applications of carbon quantum dots to alleviate Cd2+ phytotoxicity in Citrus maxima seedlings

Heavy metal pollution may affect plant growth. The focus of this study was to explore remediation agents that alleviate cadmium toxicity in plants. The Citrus maxima (grapefruit) seedlings were cultivated for 10 days under hydroponic conditions amended with different concentrations of Cd2+ (50 and 200 mg/L) and CDs (600 and 900 mg/L). Our observations on roots and leaves showed that, the plant exposed to 200 mg/L Cd2+ alone was damaged, supported by the changes in anthocyanin contents, activity of antioxidant enzymes and cell membrane peroxidation damage (up to 35.8–45%). However, the physiological properties of the plant were improved upon exposed to 200 mg/L Cd2+ plus 900 mg/L CDs; it can be ascribed to Cd2+ sorption to the co-exposed CDs which reduced its freely dissolved concentration by more than 22.5%, thus significantly reducing the amount of Cd2+ entered the plant roots by 50.7–89.4%. Due to the oxidative stress induced by Cd2+ exposure at 200 mg/L, expression of glutathione-producing genes was up-regulated by 30–360% relative to the control, while the genes expression upon exposure to 200 mg/L Cd2+ and 900 mg/L CDs was reduced by 48.4–91.5% relative to that exposed to 200 mg/L Cd2+ alone. However, detoxification of CDs on plant leaves at 600 mg/L was insignificant, because a portion of Cd2+ taken up by roots can be transported to leaves associated with the internalized CDs. Therefore, CDs can be utilized as a repair agent to mitigate toxicity of Cd2+ to plant especially at a high amendment level (900 mg/L).

硅缓解植物镉毒害的生理生态机制

硅缓解植物镉毒害的生理生态机制

Physiological and proteomic analysis of selenium-mediated tolerance to Cd stress in cucumber (Cucumis sativus L.)

Selenium can mitigate cadmium toxicity in plants. However, the mechanism of this alleviation has not been fully understood. In the present study, the role of Se in inducing tolerance to Cd stress in cucumber was elucidated. Results showed that Se significantly alleviated Cd-induced growth inhibition, reduced Cd concentration, increased SPAD value and improved photosynthetic performance. Through proteomic analysis by two-dimensional gel electrophoresis (2-DE) coupled with mass spectrometry, 26 protein spots were identified, which were significantly influenced by Cd stress and/or Se application. Among these proteins, the abundance of 21 spots (10 in leaves and 11 in roots) were repressed in Cd-treated and up-accumulated or no-changed in Cd+Se-treated cucumber. These altered proteins were involved in the response to stress, metabolism, photosynthesis and storage, they were including glutathione S-transferase F8, heat shock protein STI-like, peroxidase, ascorbate oxidase, fructose-bisphosphate aldolase 2, NiR, Rieske type ion sulfur subunit and PsbP domain-containing protein 6. Furthermore, we identified five proteins with an increase in relative abundance after Cd treatment, they were involved in the functional groups active in response to stress and transport. The present study provided novel insights into Se-mediated tolerance of cucumber seedlings against Cd toxicity at the proteome level.

Cadmium Toxicity in Plants and Role of Mineral Nutrients in Its Alleviation

Cadmium (Cd) is a toxic heavy metal that enters the environment through various anthropogenic sources, and inhibits plant growth and development. Cadmium toxicity may result from disturbance in plant metabolism as a consequence of disturbance in the uptake and translocation of mineral nutrients. Plant nutrients and Cd compete for the same transporters and, therefore, presence of Cd results in mineral nutrients deficiency. The optimization of mineral nutrients under Cd stress could reduce Cd toxicity by greater availability at the transport site resulting in reduced accumulation of Cd, and could also alleviate Cd-induced toxic effects by enhancing biochemical reactions and physiological processes in plants. In the present review the role of plant macro, micro and beneficial elements in alleviating Cd stress in crop plants is discussed.

The message of nitric oxide in cadmium challenged plants

During the last decade it has been found that cadmium (Cd), one of the most toxic elements occurring in polluted environments, interferes with nitric oxide (NO), a multifunctional signaling molecule in living organisms. The formation of NO has been demonstrated in vivo in various plant tissues exposed to Cd stress, but unfortunately, the time and intensity of NO generation, relatively frequently shows conflicting data. What is more, there is still limited information regarding the functional role of endogenously produced NO in plants challenged with heavy metals. The first pharmacological approaches revealed that exogenously applied NO can alleviate cadmium toxicity in plants, promoting the direct scavenging of reactive oxygen species (ROS) or activating antioxidant enzymes. However, recent reports have indicated that NO even contributes to Cd toxicity by promoting Cd uptake and participates in metal-induced reduction of root growth. In view of this heterogeneous knowledge, much more puzzling if we consider results first obtained using exogenous NO sources, this review is focused mainly on the implication of endogenous NO in plant response to Cd exposure. Furthermore, a basic draft for NO mode of action during cadmium stress is proposed.

Cadmium Toxicity in Plants: Is There any Analogy to its Carcinogenic Effect in Mammalian Cells?

Cadmium is a heavy metal, which is classified as a human carcinogen and is known to be toxic to plants. However, plants do not respond to this metal by massive cell proliferation. In this review the various aspects of cadmium toxicity in plants are compared to related processes in mammalian cells. The following issues are discussed: cellular uptake of Cd ions, their intracellular transport, the effects on cellular signaling, nucleic acids and proteins, modification of gene expression, cell cycle control and apoptosis. Reviewed data suggest that such features as: ability to remove the oxidized proteins, slightly different regulation of cell cycle genes, specific pattern of apoptosis, makes plants resistant to Cd(2+)-induced uncontrolled cell proliferation.

EDXRF and TXRF application to cadmium toxicity in Acer pseudoplatanus L. cells: cytological features and cation interactions

AbstractCadmium is one of the most toxic heavy metals that can be taken up by plants. Although cadmium toxicity in plants is well established, the mechanism of Cd actions at the cell level is not entirely known. The aim of this work was the investigation of Cd effects on cation contents (K, Ca, Mn, Fe, Cu, Zn) and cytological changes in sycamore cells (Acer pseudoplatanus L.). Sycamore cells were treated with 20 µM CdSO4, a sub‐lethal concentration, for 7 days. Energy‐dispersive x‐ray fluorescence (EDXRF) spectrometry was applied to quantify cation concentrations in cells. Cd concentration was measured by total reflection x‐ray fluorescence (TXRF) spectrometry. The quantification was performed with cells taken directly from the culture and also after being washed in an acidified medium. Light and scanning microscope observations showed several modifications of cadmium‐treated cells, namely increased cell volume and vacuolation. Cells exposed to cadmium also showed variations in cation concentrations. An increase in Mn, Fe, Cu and Zn contents and a decrease in K content were observed in Cd‐stressed cells. Fe was the most increased element, followed by Mn and Cu and a similar behaviour was observed for Ca and Zn. K was the only cation showing a decreased concentration under Cd stress. The high levels of Cd in cells exposed to Cd are in agreement with the amount of Cd accumulated within the cells. The results obtained allowed differentiation between adsorption of ions on the cell wall and uptake of ions into the intracellular compartments. Copyright © 2005 John Wiley & Sons, Ltd.

Cadmium toxicity in plants

Heavy metals are important environmental pollutants and their toxicity is a problem of increasing significance for ecological, evolutionary, nutritional, and environmental reasons. Plants posses homeostatic cellular mechanisms to regulate the concentration of metal ions inside the cell to minimize the potential damage that could result from the exposure to nonessential metal ions. This paper summarizes present knowledge in the field of higher plant responses to cadmium, an important environmental pollutant. Knowledge concerning metal toxicity, including mechanisms of cadmium homeostasis, uptake, transport and accumulation are evaluated. The role of the cell wall, the plasma membrane and the mycorrhizas, as the main barriers against cadmium entrance to the cell, as well as some aspects related to phytochelatin-based sequestration and compartmentalization processes are also reviewed. Cadmium-induced oxidative stress was also considered as one of the most studied topics of cadmium toxicity.