The impact of chromium toxicity on the yield and quality of rice grains produced under ambient and elevated levels of CO2

Unraveling the role of κ-carrageenan on the combined effect of drought and chromium stress in wheat (Triticum aestivium L.)

Drought (D) and chromium (Cr) stress co-occur in agricultural fields due to the accumulation of excessive Cr in soils from industrial pollution and increasing frequency of water scarcity. Carrageenan (Car), a compound extracted from red seaweed, is an emerging biostimulant with multifaceted roles in plants. This study investigated the role of exogenous Car in mediating tolerance to D-, Cr-, and DCr-stress in wheat seedlings, aiming to elucidate the potential of Car in mitigating toxicity and promoting plant resilience. Wheat seedlings exposed to DCr-stress exhibited reduced growth and biomass production, along with elevated levels of reactive oxygen, carbonyl, and nitrogen species. Moreover, D-stress exacerbated Cr-toxicity, as demonstrated by principal component analysis (PCA), which showed a strong positive correlation between DCr-stress and stress marker parameters. This suggests that DCr-stress resulted in higher Cr uptake and increased oxidative damage compared to individual D- or Cr-stress, making DCr-stress more detrimental than either stress applied alone. However, Car priming ameliorated the toxic effects of DCr-stress and promoted the growth performance of DCr-stressed wheat seedlings. In PCA, the positive correlation of D + Car, Cr + Car, and DCr + Car treatments with growth and plant defense-related parameters suggests that Car-mediated improvement in stress tolerance can be attributed to reduced accumulation of toxic Cr, increased levels of total free amino acids and soluble sugars, enhanced antioxidant enzyme activity, elevated non-enzymatic antioxidant levels, higher phenolic and flavonoid content, and improved metal chelation and detoxification. Our results indicated Car is a potential and cost-effective biostimulant for managing D-, Cr-, or DCr-stress in wheat.

Carbon dioxide-enriched atmosphere diminished the phytotoxicity of neodymium in wheat (Triticum aestivum L.)

Introduction

Neodymium (Nd), a rare earth element (REEs), is widely utilized in industry. Although the detailed biological role of Nd in plant biology is unclear, recent reports have noted its oxidative phytotoxicity at concentrations higher than 200 mg kg-1 soil. At present it is unclear if these detrimental effects could be offset by the global rise in atmospheric carbon dioxide concentration ([CO2]) which has been shown to enhance photosynthesis and growth in a wide range of C3 plant species.

Methods

To assess any amelioration effects of [CO2], a phytotoxic dose of Nd (III) was given to wheat grown under two scenarios of atmospheric CO2, ambient levels of CO2 (aCO2, 420 ppm) and eCO2 (620 ppm) to assess growth and photosynthesis.

Results and discussion

Our results suggest that at ambient [CO2], Nd treatment retarded wheat growth, photosynthesis and induced severe oxidative stress. In contrast, eCO2 reduced the accumulation of Nd in wheat tissues and mitigated its negative impact on biomass production and photosynthesis related parameters, i.e., photosynthetic rate, chlorophyll content, Rubisco activity and photochemical efficiency of PSII (Fv/Fm). Elevated [CO2] also supported the antioxidant defense system in Nd-treated wheat, enhanced production of enzymatic antioxidants, and more efficient ascorbate-glutathione recycling was noted. While additional data are needed, these initial results suggest that rising [CO2] could reduce Nd-induced oxidative stress in wheat.

Metabolomic responses of wheat grains to olive mill wastewater and drought stress treatments

The present research aimed to assess the metabolomic responses of wheat to olive mill wastewater (OMWW) and drought stress treatments. Wheat plants were cultivated under controlled conditions with the following treatments: control (75% field capacity, FC), OMWW (75 ml L-1), drought stress (40% FC, applied 30 days after sowing), and a combined treatment of OMWW and drought stress. Drought stress alone reduced grain yield by 67%, while the OMWW-treated plants resulted in a 29% reduction under stress relative to the control. OMWW application improved soil properties, enhancing organic matter and nutrient levels. Wheat grains from OMWW-treated plants exhibited higher sugar content and related enzyme activities, indicating improved metabolism, with significant increases in starch, fructose, and glucose levels alongside stable invertase and sucrose phosphate synthase activities. The study also noted substantial changes in amino acids, fatty acids, and phenolic acids in plants subjected to OMWW and drought stress. These modifications indicate OMWW's capability to influence vital biochemical pathways and boost antioxidant capacities in wheat. In conclusion, OMWW proves to be an effective soil amendment that mitigates drought stress and contributes to the production of nutrient-rich, resilient wheat, underscoring its potential as a sustainable agricultural practice in water-scarce areas.

Microbial mechanisms of interactive climate-driven changes in soil N2O and CH4 fluxes: A global meta-analysis

Soils represent both a source of and sink for greenhouse gases (GHG). Elevated temperature (eT) affects both the physical and biological factors that drive GHG emissions from soil and thus understanding the effects of rising global temperatures on terrestrial GHG emission is needed to predict future GHG emissions, and to identify mitigation strategies. However, uncertainty remains about the interactive effects of multiple climate factors across different ecosystems, complicating our ability to develop robust climate change projections. Therefore, a global meta-analysis of 1337 pairwise observations from 150 peer-reviewed publications (1990-2023) was conducted to assess the individual effect of eT and its combined effects with eCO2 (eT + eCO2), drought (eT + drought) and increased precipitation (eT + ePPT) on soil N2O and CH4 fluxes, microbial functional genes, and soil extracellular enzyme activities across grassland, cropland, and forestland ecosystems. Across the dataset, eT significantly increased N2O emissions (21%) and CH4 uptake (36%). Nitrogen cycling was consistently stimulated by eT, with NO3- and NH4+ and the abundance of amoA-AOB gene increasing by 6%, 10%, and 18%, respectively. Soil water content (SWC) was reduced, whereas increases of 9% in soil organic carbon (SOC), 14% in microbial biomass carbon (MBC), and 10% in total plant biomass were found under eT. The stimulation of soil N2O emissions by eT was maintained for all ecosystems when combined with other global change factors (ie., eT + eCO2, eT + ePPT, and eT + drought). By contrast, effects of eT on CH4 uptake and emissions were more variable when combined with other factors; for instance, eT + eCO2 and eT + ePPT suppressed CH4 uptake in grasslands. This study highlights the urgent need to study the microbial mechanisms responsible for combined global change effects on N2O and especially CH4 fluxes.

Differential AMF-mediated biochemical responses in sorghum and oat plants under environmental impacts of neodymium nanoparticles

This study investigates the impact of neodymium (Nd) nanoparticle (NdNP) toxicity on the physiological and biochemical responses of sorghum (Sorghum bicolor) and oat (Avena sativa) plants and evaluates the potential mitigating effects of arbuscular mycorrhizal fungi (AMF). Sorghum and oat plants were grown under controlled conditions with and without AMF inoculation, and subjected to NdNPs (500 mg Nd kg-1 soil). Results revealed that Nd nanoparticles significantly reduced biomass in both species, with a 50% decrease in sorghum and a 59% decrease in oats. However, AMF treatment ameliorated these effects, increasing biomass by 69% in oats under Nd nanoparticles toxicity compared to untreated contaminated plants. Soluble sugar metabolism was notably affected; AMF treatment led to significant increases in fructose and sucrose contents in both sorghum (+31% and +23%, respectively) and oat (+25% and +37%, respectively) plants under NdNPs toxicity. Improved sugar metabolism via enhanced activities of sucrose phosphate synthase (+29-54%) and invertase (+39-54%) enzymes resulted in higher proline (+21-81%) and polyamines (+49-52%) levels in AMF-treated plants under NdNPs toxicity, along with alterations in the biosynthesis pathways of amino acids and fatty acids, resulting in better osmoprotection and stress tolerance. Moreover, citrate (+29-55%) and oxalate (+177-312%) levels increased in both plants in response to NdNPs toxicity, which was accompanied by a positive response of isobutyric acid to AMF treatment in stressed plants, which potentially might serve as mechanisms for plants to mitigate NdNPs toxicity. These findings suggest that AMF can significantly mitigate Nd-induced damage and improve plant resilience through enhanced metabolic adjustments, highlighting a potential strategy for managing rare earth element (REE) nanoparticle toxicity in agricultural soils.

Rice bran: Nutritional value, health benefits, and global implications for aflatoxin mitigation, cancer, diabetes, and diarrhea prevention

Rice (Oryza sativa) is a staple food crop with a rich history and significant contributions to global nutrition. This study examines the production of rice and rice bran, focusing on their nutritional profiles, bioactive compounds, and the lack of proper guidelines for aflatoxins and arsenic in rice products. Rice bran's potential as a dietary supplement, particularly in addressing nutrient deficiencies and diseases, is highlighted. Arsenic contamination, a critical food safety issue, is discussed, as their accumulation poses significant risks, including cancer, cardiovascular diseases, and developmental problems. This overview addresses aflatoxin and arsenic contamination, threatening rice's safety and by-products. The structure and characteristics of rice bran, including types of grain polishing, stabilization processes, and toxic elements, are also analyzed. Factors affecting the bioavailability of nutrients, such as pesticide residues and storage conditions, are considered. The review emphasizes the antioxidant properties of rice milling by-products, particularly pigmented rice varieties rich in bioactive compounds. It offers health benefits such as cancer prevention, anti-diarrheal effects, and anti-diabetic properties. This comprehensive analysis underscores rice bran's nutritional and therapeutic value, advocating for its broader utilization to enhance global health and combat nutrient deficiencies.

Morpho-Physiological Adaptations of Rice Cultivars Under Heavy Metal Stress: A Systematic Review and Meta-Analysis

Soil contamination, including in rice fields, arises from a variety of natural processes and anthropogenic activities, leading to an accumulation of heavy metals. While extensive research has addressed the bioaccumulation of heavy metals in rice, only limited systematic reviews have examined their specific impact on the morpho-physiological traits of rice plants. This review aims to provide a comprehensive synthesis of current studies detailing the rice cultivars, types of heavy metals investigated, study designs, sampling locations, and experimental sites while systematically analyzing the morphological and physiological responses of rice cultivars to heavy metal stress. Studies show that morphological traits generally exhibit a decline under heavy metal exposure. Physiologically, rice cultivars tend to show decreased total chlorophyll and carotenoid levels, along with increased levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), and proline. These findings suggest that plant genotype, type of heavy metal, and intensity of stress significantly modulate the morphological and physiological responses of rice, highlighting critical areas for further research in heavy metal stress tolerance in rice cultivars.

Zinc-lysine and iron-lysine mitigate chromium toxicity in pearl millet (Pennisetum glaucum) through modulating photosynthetic and antioxidant system and inhibiting chromium uptake and translocation

Chromium (Cr) is an ever-present abiotic stress that negatively affects crop cultivation and production worldwide. High rhizospheric Cr concentrations inhibit nutrients uptake and their translocation to aboveground parts, thus can affect the growth and development of crop plants. This experiment was designed to evaluate the effects of sole and combined zinc-lysine and iron-lysine applications on photosynthetic efficacy, antioxidative defense, oxidative stress, and nutrient uptake and translocation under Cr stress. Chromium stress exhibited toxic effects on the growth, physiological, and biochemical indices of pearl millet. The combined application of zinc-lysine and iron-lysine significantly decreased malondialdehyde (MDA; 25%) and hydrogen peroxide (H2O2; 22.44%), while increased superoxide dismutase (SOD; 19.75%), catalase (CAT; 26.16%), peroxidase (POD; 19.62%), and ascorbate peroxidase (APX; 23.52%) activities under Cr toxicity compared to the control treatment. In addition, the combined application of zinc-lysine and iron-lysine effectively improved net photosynthesis (43.63%), stomatal conductance (20.05%), transpiration rate (20.14%), internal CO2 concentration (34.28%), total chlorophyll (43.12%), relative water content (23.95%), membrane stability index (32.77%), and proline content (25.53%) under stress condition and compared with control. Our results also indicated that the combined application of zinc-lysine and iron-lysine decreased Cr uptake in both shoot and root by 31.25% and 32%, and increased zinc and iron uptake by 39.28% and 36.67%, respectively, over the control, under Cr stress conditions. Moreover, under stress conditions, combined zinc-lysine and iron-lysine effectively improved growth traits particularly shoot and root dry weights, by 8% and 36.84%, respectively, over the control treatment. Overall, our results demonstrated that combined zinc-lysine and iron-lysine was more effective in mitigating Cr toxicity in pearl millet compared with the sole application of these treatments or the control.

Alleviation of cadmium toxicity by improving antioxidant defense mechanism and nutrient uptake in wheat (Triticum aestivum L.) through foliar application of 24-epibrassinolide under elevated CO2

Heavy metals like cadmium (Cd) contamination occur in conjunction with the rising CO2 threatening food security and safety. Foliar application of 24-Epibrassinolide (EBR) was found to ameliorate Cd stress and improve nutrient availability in crops. However, its role under elevated CO2 is currently unknown. Accordingly, a pot experiment was conducted in open-top chambers (CO2 at 400 and 600 μmol mol-1) to determine the protective effect of EBR on wheat plants under different Cd concentrations (0, 2, and 4 mg kg-1) in soil. The foliar application of EBR significantly improved growth, biomass, photosynthesis, proline, total phenol, and total soluble protein in Cd stress treatments under elevated CO2. Simultaneously, it significantly (p ≤ 0.05) increased catalase (42.89 %), superoxide dismutase (26.53 %), peroxidase (28.10 %), and ascorbate peroxidase (61.70 %) while reduced malondialdehyde (35.53 %), hydrogen peroxide (19.94 %), and electrolyte leakage (23.55 %) under elevated CO2 compared to ambient CO2 conditions. Furthermore, EBR and elevated CO2 interactively showed a maximum reduction in Cd concentrations and accumulation in the wheat roots (39.74,41.63 %), shoots (46.83,44.87 %), and grains (27.52,29.06 %) respectively. Elevated CO2 and Cd stress interactively showed a significant reduction in nutrient content. Conversely, the EBR application recovered and significantly increased calcium, magnesium, iron, zinc, and copper content in wheat roots, shoots, and grains. Our findings inferred that EBR foliar application reduced Cd toxicity and improved plant growth and nutritional quality under elevated CO2.

Morphophysiological, biochemical, and nutrient response of spinach (Spinacia oleracea L.) by foliar CeO2 nanoparticles under elevated CO2

Nanomaterials offer considerable benefits in improving plant growth and nutritional status owing to their inherent stability, and efficiency in essential nutrient absorption and delivery. Cerium oxide nanoparticles (CeO2 NPs) at optimum concentration could significantly influence plant morpho-physiology and nutritional status. However, it remains unclear how elevated CO2 and CeO2 NPs interactively affect plant growth and quality. Accordingly, the ultimate goal was to reveal whether CeO2 NPs could alter the impact of elevated CO2 on the nutrient composition of spinach. For this purpose, spinach plant morpho-physiological, biochemical traits, and nutritional contents were evaluated. Spinach was exposed to different foliar concentrations of CeO2 NPs (0, 25, 50, 100 mg/L) in open-top chambers (400 and 600 CO2 μmol/mol). Results showed that elevated CO2 enhanced spinach growth by increasing photosynthetic pigments, as evidenced by a higher photosynthetic rate (Pn). However, the maximum growth and photosynthetic pigments were observed at the highest concentration of CeO2 NPs (100 mg/L) under elevated CO2. Elevated CO2 resulted in a decreased stomatal conductance (gs) and transpiration rate (Tr), whereas CeO2 NPs enhanced these parameters. No significant changes were observed in any of the measured biochemical parameters due to increased levels of CO2. However, an increase in antioxidant enzymes, particularly in catalase (CAT; 14.37%) and ascorbate peroxidase (APX; 10.66%) activities, was observed in high CeO2 NPs (100 mg/L) treatment under elevated CO2 levels. Regarding plant nutrient content, elevated CO2 significantly decreases spinach roots and leaves macro and micronutrients as compared to ambient CO2 levels. CeO2 NPs, in a dose-dependent manner, with the highest increase observed in 100 mg/L CeO2 NPs treatment and increased roots and shoots magnesium (211.62-215.49%), iron (256.68-322.77%), zinc (225.89-181.49%), copper (21.99-138.09%), potassium (121.46-138.89%), calcium (118.22-91.32%), manganese (133.15-195.02%) under elevated CO2. Overall, CeO2 NPs improved spinach growth and biomass and reverted the adverse effects of elevated CO2 on its nutritional quality. These findings indicated that CeO2 NPs could be used as an effective approach to increase vegetable growth and nutritional values to ensure food security under future climatic conditions.

Mitigating gadolinium toxicity in guar (Cyamopsis tetragonoloba L.) through the symbiotic associations with arbuscular mycorrhizal fungi: physiological and biochemical insights

BACKGROUND

Gadolinium (Gd) is an increasingly found lanthanide element in soil; thus, understanding its impact on plant physiology, biochemistry, and molecular responses is crucial. Here, we aimed to provide a comprehensive understanding of Gd (150 mg kg- 1) impacts on guar (Cyamopsis tetragonoloba L.) plant yield and metabolism and whether the symbiotic relationship with arbuscular mycorrhizal fungi (AMF) can mitigate Gd toxicity of soil contamination.

RESULTS

AMF treatment improved mineral nutrient uptake and seed yield by 38-41% under Gd stress compared to non-inoculated stressed plants. Metabolic analysis unveiled the defense mechanisms adopted by AMF-treated plants, revealing carbon and nitrogen metabolism adaptations to withstand Gd contamination. This included an increase in the synthesis of primary metabolites, such as total sugar (+ 39% compared to control), soluble sugars (+ 29%), starch (+ 30%), and some main amino acids like proline (+ 57%) and phenylalanine (+ 87%) in the seeds of AMF-treated plants grown under Gd contamination. Furthermore, fatty acid and organic acid profile changes were accompanied by the production of secondary metabolites, including tocopherols, polyamines, phenolic acids, flavones, and anthocyanins.

CONCLUSIONS

Overall, the coordinated synthesis of these compounds underscores the intricate regulatory mechanisms underlying plant-AMF interactions and highlights the potential of AMF to modulate plant secondary metabolism for enhanced Gd stress tolerance.

Zn-Al and Mg-Al layered double hydroxide nanoparticles improved primary and secondary metabolism of geranium plants

Layer double hydroxide (LDH) nanoparticles (NPs) have been applied to enhance plant growth and productivity. However, their effects on carbon and nitrogen metabolism of aromatic plants, are not well understood. Therefore, we investigated the impact of foliar application of Zn-Al LDH and Mg-Al LDH NPs (10 ppm) on the growth and metabolism of geranium plants. Zn-Al LDH and Mg-Al LDH NPs significantly increased the dry biomass, photosynthetic pigment, and Zn and Mg uptake by treated plants. These increases were consistent with increased primary metabolism such as soluble sugars and their metabolic enzymes (invertase and amylase). The supply of high sugar levels induced TCA organic accumulation, providing a pathway for amino acid biosynthesis. Among amino acids, proline level and its biosynthetic enzymes such as pyrroline-5-carboxylate reductase (P5CR), ornithine aminotransferase (OAT), and pyrroline-5-carboxylate synthetase (P5CS), glutamine synthetase (GS), and arginase were increased. Increased primary metabolites can then be channeled into secondary metabolic pathways, leading to higher levels of secondary metabolites including tocopherols, phenolics, and flavonoids. These observed increases in primary and secondary metabolites also improve the biological value of geranium plants. Overall, our research highlights the potential of Zn-Al LDH and Mg-Al LDH NPs as elicitors to enhance metabolism in geranium plants, thereby improving their growth bioactivity.

Mitigating chromium toxicity in rice (Oryza sativa L.) via ABA and 6-BAP: Unveiling synergistic benefits on morphophysiological traits and ASA-GSH cycle

In recent years, the use of plant hormones, such as abscisic acid (ABA) and 6-benzylaminopurine (6-BAP), has gained significant attention for their role in mitigating abiotic stresses across various plant species. These hormones have been shown to play a vital role in enhancing the ascorbate-glutathione cycle and eliciting a wide range of plant growth and biomass, photosynthetic efficiency, oxidative stress and response of antioxidants and other physiological responses. While previous research has been conducted on the individual impact of ABA and 6-BAP in metal stress resistance among various crop species, their combined effects in the context of heavy metal-stressed conditions remain underexplored. The current investigation is to assess the beneficial effects of single and combined ABA (5 and 10 μM L-1) and 6-BAP (5 and 10 μM L-1) applications in rice (Oryza sativa L.) cultivated in chromium (Cr)-contaminated soil (100 μM). Our results showed that the Cr toxicity in the soil showed a significant declined in the growth, gas exchange attributes, sugars, AsA-GSH cycle, cellular fractionation, proline metabolism in O. sativa. However, Cr toxicity significantly increased oxidative stress biomarkers, organic acids, enzymatic and non-enzymatic antioxidants including their gene expression in O. sativa seedlings. Although, the application of ABA and 6-BAP showed a significant increase in the plant growth and biomass, gas exchange characteristics, enzymatic and non-enzymatic compounds and their gene expression and also decreased the oxidative stress, And Cr uptake. In addition, individual or combined application of ABA and 6-BAP enhanced the cellular fractionation and decreases the proline metabolism and AsA-GSH cycle in rice plants. These results open new insights for sustainable agriculture practices and hold immense promise in addressing the pressing challenges of heavy metal contamination in agricultural soils.

Elevated CO2 reduced antimony toxicity in wheat plants by improving photosynthesis, soil microbial content, minerals, and redox status

Introduction

Antimony (Sb), a common rare heavy metal, is naturally present in soils at low concentrations. However, it is increasingly used in industrial applications, which in turn, leads to an increased release into the environment, exerting a detrimental impact on plant growth. Thus, it is important to study Sb effects on plants under the current and future CO2 (eCO2).

Methods

To this end, high Sb concentrations (1500 mg/kg soil) effects under ambient (420 ppm) and eCO2 (710 ppm) on wheat growth, physiology (photosynthesis reactions) and biochemistry (minerals contents, redox state), were studied and soil microbial were evaluated.

Results and discussion

Our results showed that Sb uptake significantly decreased wheat growth by 42%. This reduction could be explained by the inhibition in photosynthesis rate, Rubisco activity, and photosynthetic pigments (Cha and Chb), by 35%, 44%, and 51%, respectively. Sb significantly reduced total bacterial and fungal count and increased phenolic and organic acids levels in the soil to decrease Sb uptake. Moreover, it induced oxidative markers, as indicated by the increased levels of H2O2 and MDA (1.96 and 2.8-fold compared to the control condition, respectively). To reduce this damage, antioxidant capacity (TAC), CAT, POX, and SOD enzymes activity were increased by 1.61, 2.2, 2.87, and 1.86-fold, respectively. In contrast, eCO2 mitigated growth inhibition in Sb-treated wheat. eCO2 and Sb coapplication mitigated the Sb harmful effect on growth by reducing Sb uptake and improving photosynthesis and Rubisco enzyme activity by 0.58, 1.57, and 1.4-fold compared to the corresponding Sb treatments, respectively. To reduce Sb uptake and improve mineral availability for plants, a high accumulation of phenolics level and organic acids in the soil was observed. eCO2 reduces Sb-induced oxidative damage by improving redox status. In conclusion, our study has provided valuable insights into the physiological and biochemical bases underlie the Sb-stress mitigating of eCO2 conditions. Furthermore, this is important step to define strategies to prevent its adverse effects of Sb on plants in the future.

Soil Contamination with Europium Induces Reduced Oxidative Damage in Hordeum vulgare Grown in a CO2-Enriched Environment

The extensive and uncontrolled utilization of rare earth elements, like europium (Eu), could lead to their accumulation in soils and biota. Herein, we investigated the impact of Eu on the growth, photosynthesis, and redox homeostasis in barley and how that could be affected by the future CO2 climate (eCO2). The plants were exposed to 1.09 mmol Eu3+/kg soil under either ambient CO2 (420 ppm, aCO2) or eCO2 (620 ppm). The soil application of Eu induced its accumulation in the plant shoots and caused significant reductions in biomass- and photosynthesis-related parameters, i.e., chlorophyll content, photochemical efficiency of PSII, Rubisco activity, and photosynthesis rate. Further, Eu induced oxidative stress as indicated by higher levels of H2O2 and lipid peroxidation products, and lower ASC/DHA and GSH/GSSG ratios. Interestingly, the co-application of eCO2 significantly reduced the accumulation of Eu in plant tissues. Elevated CO2 reduced the Eu-induced oxidative damage by supporting the antioxidant defense mechanisms, i.e., ROS-scavenging molecules (carotenoids, flavonoids, and polyphenols), enzymes (CAT and peroxidases), and ASC-GSH recycling enzymes (MDHAR and GR). Further, eCO2 improved the metal detoxification capacity by upregulating GST activity. Overall, these results provide the first comprehensive report for Eu-induced oxidative phytotoxicity and how this could be mitigated by eCO2.