Journal articles on the topic 'Mn toxicity'
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1
Mortley, Desmond G. "MANGANESE TOXICITY OR TOLERANCE IN SWEETPOTATO." HortScience 27, no. 6 (June 1992): 665e—665. http://dx.doi.org/10.21273/hortsci.27.6.665e.
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Greenhouse studies were conducted to evaluate 5 levels of Mn (0.00025 to 0.1 g.L-1) on Mn toxicity or tolerance of sweetpotato [Ipomoea batatas (L.) Lam] grown in a modified half Hoagland's solution. The presence of oxidized Mn on the roots and leaves was demonstrated by the blue staining test with benzidene and the solubility and bleaching of oxidized Mn in the oxalic-sulfuric acid solution. Both storage root and foliage fresh and dry weights were highest at Mn concn of 0.00025 g.L-1 in the nutrient solution, while fibrous root dry weight was highest with 0.01 g.L-1 Mn in the solution. More Mn accumulated in foliage than in fibrous roots for all levels of Mn evaluated. N, P, and K concn in foliage was highest at a Mn concn of 0.1 g.L-1 Mn in the solution. Foliage dry weight was preserved up to a high Mn level of about 2700 ug. g-1 Mn in tissues, while taht for storage roots was preserved up to a high Mn level of about 1000 ug. g-1 in the tissues. Deposition of oxidized Mn was observed on fibrous roots particularly at the highest Mn levels in the nutrient solution.
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Elamin, Osman M., and Gerald E. Wilcox. "Effect of Magnesium and Manganese Nutrition on Muskmelon Growth and Manganese Toxicity." Journal of the American Society for Horticultural Science 111, no. 4 (July 1986): 582–87. http://dx.doi.org/10.21273/jashs.111.4.582.
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Abstract Muskmelons (Cucumis melo L.) ‘Harvest Queen’ were grown in sand culture to evaluate the response to Mn toxicity as affected by solution concentration of Mn and Mg. Manganese toxicity symptoms were developed as water-soaked spots, necrotic spots, and necrotic lesions, which were most severe on the lower mature leaves. Leaves developed toxicity symptoms when they contained ≥900 μ-g·g-1 Mn. Increased levels of Mg in the nutrient solution alleviated symptoms of Mn toxicity, decreased Mn concentration in shoot and root tissues, and increased growth of muskmelon plants. The reduction in Mn toxicity was brought about by reduced root absorption of Mn at high Mg supply.
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Mortley, Desmond G. "Manganese Toxicity and Tolerance in Sweetpotato." HortScience 28, no. 8 (August 1993): 812–13. http://dx.doi.org/10.21273/hortsci.28.8.812.
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The effects of 0.25, 1.0, 2.5, 10, and 100 mg Mn/liter on sweetpotato [Ipomoea batatas (L.) Lam] were evaluated in a greenhouse during 2 years using the nutrient film technique. Foliage and storage root dry weights declined linearly as Mn concentration increased in either whole plants or fibrous roots. Foliage and storage root dry weights were equally sensitive to Mn concentration in whole plants but 5 to 15 times more sensitive to increased Mn concentration in the fibrous roots. Foliar N, P, K, Ca, and Mg concentrations were adequate and did not appear to limit plant growth. Manganese concentrations in solution had very little effect on Fe, Zn, or B concentration. Manganese concentration was higher in the foliage than in fibrous roots. Plant roots showed browning at the higher (10 or 100 mg Mn/liter) concentrations in solution, which indicated the presence of oxidized Mn. Characteristic toxicity symptoms were observed in plants receiving 2.5 (moderate), 10, or 100 mg Mn/liter in solution.
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Elamin, Osman M., and Gerald E. Wilcox. "Manganese Toxicity Development in Muskmelons as Influenced by Nitrogen Form." Journal of the American Society for Horticultural Science 111, no. 3 (May 1986): 323–27. http://dx.doi.org/10.21273/jashs.111.3.323.
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Abstract Muskmelon (Cucumis melo L.) ‘Harvest Queen’ seedlings were grown in sand culture at 2, 15, or 30 ppm Mn with 3 different N treatments to evaluate the effects of N form on growth, composition, and development of Mn toxicity. Nitrogen treatments consisted of NO3, NH4, and NH4 shifted to NO3 at 5 days, when Mn toxicity symptoms began to show on NO3-treated plants. Muskmelons produced the most growth with N supplied as NO3, least growth with NH4, and intermediate growth with the NH4-to-NO3 shift treatment. Plants grown with NO3-N at 15 or 30 ppm of Mn had restricted growth, developed Mn toxicity symptoms 5 days after the start of Mn treatments, and had a Mn composition of over 1500 ppm in dry shoot tissue. With NH4 the Mn treatments had no effect on growth, no Mn toxicity symptoms developed, and Mn composition of shoot tissue was <800 ppm. Shifting plants from NH4 to NO3-N resulted in the development of Mn toxicity symptoms and tissue Mn composition over 1500 ppm within 4 days after the shift.
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Elamin, Osman M., and Gerald E. Wilcox. "Manganese Toxicity in Watermelon Plants as Influenced by Nitrogen Form." Journal of the American Society for Horticultural Science 111, no. 5 (September 1986): 765–68. http://dx.doi.org/10.21273/jashs.111.5.765.
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Abstract Watermelon [Citrullus lanatus (Thunb.)] ‘Sugar Baby’ seedlings were grown in sand culture leached with nutrient solution containing 2, 25, or 50 mg·liter−1 Mn in combination with NH4 or NO3-N to evaluate the effects of N form on growth, composition, and development of Mn toxicity. Nitrogen form treatments consisted of continuous NO3, continuous NH4, and a treatment in which NH4 was replaced by NO3 after Mn toxicity symptoms were first observed on NO3-treated plants. Watermelon plants produced the most growth at all Mn levels with N supplied as NO3, least with NH4, and intermediate with the NH4-to-NO3 shift treatment. Plants grown with NO3-N at 25 and 50 mg·liter−1 Mn had reduced growth and developed Mn toxicity symptoms with Mn concentrations >1700 μg·g−1 in shoot tissues. However, with NH4 the Mn treatments had no effect on growth, no Mn toxicity symptoms developed, and Mn concentrations in shoot tissue were <800 μg·g−1. Shifting plants from NH4-to-NO3 nutrition at 50 mg·liter−1 Mn in solution stimulated rapid Mn absorption and produced Mn toxicity symptoms within 3 days.
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Gong, Jian, Dong Li, Hao Li, Huakun Zhou, and Jin Xu. "Identification of manganese-responsive microRNAs in Arabidopsis by small RNA sequencing." Czech Journal of Genetics and Plant Breeding 55, No. 2 (May 22, 2019): 76–82. http://dx.doi.org/10.17221/57/2018-cjgpb.
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Manganese (Mn) is an important micronutrient for growth and development in plants, however, excess Mn is harmful by disrupting photosynthesis system and inducing oxidative damage in leaves. MicroRNAs (miRNAs) play key roles in regulating Mn toxicity tolerance in plants. Here, we identified Mn toxicity-responsive miRNAs in Arabidopsis by using small RNA sequencing. Eighteen differentially expressed miRNAs were identified in Arabidopsis thaliana seedlings in response to Mn toxicity. These differentially expressed miRNAs are involved in regulating nutrition homeostasis, transport, stress response, and developmental processes. Our results indicated that these miRNAs play a key role in Mn toxicity response in plants.
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Paľove-Balang, P., A. Kisová, J. Pavlovkin, and MistríkI. "Effect of manganese on cadmium toxicity in maize seedlings." Plant, Soil and Environment 52, No. 4 (November 15, 2011): 143–49. http://dx.doi.org/10.17221/3358-pse.
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The interaction of manganese with cadmium (Cd) toxicity was studied on maize plants grown in hydroponics. Manganese supplied as MnSO<sub>4</sub>clearly alleviated the toxic effect of cadmium on the root growth of maize seedlings. The magnitude of alleviation was dose dependant and total abolition of 10µM Cd toxicity on root growth was observed at Mn/Cd ratio of 20:1. The 12 h pre-treatment with 10μM Cd was generally toxic for nitrate uptake and reduction (both determined in Cd-free media). The beneficial effect of 100μM Mn on this toxicity was confirmed for the low-affinity nitrate uptake system, but on the other hand, Mn alone seems to be slightly toxic for high affinity nitrate uptake system and on the nitrate reductase activity.
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Liu, Ying, Min Zhao, Jingye Chen, Shaoxia Yang, Jianping Chen, and Yingbin Xue. "Comparative Transcriptome Analysis Reveals Complex Physiological Response and Gene Regulation in Peanut Roots and Leaves under Manganese Toxicity Stress." International Journal of Molecular Sciences 24, no. 2 (January 6, 2023): 1161. http://dx.doi.org/10.3390/ijms24021161.
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Excess Manganese (Mn) is toxic to plants and reduces crop production. Although physiological and molecular pathways may drive plant responses to Mn toxicity, few studies have evaluated Mn tolerance capacity in roots and leaves. As a result, the processes behind Mn tolerance in various plant tissue or organ are unclear. The reactivity of peanut (Arachis hypogaea) to Mn toxicity stress was examined in this study. Mn oxidation spots developed on peanut leaves, and the root growth was inhibited under Mn toxicity stress. The physiological results revealed that under Mn toxicity stress, the activities of antioxidases and the content of proline in roots and leaves were greatly elevated, whereas the content of soluble protein decreased. In addition, manganese and iron ion content in roots and leaves increased significantly, but magnesium ion content decreased drastically. The differentially expressed genes (DEGs) in peanut roots and leaves in response to Mn toxicity were subsequently identified using genome-wide transcriptome analysis. Transcriptomic profiling results showed that 731 and 4589 DEGs were discovered individually in roots and leaves, respectively. Furthermore, only 310 DEGs were frequently adjusted and controlled in peanut roots and leaves, indicating peanut roots and leaves exhibited various toxicity responses to Mn. The results of qRT-PCR suggested that the gene expression of many DEGs in roots and leaves was inconsistent, indicating a more complex regulation of DEGs. Therefore, different regulatory mechanisms are present in peanut roots and leaves in response to Mn toxicity stress. The findings of this study can serve as a starting point for further research into the molecular mechanism of important functional genes in peanut roots and leaves that regulate peanut tolerance to Mn poisoning.
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Nicolai, Merle M., Ann-Kathrin Weishaupt, Jessica Baesler, Vanessa Brinkmann, Anna Wellenberg, Nicola Winkelbeiner, Anna Gremme, et al. "Effects of Manganese on Genomic Integrity in the Multicellular Model Organism Caenorhabditis elegans." International Journal of Molecular Sciences 22, no. 20 (October 9, 2021): 10905. http://dx.doi.org/10.3390/ijms222010905.
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Although manganese (Mn) is an essential trace element, overexposure is associated with Mn-induced toxicity and neurological dysfunction. Even though Mn-induced oxidative stress is discussed extensively, neither the underlying mechanisms of the potential consequences of Mn-induced oxidative stress on DNA damage and DNA repair, nor the possibly resulting toxicity are characterized yet. In this study, we use the model organism Caenorhabditis elegans to investigate the mode of action of Mn toxicity, focusing on genomic integrity by means of DNA damage and DNA damage response. Experiments were conducted to analyze Mn bioavailability, lethality, and induction of DNA damage. Different deletion mutant strains were then used to investigate the role of base excision repair (BER) and dePARylation (DNA damage response) proteins in Mn-induced toxicity. The results indicate a dose- and time-dependent uptake of Mn, resulting in increased lethality. Excessive exposure to Mn decreases genomic integrity and activates BER. Altogether, this study characterizes the consequences of Mn exposure on genomic integrity and therefore broadens the molecular understanding of pathways underlying Mn-induced toxicity. Additionally, studying the basal poly(ADP-ribosylation) (PARylation) of worms lacking poly(ADP-ribose) glycohydrolase (PARG) parg-1 or parg-2 (two orthologue of PARG), indicates that parg-1 accounts for most of the glycohydrolase activity in worms.
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Li, Jifu, Yidan Jia, Rongshu Dong, Rui Huang, Pandao Liu, Xinyong Li, Zhiyong Wang, Guodao Liu, and Zhijian Chen. "Advances in the Mechanisms of Plant Tolerance to Manganese Toxicity." International Journal of Molecular Sciences 20, no. 20 (October 14, 2019): 5096. http://dx.doi.org/10.3390/ijms20205096.
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Manganese (Mn) is an essential element for plant growth due to its participation in a series of physiological and metabolic processes. Mn is also considered a heavy metal that causes phytotoxicity when present in excess, disrupting photosynthesis and enzyme activity in plants. Thus, Mn toxicity is a major constraint limiting plant growth and production, especially in acid soils. To cope with Mn toxicity, plants have evolved a wide range of adaptive strategies to improve their growth under this stress. Mn tolerance mechanisms include activation of the antioxidant system, regulation of Mn uptake and homeostasis, and compartmentalization of Mn into subcellular compartments (e.g., vacuoles, endoplasmic reticulum, Golgi apparatus, and cell walls). In this regard, numerous genes are involved in specific pathways controlling Mn detoxification. Here, we summarize the recent advances in the mechanisms of Mn toxicity tolerance in plants and highlight the roles of genes responsible for Mn uptake, translocation, and distribution, contributing to Mn detoxification. We hope this review will provide a comprehensive understanding of the adaptive strategies of plants to Mn toxicity through gene regulation, which will aid in breeding crop varieties with Mn tolerance via genetic improvement approaches, enhancing the yield and quality of crops.
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Crawford, T. W., J. L. Stroehlein, and R. O. Kuehl. "Manganese and Rates of Growth and Mineral Accumulation in Cucumber." Journal of the American Society for Horticultural Science 114, no. 2 (March 1989): 300–306. http://dx.doi.org/10.21273/jashs.114.2.300.
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Abstract ‘Sumter’ cucumber (Cucumis sativus L.) plants were grown in the vegetative state with nutritionally sufficient solution followed by a 2-week period with Mn deficiency (no Mn), sufficiency (0.1 mg Mn/liter), or toxicity (10 mg Mn/liter). Beginning 34 days after germination, or about 2 weeks before imposition of Mn deficiency and toxicity treatments, plants were harvested every 3 days. With Mn deficiency and toxicity, rates of accumulation of dry weight (DW), fresh weight (FW), N, P, and K were lower than with Mn sufficiency. In contrast, rates of accumulation for Cu, Fe, and Zn were generally higher with Mn deficiency, compared to these fluxes in Mn-sufficient plants. Anomalously high accumulation rates for DW, FW, Cu, and Mn were estimated for the 3-day period following the beginning of the toxic Mn treatment.
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Pak, Chun-Ho, and Chiwon W. Lee. "MICRONUTRIENT TOXICITY IN PETUNIA HYBRIDA." HortScience 27, no. 6 (June 1992): 687e—687. http://dx.doi.org/10.21273/hortsci.27.6.687e.
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Foliar micronutrient toxicity symptoms of Petunia hybrida `Ultra Crimson Star' were induced by elevated levels (from 0.25 to 6 mM) of boron (B), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo) and zinc (Zn) in the nutrient solution. Foliar toxicity symptoms of most micronutrients (except Fe) were characterized by leaf yellowing, interveinal chlorosis, and marginal necrosis. Mo toxicity was most severe. Leaf abnormality was not induced by Fe in the concentration range tested. Visible foliar toxicity symptoms developed when nutrient solution contained 5.4, 32, 28, 24, and 16 mg· liter-1, respectively, of B, Cu, Mn, Mo and Zn. Biomass yield was reduced when the fertilizer solution contained (in mg· liter-1): 22 B, 64 Cu, 335 Fe, 28 Mn, 24 Mo, and 33 Zn.
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Elamin, Osman M., and Gerald E. Wilcox. "Effect of Magnesium and Manganese Nutrition on Watermelon Growth and Manganese Toxicity." Journal of the American Society for Horticultural Science 111, no. 4 (July 1986): 588–93. http://dx.doi.org/10.21273/jashs.111.4.588.
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Abstract Watermelon [Citrullus lanatus (Thunb.) ‘Sugar Baby’ was grown in sand culture to evaluate Mn uptake as affected by solution concentration of Mn and Mg. Manganese toxicity symptoms were developed first on the lower mature leaves as small, distinct, blackish-brown speckling on the lower leaf surface that progressed to extensive vein browning and necrotic lesions. Leaves developed toxicity symptoms when they contained ≥1325 mg·liter−1 Mn. Growth was reduced at Mn concentrations in nutrient solution ≥22.5 mg·liter−1. Development of Mn toxicity symptoms was delayed with increasing Mg concentrations in solutions. Increasing Mg concentration in solution to 48 or 96 mg·liter-1 reduced Mn composition and Mg uptake per unit root surface at 2 and 30 mg·liter-1 Mn in solution, but had no effect at 60 mg·liter-1 Mn in solution.
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Thompson, Khristy J., Jennifer Hein, Andrew Baez, Jose Carlo Sosa, and Marianne Wessling-Resnick. "Manganese transport and toxicity in polarized WIF-B hepatocytes." American Journal of Physiology-Gastrointestinal and Liver Physiology 315, no. 3 (September 1, 2018): G351—G363. http://dx.doi.org/10.1152/ajpgi.00103.2018.
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Manganese (Mn) toxicity arises from nutritional problems, community and occupational exposures, and genetic risks. Mn blood levels are controlled by hepatobiliary clearance. The goals of this study were to determine the cellular distribution of Mn transporters in polarized hepatocytes, to establish an in vitro assay for hepatocyte Mn efflux, and to examine possible roles the Mn transporters would play in metal import and export. For these experiments, hepatocytoma WIF-B cells were grown for 12–14 days to achieve maximal polarity. Immunoblots showed that Mn transporters ZIP8, ZnT10, ferroportin (Fpn), and ZIP14 were present. Indirect immunofluorescence microscopy localized Fpn and ZIP14 to WIF-B cell basolateral domains whereas ZnT10 and ZIP8 associated with intracellular vesicular compartments. ZIP8-positive structures were distributed uniformly throughout the cytoplasm, but ZnT10-positive vesicles were adjacent to apical bile compartments. WIF-B cells were sensitive to Mn toxicity, showing decreased viability after 16 h exposure to >250 μM MnCl2. However, the hepatocytes were resistant to 4-h exposures of up to 500 μM MnCl2 despite 50-fold increased Mn content. Washout experiments showed time-dependent efflux with 80% Mn released after a 4 h chase period. Hepcidin reduced levels of Fpn in WIF-B cells, clearing Fpn from the cell surface, but Mn efflux was unaffected. The secretory inhibitor, brefeldin A, did block release of Mn from WIF-B cells, suggesting vesicle fusion may be involved in export. These results point to a possible role of ZnT10 to import Mn into vesicles that subsequently fuse with the apical membrane and empty their contents into bile. NEW & NOTEWORTHY Polarized WIF-B hepatocytes express manganese (Mn) transporters ZIP8, ZnT10, ferroportin (Fpn), and ZIP14. Fpn and ZIP14 localize to basolateral domains. ZnT10-positive vesicles were adjacent to apical bile compartments, and ZIP8-positive vesicles were distributed uniformly throughout the cytoplasm. WIF-B hepatocyte Mn export was resistant to hepcidin but inhibited by brefeldin A, pointing to an efflux mechanism involving ZnT10-mediated uptake of Mn into vesicles that subsequently fuse with and empty their contents across the apical bile canalicular membrane.
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Dučić, Tanja, Jürgen Thieme, and Andrea Polle. "Phosphorus Compartmentalization on the Cellular Level of Douglas Fir Root as Affected by Mn Toxicity: A Synchrotron-Based FTIR Approach." Spectroscopy: An International Journal 27 (2012): 265–72. http://dx.doi.org/10.1155/2012/374039.
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We investigated distribution of phosphorus under manganese toxicity in different tissues of 10 μm thin-root cross-section of Douglas fir (DF) (Pseudotsuga menziesii) seedlings by using synchrotron-based Fourier transform infrared microscopy (SR-FTIR) as a chemically sensitive imaging method. Manganese is an essential micronutrient in all organisms but may become toxic when present in excess. We found previously that DF varietyglauca(DFG) and varietymenziesii(DFM) differed in phosphorus uptake, subcellular localization, transport and tissue allocation, as an effect of manganese toxicity. To address the role of P in seedling tolerance under Mn toxicity, we determined P allocation in different root tissues. In DFG, but not in DFV, the P concentration was kept at a constant level even under Mn toxicity. Earlier X-ray microanalysis showed Mn accumulation in epidermal and cortical cells of both varieties after Mn treatment, suggesting that the root endodermis was a barrier for Mn to protect the vascular system and shoot from high Mn, with possible role of P ameliorations. Here, we discuss the potential role of P in Mn compartmentalization and toxicity tolerance in two different varieties.
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St. Clair, Samuel B., and Jonathan P. Lynch. "Photosynthetic and antioxidant enzyme responses of sugar maple and red maple seedlings to excess manganese in contrasting light environments." Functional Plant Biology 31, no. 10 (2004): 1005. http://dx.doi.org/10.1071/fp04049.
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Manganese (Mn) toxicity may be a significant constraint to forest health on acidic, non-glaciated soils. We hypothesised that sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) seedlings differ in their tolerance to excess Mn, and that photosynthetic sensitivity to excess Mn is exacerbated at higher light intensities through photo-oxidative stress. To test these hypotheses, we assessed photosynthesis and antioxidant enzyme responses of sugar maple and red maple seedlings at variable Mn and light levels in a greenhouse study. In both species, high Mn treatments impaired photosynthetic function, particularly in high light conditions. Responses to Mn and light depended on the developmental stage of the leaves. All sugar maple leaves were sensitive to Mn toxicity except shaded young leaves. For red maple, only mature leaves exposed to high light were prone to Mn toxicity. Antioxidant enzyme and ФPSII / ФCO2 data suggested that photo-oxidative stress did not explain the observed photosynthetic responses to treatment variables. Our results indicate that in natural forest environments, sugar maple and red maple foliage exposed to high light intensity (outer canopy, canopy gaps) may be more prone to Mn toxicity.
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Hue, Nguyen V., and Yvonne Mai. "Manganese Toxicity in Watermelon as Affected by Lime and Compost Amended to a Hawaiian Acid Oxisol." HortScience 37, no. 4 (July 2002): 656–61. http://dx.doi.org/10.21273/hortsci.37.4.656.
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Manganese (Mn) toxicity in crops is a serious problem in Hawaii, especially Kauai and Oahu, where most soils are highly weathered. To devise a management strategy to control Mn toxicity, a greenhouse experiment was conducted on an acid (pH 4.4) Oxisol (Wahiawa series) having 15g·kg-1 total Mn. Factorial combinations of lime (0, 2.0, and 4.0 g·kg-1 CaCO3) and two composts (made from chicken manure and from sewage sludge at 0, 5, and 10 g·kg-1) were applied to the soil, which was subsequently planted to watermelon (Citrullus lanatus Thunb. `Crimson Sweet'). Our preliminary results showed that: 1) liming reduced Mn extractability and phytoavailability, but the reduction in Mn per unit increase in pH was much less than predicted by theory; 2) for good watermelon growth, soluble Mn, as extracted by the saturated paste method, should be <2.0 mg·L-1 corresponding to a soil pH >5.7; 3) unlike the saturated-paste extractable Mn, the Mehlich3-extractable Mn varied less with pH in a given soil series than between soil series; 4) effects of composts on Mn toxicity varied with compost properties, especially their Ca content and pH altering capacity; and 5) the diagnostic criteria for Mn toxicity in watermelon are tentatively proposed as: leaf Mn >1000 mg·kg-1 and leaf Ca/Mn ratio (g·g-1) <25.
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Reaney, Stephen H., Graham Bench, and Donald R. Smith. "Brain Accumulation and Toxicity of Mn(II) and Mn(III) Exposures." Toxicological Sciences 93, no. 1 (June 1, 2006): 114–24. http://dx.doi.org/10.1093/toxsci/kfl028.
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Samantaray, Sanghamitra, Gyana Ranjan Rout, and Premananda Das. "MANGANESE TOXICITY IN ECHINOCHLOA COLONA: EFFECTS OF DIVALENT MANGANESE ON GROWTH AND DEVELOPMENT." Israel Journal of Plant Sciences 45, no. 1 (May 13, 1997): 9–12. http://dx.doi.org/10.1080/07929978.1997.10676663.
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Manganese (Mn2+) toxicity is probably the second most important growth-limiting factor (after aluminum toxicity) for plants in acidic soils. The objective of our study was to determine the toxic effects of different concentrations of divalent Mn (MnCl2) on the growth of Echinochloa colona in hydroponic culture. Seed germination was not inhibited by Mn concentrations of 9.1 to 910 μM in distilled water. However, the higher Mn concentration (910 μM) in nutrient solution completely suppressed root development. Although chlorophyll content decreased with increased Mn concentrations in solution, dry weights of shoots were increased by the higher Mn treatments. These treatments also produced toxicity symptoms of leaf chlorosis and necrosis. Histological studies showed that the higher Mn concentrations caused disorganization of conductive and mesophyll tissues.
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González, Alonso, and Jonathan P. Lynch. "Subcellular and tissue Mn compartmentation in bean leaves under Mn toxicity stress." Functional Plant Biology 26, no. 8 (1999): 811. http://dx.doi.org/10.1071/pp99030.
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Non-aqueous fractionation was used to characterize subcellular and tissue Mn compartmentation of mature and immature leaves of two common bean (Phaseolus vulgaris L.) cultivars contrasting in their response to Mn toxicity. Excess Mn decreases leaf CO2 assimilation through a reduction of chlorophyll content in immature leaves with no effect detected on mature leaves. We hypothesized that differential accumulation of Mn in chloroplasts occurs at different leaf developmental stages. Chloroplasts of immature leaves accumulated at least three times as much Mn as those of mature leaves at equivalent total foliar Mn. Chlorosis was positively correlated with Mn concentration in chloroplasts from high-Mn plants (r2 = 0.96; P = 0.003) but was not correlated with Mn in unfractionated tissue (r2 = 0.026; P = 0.793) nor with Mn in the epidermis-enriched fraction (r2 = 0.33; P = 0.314). Both cultivars showed high accumulation of Mn in the vacuoles as determined by the co-localization of α-mannosidase and Mn content on a continuous density gradient. Cultivars differed significantly in Mn concentration in an epidermis-enriched fraction, with the tolerant cultivar Calima accumulating more Mn in this fraction than the sensitive cultivar ZPV-292. In both cultivars, Mn was accumulated up to 2400 µg g–1 dry weight in crystal-type structures whereas the unfractionated leaf tissue contained about 500 µg g–1 dry weight. The results demonstrate that Mn compartmentation occurs at both the tissue and the organelle level and that Mn accumulation in the epidermis-enriched fraction could contribute to Mn tolerance in common bean. The role of Mn accumulation in structures resembling oxalate crystals is discussed.
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Lee, Chi Won, Chun Ho Pak, and Jong Myung Choi. "MICRONUTRIENT TOXICITY IN SEED GERANIUM PELARGONIUM × HORTORUM BAILEY." HortScience 26, no. 6 (June 1991): 764D—764. http://dx.doi.org/10.21273/hortsci.26.6.764d.
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Micronutrient toxicity symptoms of seed geranium (Pelargonium × hortorum Bailey) `Ringo Scarlet' were experimentally induced by using 9 different concentrations of B, Cu, Fe, Mn, Mo and Zn in the fertilizer solution. Plants of 3-4 true leaf stage grown in peat-lite mix were constantly fed for 5 weeks with nutrient solutions containing 0.25, 0.5, 1, 2, 3, 4, 5, and 6 mM of each micronutrient. The control solution contained 20 uM B, 0.5 uM Cu, 10 uM Fe, 10 uM Mn, 0.5 uM Mo and 4 uM Zn. Visible foliar toxicity symptoms developed when the nutrient solution contained 2, 0.5, 5, 1, 0.25, and 0.5 mM, respectively, of B, Cu, Fe, Mn, Mo, and Zn. Reduction in dry matter yield was evident when 1 mM B, 2 mM Cu, 3 mM Fe, 2 mM Mn, 0.5 mM Mo, and 1 mM Zn were used in the fertilizer solution. Leaf chlorophyll contents decreased as Cu and Mn levels increased. Elevated levels of Fe increased tissue chlorophyll contents.
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Elamin, Osman M., and Gerald E. Wilcox. "Nitrogen Form Ratio Influence on Muskmelon Growth, Composition, and Manganese Toxicity." Journal of the American Society for Horticultural Science 111, no. 3 (May 1986): 320–22. http://dx.doi.org/10.21273/jashs.111.3.320.
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Abstract Muskmelon (Cucumis melo L.) ‘Harvest Queen’ was grown in sand culture to investigate the effects of NH4:NO3 ratios on melon growth and elemental composition. Plants grown at NH4:NO3 ratios of 98:14, 84:28, and 56:56 developed NH4 toxicity symptoms, whereas plants grown with 20 ppm Mn and NH4:NO3 ratios of 0:112, 14:98, 28:84, and 56:56 developed Mn toxicity symptoms. Increasing the proportion of NH4 in nutrient solution up to 1:1 with NO3 decreased Mn concentrations in plant tissues and alleviated Mn toxicity symptoms, whereas at NH4:NO3 ratios of 84:28 and 98:14 uptake of Mn was inhibited and never reached a concentration in the tissue that developed toxicity symptoms. Shoot and root growth was greatest when grown at the 14:98 NH4:NO3 ratio. Increasing NH4 in the solution beyond 14 ppm in the 112-ppm N mixture resulted in increasing limitation of growth. Increasing Mn concentration in the nutrient solution to 20 ppm restricted growth at NH4:NO3 ratios ≤1. However, Mn treatment did not influence the growth of plants grown at NH4:NO3 ratios >1 at 84:28 and 98:14.
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Xu, Can, Hui Yang, Chao Huang, Mingguo Lan, Zujian Zou, Fagui Zhang, and Liankai Zhang. "Interaction Mechanism of Fe, Mg and Mn in Karst Soil-Mango System." Land 12, no. 1 (January 14, 2023): 256. http://dx.doi.org/10.3390/land12010256.
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Manganese (Mn), an essential trace element for plants in which it is involved in redox reactions as a cofactor for many enzymes, represents an important factor in environmental contamination. Excess Mn can lead to toxicity conditions in natural and agricultural sites. Manganese toxicity is one of the most severe growth limiting factors in acid soil, which accounts for 21% of the total arable lands in China. The more significant part of Mn-toxicity is its interactions with other mineral elements, in particular with phosphorus (P), calcium (Ca) and iron (Fe). The application of P or Ca can be beneficial in the detoxification of manganese, whereas Mn seems to interfere with Fe metabolism. Manganese toxicity varies with plant species, nutrients, and the soil environment. Mango is the main economic fruit in the karst area of the subtropical region of China. The karst soil in the mango orchard is characterized by high Fe, Mn and Mg. In order to explore the interaction among Fe, Mg, and Mn in karst soil and mango systems under high Mn conditions, a typical mango orchard in the karst depression landform in Baise in southern China was selected to study the effects of Fe and Mg on the toxic expression of Mn in mango plants and the interaction mechanism of Fe-Mn-Mg in mango plants. The results show that: (1) the mango growth status is closely correlated with Fe2+ (active iron) and Mg under the same soil Mn concentration; (2) The black spots on mango leaves were mainly caused by Fe and Mn. There is a lot of Fe3+ and Mn3+ in the black spots, which accounts for more than 90% of the total; (3) In addition, the studies also showed that the Fe and Mg inhibited the expression of Mn toxicity in mango. Conclusively, the interaction effect of Fe, Mn, and Mg is an important factor that affects mango growth, which can indicate the status of the soil and plants.
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Krishnamurti, G. S. R., and P. M. Huang. "Kinetics of potassium chloride-induced Mn release from selected Mn-toxic soils of Indonesia and the United States of America." Canadian Journal of Soil Science 74, no. 1 (February 1, 1994): 39–46. http://dx.doi.org/10.4141/cjss94-005.
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The Mn release by M KCl from two Oxisols from Indonesia and one Inceptisol from Oregon, USA was studied at different temperatures (25, 35 and 45 °C) to understand the kinetics and mechanism of Mn release from these soils, which were reported to have a Mn toxicity problem. The Mn release by M KCl continued to increase with time up to at least 772 h without reaching equilibrium. The kinetics of Mn release followed a parabolic diffusion model during the 0.25–772 h reaction period. The activation energy of Mn release, calculated from the overall diffusion coefficients, varied from 34 to 47 kJ mol−1. Even after removing the exchangeable Mn from the soils with M calcium nitrate, significant amounts of Mn were released by M KCl. Data presented indicate that ionic strength effect coupled with Cl complexation was the main mechanism governing the KCl-induced Mn release. The Mn release from the soils during the initial reaction period (0.25 h) was fast and accounted for 34–39% of the total amount of Mn released during the 772 h reaction period. The significantly high Mn release during the initial 0.25 h reaction time, the high overall diffusion coefficients of Mn release, and the high values of the pre-exponential factor (calculated from the Arrhenius equation) of Mn release from Mn-toxic soils apparently contributed to the KCl-induced Mn toxicity in these soils. Key words: Potassium chloride-induced Mn toxicity, pre-exponential factor, ionic strength, complexation
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Lee, Chiwon W., Jong-Myung Choi, and Chun-Ho Pak. "Micronutrient Toxicity in Seed Geranium (Pelargonium × hortorum Bailey)." Journal of the American Society for Horticultural Science 121, no. 1 (January 1996): 77–82. http://dx.doi.org/10.21273/jashs.121.1.77.
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Seed geranium (Pelargonium × hortorum) micronutrient toxicity symptoms were induced by applying elevated levels of B, Cu, Fe, Mn, Mo, and Zn in fertilizer solution. Beginning at the 3-4 true leaf stage, seedling plants established in 11-cm (0.67-liter) pots containing peat-lite growing medium were fertilized at each irrigation for 5 weeks with solutions containing 0.25, 0.5, 1, 2, 3, 4, 5, and 6 mm plus the standard concentration of each micronutrient. The standard solution contained 20 μm B, 0.5 μm Cu, 10 μm Fe, 10 μm Mn, 0.5 μm Mo, and 4 μm Zn. All treatment solutions contained a fixed level of macronutrients. Visible foliar toxicity symptoms were produced when the nutrient solution contained 0.5 mm B, 0.5 mm Cu, 5 mm Fe, 1 mm Mn, 0.25 mm Mo, or 0.5 mm Zn. Reduction in dry matter yield was evident when 1 mm B, 2 mm Cu, 3 mm Fe, 2 mm Mn, 0.5 mm Mo, or 1 mm Zn was used in the fertilizer solution. Leaf chlorophyll contents decreased as Cu and Mn levels in the concentration range tested increased. Elevated levels of Fe increased tissue chlorophyll contents. The relationship between the nutrient solution and tissue concentrations of each of the six micronutrients was determined.
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Ribera, Alejandra E., Marjorie M. Reyes-Díaz, Miren R. Alberdi, Daniela A. Alvarez-Cortez, Zed Rengel, and María de la Luz Mora. "Photosynthetic impairment caused by manganese toxicity and associated antioxidative responses in perennial ryegrass." Crop and Pasture Science 64, no. 7 (2013): 696. http://dx.doi.org/10.1071/cp13161.
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Manganese (Mn) toxicity can induce oxidative stress and impair photosynthesis in plants. The activity of antioxidant enzymes such as superoxide dismutase (SOD) is increased in Lolium perenne (perennial ryegrass) in response to Mn toxicity (mainly in tolerant cultivars), but it remains unclear whether non-enzymatic antioxidant compounds may have a role in Mn tolerance. Seedlings of perennial ryegrass cv. Nui (Mn-sensitive) and cv. Kingston (Mn-tolerant) were grown in a greenhouse in nutrient solution at increasing Mn doses over 21 days. Even though both cultivars showed similar Mn uptake, dry weight decreases and lipid peroxidation caused by excess Mn were higher in cv. Nui than in Mn-tolerant Kingston. Maximum quantum yield of photosystem II (PSII) (Fv/Fm) declined only in cv. Nui at the highest Mn dose. Effective quantum yield (Ф PSII), electron transport rate, CO2 assimilation, and total chlorophyll concentration in leaves decreased under excess Mn, particularly in the sensitive cultivar. Interestingly, chlorophyll a/b ratio increased (indicating relatively lower concentration of light-harvesting chlorophyll proteins as an adaptive defence mechanism) with an increase in Mn supply only in cv. Kingston, which partially explained its greater Mn tolerance compared with Nui. Concentration of carotenoids was not directly associated with non-photochemical quenching values, suggesting that ryegrass did not dissipate an excess of absorbed energy under Mn toxicity by this mechanism. At increasing excess Mn, both enzymatic (SOD activity) and non-enzymatic antioxidant responses (radical scavenging ability and phenolic concentration) were enhanced, mainly in Kingston. The enhanced antioxidant response in this cultivar suggests the hypothesis of increased capacity to control Mn-triggered oxidative stress as reflected in the reduced lipid peroxidation.
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Shuhaimi-Othman, Mohammad, Nadzifah Yakub, Nur-Amalina Ramle, and Ahmad Abas. "Toxicity of Metals to a Freshwater Ostracod:Stenocypris major." Journal of Toxicology 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/136104.
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Adults of freshwater ostracodStenocypris major(Crustacea, Candonidae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed, and median lethal times (LT50) and concentrations (LC50) were calculated. LT50and LC50increased with the decrease in mean exposure concentrations and times, respectively, for all metals. LC50s for 96 hours for Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 25.2, 13.1, 1189.8, 526.2, 19743.7, 278.9, 3101.9, and 510.2 μg/L, respectively. Metals bioconcentration inS. majorincreases with exposure to increasing concentrations, and Cd was the most toxic toS. major, followed by Cu, Fe, Mn, Pb, Zn, Al, and Ni (Cd>Cu>Fe>Mn>Pb>Zn>Al>Ni). Comparison of LC50values for metals for this species with those for other freshwater crustacean reveals thatS. majoris equally or more sensitive to metals than most other tested crustacean.
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Lavres Junior, José, André Rodrigues Reis, Mônica Lanzoni Rossi, Cleusa Pereira Cabral, Neusa de Lima Nogueira, and Eurípedes Malavolta. "Changes in the ultrastructure of soybean cultivars in response to manganese supply in solution culture." Scientia Agricola 67, no. 3 (2010): 287–94. http://dx.doi.org/10.1590/s0103-90162010000300006.
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The deleterious effects of Mn stress on many species have been studied, mainly concerning biochemical, physiological and growth parameters of plants. However, there are few studies relating the anatomical and ultrastructural changes in response to manganese (Mn) nutritional disorders, This study examined the leaf ultrastructure of Mn-inefficient (IAC-15, Santa Rosa) and Mn-efficient (IAC-Foscarin 31) soybean (Glycine max L.) genotypes in response to three rates of Mn (0.5, 2 and 200 µmol L-1) in the nutrient solution. Symptoms of Mn deficiency developed 12 days after transplanting in IAC-15 and Santa Rosa, followed by IAC-Foscarin 31 on the 15th day. Only IAC-15 and Santa Rosa leaves showed symptoms of Mn toxicity. The Mn concentration in leaves ranged from 8.6 (deficiency) to 886.3 mg kg-1 d.w. (toxicity). There were no changes either in stomata length or stomata number per unit of leaf surface. Cytoplasm disorganization was observed in IAC-15 under Mn-excess. In this case, the cytoplasm was amorphous, densely stained and extensively disorganized, with increased vacuolation. Mn effects were not found in mitochondria and nucleus in any of the genotypes tested. Under all Mn concentrations, many lipid globules were observed in the IAC15 chloroplasts. There was an increase in the number of plastids as well as in the size of starch grains within IAC-Foscarin 31 chloroplasts as Mn concentration in the nutrient solution increased. Genotypes had marked differences in the ultrastructure organization, mainly in leaf chloroplasts grown under conditions of both Mn deficiency and toxicity (the most sensitive genotype was IAC-15).
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Nyarko-Danquah, Ivan, Edward Pajarillo, Alexis Digman, Karam F. A. Soliman, Michael Aschner, and Eunsook Lee. "Manganese Accumulation in the Brain via Various Transporters and Its Neurotoxicity Mechanisms." Molecules 25, no. 24 (December 12, 2020): 5880. http://dx.doi.org/10.3390/molecules25245880.
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Manganese (Mn) is an essential trace element, serving as a cofactor for several key enzymes, such as glutamine synthetase, arginase, pyruvate decarboxylase, and mitochondrial superoxide dismutase. However, its chronic overexposure can result in a neurological disorder referred to as manganism, presenting symptoms similar to those inherent to Parkinson’s disease. The pathological symptoms of Mn-induced toxicity are well-known, but the underlying mechanisms of Mn transport to the brain and cellular toxicity leading to Mn’s neurotoxicity are not completely understood. Mn’s levels in the brain are regulated by multiple transporters responsible for its uptake and efflux, and thus, dysregulation of these transporters may result in Mn accumulation in the brain, causing neurotoxicity. Its distribution and subcellular localization in the brain and associated subcellular toxicity mechanisms have also been extensively studied. This review highlights the presently known Mn transporters and their roles in Mn-induced neurotoxicity, as well as subsequent molecular and cellular dysregulation upon its intracellular uptakes, such as oxidative stress, neuroinflammation, disruption of neurotransmission, α-synuclein aggregation, and amyloidogenesis.
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Santos, Elcio Ferreira, José Mateus Kondo Santini, Amanda Pereira Paixão, Enes Furlani Júnior, José Lavres, Marcelo Campos, and André Rodrigues dos Reis. "Physiological highlights of manganese toxicity symptoms in soybean plants: Mn toxicity responses." Plant Physiology and Biochemistry 113 (April 2017): 6–19. http://dx.doi.org/10.1016/j.plaphy.2017.01.022.
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Tsan, M. F., C. Y. Lee, and J. E. White. "Interleukin 1 protects rats against oxygen toxicity." Journal of Applied Physiology 71, no. 2 (August 1, 1991): 688–97. http://dx.doi.org/10.1152/jappl.1991.71.2.688.
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We studied the effect of interleukin 1 alpha (IL-1) in the protection against O2 toxicity. Tracheal insufflation of IL-1 resulted in a dose-dependent protection against O2 toxicity. All control rats died within 3 days of O2 exposure. In contrast, 84, 71, and 20% of rats insufflated with 5, 1, and 0.2 microgram(s) IL-1 (150, 30, and 6 x 10(4) U), respectively, survived 100% O2 exposure for greater than 11 days. At 2.3 days after O2 exposure, control rats showed severe pulmonary injury, which insufflation of 5 microgram(s) IL-1 markedly attenuated. The protection against O2 toxicity was associated with a selective enhancement of pulmonary Mn-superoxide dismutase (Mn-SOD) activity in IL-1-insufflated rats. In rats insufflated with IL-1 that survived exposure to 100% O2 for 7 days, the activities of pulmonary Mn-SOD, Cu,Zn-SOD, catalase, and glutathione peroxidase were all increased. The increased pulmonary Mn-SOD activity demonstrated in IL-1-insufflated rats at 2.3 days after O2 exposure may contribute to the protection against acute O2 toxicity, and the markedly increased activities of all pulmonary antioxidant enzymes shown in rats insufflated with IL-1 that survived O2 exposure for 7 days may in part be responsible for the chronic adaptation of these rats to a 100% O2 environment.
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Faria, Jorge M. S., Dora Martins Teixeira, Ana Paula Pinto, Isabel Brito, Pedro Barrulas, and Mário Carvalho. "Aluminium, Iron and Silicon Subcellular Redistribution in Wheat Induced by Manganese Toxicity." Applied Sciences 11, no. 18 (September 19, 2021): 8745. http://dx.doi.org/10.3390/app11188745.
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Acidic soils can promote the bioavailability of Al, Mn, and Fe to toxic levels, reducing crop growth and productivity. Symptoms of metal excess/deficit are dependent on the chemical composition of the soil solution and of plant tissues. In the present study, the concentration and subcellular distribution of Al, Mn, Fe, and Si (known to alleviate metal stress) were quantified through inductively coupled plasma mass spectrometry (ICP-MS) in roots and shoots of wheat grown in acidic soils with rising levels of Mn. In control acidic soil, wheat showed high concentrations of Al, Mn, and Fe. After Mn supplementation, bioavailable Al, Fe, and Si levels increased in the soil solution, but plant uptake ratio decreased. Root Mn levels increased, while those of Al, Fe, and Si decreased. Although elements were increasingly translocated to the shoot, root Al and Fe concentrations were 10-fold higher than those in the shoot. At the highest Mn concentration supplied, Al, Fe, and Si proportions increased in the organelles, while Mn proportion increased in the vacuole. High bioavailable Mn levels disrupt metal homeostasis in wheat grown in acidic soils, influencing element subcellular distribution. Symptoms of metal toxicity result from interactions between several elements, and therefore a comprehensive chemical analysis of soil solution and plant tissues contributes to a more accurate understanding of their uptake dynamics and their agronomic implications.
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Tsan, M. F., J. E. White, P. J. Del Vecchio, and J. B. Shaffer. "IL-6 enhances TNF-alpha- and IL-1-induced increase of Mn superoxide dismutase mRNA and O2 tolerance." American Journal of Physiology-Lung Cellular and Molecular Physiology 263, no. 1 (July 1, 1992): L22—L26. http://dx.doi.org/10.1152/ajplung.1992.263.1.l22.
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Tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1), and interleukin-6 (IL-6) are multifunctional cytokines produced by a number of cells in response to endotoxin. We have previously demonstrated (M.-F. Tsan, J. E. White, T. A. Santana, and C. Y. Lee. J. Appl. Physiol. 68: 1211–1219, 1990, and M.-F. Tsan, C. Y. Lee, and J. E. White. J. Appl. Physiol. 71: 688–697, 1991) that tracheal insufflation of 5 micrograms of TNF-alpha or 1 microgram of IL-1 markedly protects rats against O2 toxicity and enhances pulmonary Mn superoxide dismutase (Mn SOD) activity. We now report that TNF-alpha and IL-1 at subprotective doses, e.g., 1 and 0.2 micrograms, respectively, act synergistically in protecting rats against O2 toxicity. Likewise, TNF-alpha and IL-1 at 0.005 microgram/ml each act synergistically in enhancing endothelial cell Mn SOD, but not Cu,Zn SOD mRNA levels. IL-6 at 5 or 10 micrograms provides no protective effect in rats against O2 toxicity and at up to 0.5 microgram/ml has no apparent effect on endothelial cell Mn or Cu,Zn SOD mRNA levels. However, IL-6 markedly enhances TNF-alpha- and IL-1-induced increases in Mn SOD mRNA levels and O2 tolerance. These results support an important role of Mn SOD in the protection against O2 toxicity.
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Liang, Qiuli, and Bing Zhou. "Copper and Manganese Induce Yeast Apoptosis via Different Pathways." Molecular Biology of the Cell 18, no. 12 (December 2007): 4741–49. http://dx.doi.org/10.1091/mbc.e07-05-0431.
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Metal ions are essential as well as toxic to the cell. The mechanism of metal-induced toxicity is not well established. Here, for the first time we studied two essential nutritional elements, copper and manganese, for their apoptotic effects in yeast Saccharomyces cerevisiae. Although beneficial at subtoxic levels, we demonstrated that at moderately toxic levels, both metals induce extensive apoptosis in yeast cells. At even higher concentrations, necrosis takes over. Furthermore, we investigated the molecular pathways mediating Cu- and Mn-mediated apoptotic action. Mitochondria-defective yeast exhibit a much reduced apoptotic marker expression and better survival under Cu and Mn stress, indicating mitochondria are involved in both Cu- and Mn-induced apoptosis. Reactive oxygen species (ROS) are generated in high amounts in Cu- but not in Mn-induced cell death, and Cu toxicity can be alleviated by overexpression of superoxide dismutase 2, suggesting ROS mediate Cu but not Mn toxicity. Yeast metacaspase Yca1p is not involved in Cu-induced apoptosis, although it plays an important role in the Mn-induced process. A genetic screen identified Cpr3p, a yeast cyclophilin D homologue, as mediating the Cu-induced apoptotic program. Cpr3p mutant seems to eliminate Cu-induced apoptosis without affecting ROS production, while leaving necrosis intact. These results may provide important insight into a detailed understanding at the molecular and cellular level of metal toxicity and metal accumulation diseases.
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Tsan, M. F., J. E. White, C. Treanor, and J. B. Shaffer. "Molecular basis for tumor necrosis factor-induced increase in pulmonary superoxide dismutase activities." American Journal of Physiology-Lung Cellular and Molecular Physiology 259, no. 6 (December 1, 1990): L506—L512. http://dx.doi.org/10.1152/ajplung.1990.259.6.l506.
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Tracheal insufflation of tumor necrosis factor (TNF) enhances pulmonary antioxidant enzyme activities and protects rats against oxygen toxicity (J. Appl. Physiol. 68: 1211–1219, 1990). We now report that tracheal insufflation of TNF selectively induced pulmonary Mn-superoxide dismutase (SOD) mRNA in normoxia- and hyperoxia-exposed rats, leading to increased amounts of Mn-SOD specific protein and enzyme activity. Tracheal insufflation of TNF had no effect on the levels of pulmonary Cu,Zn-SOD mRNA or specific protein. Hyperoxia alone also selectively induced pulmonary Mn-SOD mRNA. However, the hyperoxia-induced increase in Mn-SOD mRNA was not associated with an increase in Mn-SOD specific protein or enzyme activity. The results suggest that the increased pulmonary Mn-SOD in TNF-insufflated rats may contribute to the TNF-induced protection against oxygen toxicity.
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Doncheva, Sn, C. Poschenrieder, Zl Stoyanova, K. Georgieva, M. Velichkova, and J. Barceló. "Silicon amelioration of manganese toxicity in Mn-sensitive and Mn-tolerant maize varieties." Environmental and Experimental Botany 65, no. 2-3 (March 2009): 189–97. http://dx.doi.org/10.1016/j.envexpbot.2008.11.006.
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Steffens, D., B. W. Hütsch, T. Eschholz, T. Lošák, and S. Schubert. "Water logging may inhibit plant growth primarily by nutrient deficiency rather than nutrient toxicity." Plant, Soil and Environment 51, No. 12 (November 20, 2011): 545–52. http://dx.doi.org/10.17221/3630-pse.
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The aim of our experiments was to investigate whether nutrient deficiency or toxicity is the cause for growth inhibition of wheat and barley in waterlogged soils. Experiments using two soils (top and subsoil) differing largely in various characteristics revealed a growth inhibition of wheat and barley in the case of subsoil due to water logging, without Fe or Mn toxicity. Water culture experiments with anaerobic (N<sub>2</sub>) and aerobic aeration confirmed that oxygen deficiency did not induce nutrient toxicity (Fe, Mn) but caused sub-optimum nutrient supply (N, P, K, Mn, Cu, Zn) of wheat and barley plants. In a split-root water culture experiment with barley, cultivating half of the root system in varying combinations of aerobic/anaerobic and with/without K supply, it was shown that sufficient K uptake occurred only when K and oxygen were applied in the same root compartment. We suggest that due to O<sub>2</sub> deficiency in the root medium, synthesis of ATP may be inhibited leading thus to a decrease in nutrient uptake. Nutrient deficiency rather than toxicity appears to be the major cause for the poor plant growth in waterlogged soils.
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Amigo, Ramón, Ana María Méndez-Espinoza, Andrés R. Schwember, Jorge Cornejo, Ricardo Baettig, and Ricardo A. Cabeza. "Management of Iron and Manganese Toxicities of Lentil Crops Grown in Central Chile." Agronomy 11, no. 10 (October 13, 2021): 2051. http://dx.doi.org/10.3390/agronomy11102051.
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Iron (Fe) and manganese (Mn) toxicity is a widespread problem in lentil production in the coastal dryland of Chile. Increasing the soil pH by liming with CaCO3 or incrementing grain yields through nitrogen fertilization can help the plants to reduce metal concentration. Thus, the main objective of this work was to evaluate two different fertilization strategies (lime (CaCO3) and nitrogen (N) additions) to reduce Fe and Mn toxicities in lentils. Lentils grown under field conditions with the highest Fe and Mn concentrations showed toxicity symptoms, but without grain yield reductions. In a pot experiment using the same soil as in the field with toxicity symptoms, the dry matter (DM) produced at the end of the trial was higher in the plants that received N while the lowest DM production was recorded in those plants treated with lime. In particular, higher root DM sustained the growth of the N-fertilized shoots, which also positively affected the grain yields being 33% higher than the control treatment (no fertilization addition). In the plants fertilized with N, the Fe and Mn levels in the shoots were lower than the control plants and those grown in soils treated with lime, but showed higher concentrations of Fe and Mn in roots. In parallel, roots exhibited high concentrations of Fe and Mn that were 13- and 9-fold higher than in the shoots. Additionally, a significant decrease of 29% in Mn concentration in the grains of plants treated with N was reported. Overall, our results suggest that an increase in DM of lentils by the addition of N can reduce the Mn concentration on leaves to a level that is likely under the threshold that causes toxicity in plant tissues. Finally, we conclude that the increase of Fe and Mn in the roots may be connected to the reduction of these metals on leaves.
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Korcak, R. F. "Response of Blueberry Species to Excessive Manganese." Journal of the American Society for Horticultural Science 113, no. 2 (March 1988): 189–93. http://dx.doi.org/10.21273/jashs.113.2.189.
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Abstract The response of blueberries (Vaccinium spp.) to added Mn was studied in soil, solution, and sand cultures. Weekly additions of up to 0.8 mg Mn to Berryland sand soil (4.3 kg/pot) for 7 months produced the most growth in highbush blueberries, and additions of 6.4 mg Mn/week resulted in growth reductions but no visual toxicity symptoms. Solution culture- (800 ml/bottle) grown ‘Blueray’ highbush blueberries tolerated Mn additions up to 96 μg·ml−1 without significant growth reductions. Under similar conditions, a lowbush clone grew best at high added Mn and had higher foliar Mn concentrations than did ‘Blueray’, the rabbiteye cultivar ‘Tifblue’, or a selection of Vaccinium elliotti Chapman. Lowering solution Ca, Mg, and NO3 levels sharply increased foliar or stem Mn concentrations of all species. Growth of three genetically diverse hybrid blueberry progenies were not signficiantly affected by relatively high levels of applied Mn or Al when grown in sand culture. Increasing Al had a greater effect on increasing root Mn concentrations than did an increase in Mn levels. There were no visual Mn toxicity symptoms expressed in any of the three media from excessive Mn levels.
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González-Villagra, Jorge, Rocio Pino, Claudio Inostroza-Blancheteau, Paula Cartes, Alejandra Ribera-Fonseca, and Marjorie Reyes-Díaz. "Pre-Harvest MeJA Application Counteracts the Deleterious Impact of Al and Mn Toxicity in Highbush Blueberry Grown in Acid Soils." Plants 10, no. 12 (December 11, 2021): 2730. http://dx.doi.org/10.3390/plants10122730.
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Volcanic ash-derived soils are characterized by low pH (pH ≤ 5.5) with increased concentrations of aluminum (Al3+) and manganese (Mn2+), which decreases plant growth, fruit quality, and yield. Methyl jasmonate (MeJA) improves abiotic stress tolerance. Our work aimed to evaluate the application of MeJA’s impact on the growth, antioxidant defense, and fruit quality of highbush blueberry grown under Al and Mn toxicity. A field assay was conducted with four-year-old bushes of highbush blueberry cultivar Legacy under eight treatments (Control, Al (87% of Al saturation), Mn (240 mg kg−1), and Al–Mn with and without MeJA application). Physiological, biochemical, and fruit quality parameters were measured. Growth rate significantly decreased with Al (20%), Mn (45%), and Al–Mn (40%). MeJA application recovered the growth rate. Photosynthetic parameters were not affected. Antioxidant activity increased under all treatments compared with controls, being higher with MeJA application. Total phenols (TP) were decreased in plants under Al (43%) and Mn (20%) compared with controls. MeJA application increased TP in all treatments. Fruits of bushes under Al and Mn toxicity with MeJA applications exhibited an increase in fruit firmness and weight, maintaining suitable contents of soluble solids. Our results provide insights about the beneficial effect of MeJA application on growth, antioxidant properties, and fruit quality of highbush blueberry plants grown in acid soils under Al and Mn toxicity.
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Sparrow, LA, and NC Uren. "The role of manganese toxicity in crop yellowing on seasonally waterlogged and strongly acidic soils in north-eastern Victoria." Australian Journal of Experimental Agriculture 27, no. 2 (1987): 303. http://dx.doi.org/10.1071/ea9870303.
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Concentrations of exchangeable and easily reducible manganese (Mn) were measured monthly for 3 1 months in acidic soils at 6 sites used for cropping in north-eastern Victoria. Manganese concentrations in shoots of wheat (Triticum aestivum), when present, were also measured. Changes in Mn concentrations in the soils and in wheat plants were related to seasonal conditions and to the occurrence of crop yellowing, a chlorotic and stunting disorder which affects cereals grown in the region. Peaks in the concentration of exchangeable Mn occurred either when the soils were waterlogged for a prolonged period or when they were subjected to extreme heating and drying during summer. Shoot concentrations of up to 1200 mg/kg of Mn were measured for plants growing in waterlogged soils. However, in some cases concentrations less than 400 mg/kg, a concentration not considered harmful, were measured in shoots of wheat growing under waterlogged conditions but which still showed symptoms of severe chlorosis and stunting. In the absence of waterlogging, concentrations of Mn in wheat shoots were usually less than 400 mg/kg. The evidence suggests that Mn toxicity is not the primary cause of crop yellowing in north-eastern Victoria, but Mn toxicity, induced by waterlogging, probably contributes to crop yellowing when waterlogging is severe. Soil acidity did not appear to be high enough to cause Mn toxicity in the absence of waterlogging.
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Nicolai, Merle M., Marcello Pirritano, Gilles Gasparoni, Michael Aschner, Martin Simon, and Julia Bornhorst. "Manganese-Induced Toxicity in C. elegans: What Can We Learn from the Transcriptome?" International Journal of Molecular Sciences 23, no. 18 (September 15, 2022): 10748. http://dx.doi.org/10.3390/ijms231810748.
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Manganese (Mn) is an essential ubiquitous transition metal and, when occupationally or environmentally overexposed, a well-known risk factor for several neurological pathologies. However, the molecular mechanisms underlying Mn-induced neurotoxicity are largely unknown. In this study, addressing RNA-Seq analysis, bioavailability and survival assays, key pathways of transcriptional responses to Mn overexposure were investigated in the model organism Caenorhabditis elegans (C. elegans), providing insights into the Mn-induced cellular stress and damage response. Comparative transcriptome analyses identified a large number of differentially expressed genes (DEGs) in nematodes exposed to MnCl2, and functional annotation suggested oxidative nucleotide damage, unfolded protein response and innate immunity as major damage response pathways. Additionally, a time-dependent increase in the transcriptional response after MnCl2 exposure was identified by means of increased numbers of DEGs, indicating a time-dependent response and activation of the stress responses in Mn neurotoxicity. The data provided here represent a powerful transcriptomic resource in the field of Mn toxicity, and therefore, this study provides a useful basis for further planning of targeted mechanistic studies of Mn-induced neurotoxicity that are urgently needed in the face of increasing industrially caused environmental pollution with Mn.
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Shuhaimi-Othman, M., R. Nur-Amalina, and Y. Nadzifah. "Toxicity of Metals to a Freshwater Snail,Melanoides tuberculata." Scientific World Journal 2012 (2012): 1–10. http://dx.doi.org/10.1100/2012/125785.
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Adult freshwater snailsMelanoides tuberculata(Gastropod, Thiaridae) were exposed for a four-day period in laboratory conditions to a range of copper (Cu), cadmium (Cd), zinc (Zn), lead (Pb), nickel (Ni), iron (Fe), aluminium (Al), and manganese (Mn) concentrations. Mortality was assessed and median lethal times (LT50) and concentrations (LC50) were calculated. LT50and LC50increased with the decrease in mean exposure concentrations and times, respectively, for all metals. The LC50values for the 96-hour exposures to Cu, Cd, Zn, Pb, Ni, Fe, Al, and Mn were 0.14, 1.49, 3.90, 6.82, 8.46, 8.49, 68.23, and 45.59 mg L−1, respectively. Cu was the most toxic metal toM. tuberculata, followed by Cd, Zn, Pb, Ni, Fe, Mn, and Al (Cu > Cd > Zn > Pb > Ni > Fe > Mn > Al). Metals bioconcentration inM. tuberculataincreases with exposure to increasing concentrations and Cu has the highest accumulation (concentration factor) in the soft tissues. A comparison of LC50values for metals for this species with those for other freshwater gastropods reveals thatM. tuberculatais equally sensitive to metals.
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Brito, Isabel, Mário Carvalho, Luís Alho, and Michael J. Goss. "Managing arbuscular mycorrhizal fungi for bioprotection: Mn toxicity." Soil Biology and Biochemistry 68 (January 2014): 78–84. http://dx.doi.org/10.1016/j.soilbio.2013.09.018.
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Gupton, Creighton, and James Spiers. "HERITABILITY OF MANGANESE TOLERANCE IN RABBITEYE BLUEBERRY." HortScience 25, no. 9 (September 1990): 1075e—1075. http://dx.doi.org/10.21273/hortsci.25.9.1075e.
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To determine whether manganese tolerance in rabbiteye blueberry (Vaccinium ashei Reade) is heritable, a 10-parent diallel cross was produced. A 250 ppm Mn solution (200 ml/plant) was applied to a sand culture, of the progeny daily. Visual ratings (1 - dead plant - 13 - no Mn toxicity symptom) were made after 6 weeks. Shoot weight and Mn content of leaves were determined. Narrow-sense heritability estimates (h2) were 0.45±0.28 for Mn content, 0.49±0.27 for visual ratings, and 0.37± 0.21 for shoot weight. The genetic correlation between neither shoot weight nor visual rating and Mn content (0.11 and -0.15, respectively) was very high; however, the correlation between shoot weight and visual ratings (1.00) was extremely high. This suggests that visual ratings provide an estimate of Mn effects on plans equal to objective measurements of shoot weight. Though h2 estimates for Mn content and visual ratings were similar, the lack of genetic correlation between the traits indicates that tolerance to Mn toxicity is independent of Mn content. The high h2 for visual ratings suggests mass selection as the method of choice for improving Mn tolerance in a rabbiteye blueberry population.
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McQuattie, Carolyn J., and George A. Schier. "Response of sugar maple (Acer saccharum) seedlings to manganese." Canadian Journal of Forest Research 30, no. 3 (March 1, 2000): 456–67. http://dx.doi.org/10.1139/x99-229.
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Long-term research in north-central Pennsylvania has revealed high levels (>2000 ppm) of foliar Mn in seedlings and overstory sugar maples (Acer saccharum Marsh.). To determine thresholds for sensitivity of sugar maple to Mn, 4-week-old seedlings growing in sand were irrigated for 8 weeks with nutrient solution (pH 3.8) containing 0.1 (control), 5, 10, 20, 40, or 80 mg Mn/L. Seedling mortality occurred at 40 (92%) and 80 (100%) mg Mn/L. At lower Mn, seedling dry mass decreased with increasing Mn concentrations; root growth was inhibited more than shoot growth. Foliar concentrations of all mineral nutrients except P were significantly reduced by Mn. Symptoms of Mn toxicity included chlorosis and necrosis in leaves, darkened root tips, and loosening of outer cortical cells in roots. Cellular symptoms observed in Mn-treated seedlings (5 mg/L and higher) included irregularities in cell shape, increased vacuolation, and swollen mitochondria in root meristems; leaves showed discrete electron-dense areas in chloroplast thylakoid membranes, increased starch in mesophyll cells, and collapse of phloem in midveins. Investigation of potential Mn toxicity will require simulated field conditions to fully evaluate interactions with other factors.
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Nogueira, Marco Antonio, and Elke Jurandy Bran Nogueira Cardoso. "Mycorrhizal effectiveness and manganese toxicity in soybean as affected by soil type and endophyte." Scientia Agricola 60, no. 2 (2003): 329–35. http://dx.doi.org/10.1590/s0103-90162003000200018.
Full textAbstract:
Mycorrhizal plants may present Mn toxicity alleviation and this depends on the plant-endophyte-environment interaction. The effectiveness of three arbuscular mycorrhizal fungi (AMF) (Glomus macrocarpum, G. etunicatum, G. intraradices) and a control without AMF in two soils: Typic Rhodudalf with high Mn availability and a Typic Quartzipsamment, with low Mn availability, was evaluated in a time-course experiment at 3, 6, 9 and 12 weeks after soybean (Glycine max L.) seedling emergence. The objective was to select the most effective AMF species to enhance plant growth and to assess its effects upon Mn uptake by plants and Mn availability in the soil. For the sandy soil, AMF inoculation resulted in increased plant biomass, especially with G. intraradices and G. etunicatum. Lower Mn concentrations were observed in shoot and root of mycorrhizal plants. For the clayey soil, there was also an increase in plant biomass, but only for plants inoculated with G. intraradices and G. etunicatum. Mycorrhizal plants presented higher Mn concentrations in shoot and root and there was an increase of available Mn in the soil, in relation to the control, especially in the treatment with G. macrocarpum. When inoculated with G. macrocarpum, plants presented Mn toxicity symptoms and reduced biomass in comparison to control plants. The effects of mycorrhizal inoculation, either positive or negative, were most intense at 9 and 12 weeks.
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Marco, DGDe, CB Li, PJ Randall, and Marco DG De. "Manganese toxicity in Trifolium balansae, T. resupinatum, T. subterraneum, Medicago murex, M. polymorpha, M. sativa, Lotus pedunculatus, and Ornithopus compressus: relative tolerance and critical toxicity concentrations." Australian Journal of Experimental Agriculture 35, no. 3 (1995): 367. http://dx.doi.org/10.1071/ea9950367.
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This paper describes the tolerance to high concentrations of manganese (Mn) of pasture legumes that are suitable for the >500 mm rainfall zone in southern Australia. The legumes are lucerne (Medicago sativa), burr medic (M. polymorpha), murex medic (M. murex), balansa clover (Trifolium balansae), Persian clover (T. resupinatum), subterranean clover (T: subterraneum), greater lotus (Lotus pedunculatus), and seradella (Ornithopus compressus). Wheat (Triticum aestivum) cv. Egret and subterranean clover cvv. Mt Barker and Karridale were included to place the tolerance of the remaining species in the context of other studies.Symptoms of toxicity differed between species. Species ranking (in descending order) for Mn tolerance, and external threshold Mn concentrations (mmol/L), were subterranean clover (1.0), wheat (0.71), balansa clover (0.54), greater lotus (0.51), serradella (0.50), Persian clover (0.25), murex medic (0.24), burr medic (0.20), and lucerne (0.19). Critical toxicity concentrations derived from the relationships of yields to Mn concentrations in whole shoots for each species were as follows (mg Mn/kg DW): subterranean clover (2010), balansa clover (1330), serradella (1080), greater lotus (760), wheat (570), burr medic (440), murex medic (430), Persian clover (360), lucerne (190).
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Jee, Hyo Kyung, and Jin Hee Park. "Adsorption of Mn on iron minerals and calcium compounds to reduce Mn(II) toxicity." Journal of Applied Biological Chemistry 65, no. 4 (December 31, 2022): 457–62. http://dx.doi.org/10.3839/jabc.2022.059.
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Husain, M., V. K. Khanna, A. Roy, R. Tandon, S. Pradeep, and P. K. Seth. "Platelet dopamine receptors and oxidative stress parameters as markers of manganese toxicity." Human & Experimental Toxicology 20, no. 12 (December 2001): 631–36. http://dx.doi.org/10.1191/096032701718890531.
Full textAbstract:
The present study has been undertaken to investigate whether neurotoxic effects of manganese (Mn) are reflected in platelets in rats to monitor the usefulness of platelet as peripheral model. Exposure of rats to Mn (10 or 15 mg/kg bw, i.p.) for 45 days caused a significant increase in membrane fluidity as evidenced by decrease in fluorescence polarisation in platelets (11% and 14%) and striatum (9% and 13%). These rats exhibited a significant increase in superoxide dismutase activity both in platelets (24% and 37%) and striatum (31% and 42%), respectively, in comparison to controls. Exposure of rats to Mn for 45 days (15 mg/kg bw, i.p.) caused a significant decrease in reduced glutathione content (platelets 20%, striatum 24%) and catalase activity (platelets 35%, striatum 44%) compared to control rats. Rats exposed to Mn (10 or 15 mg/ kg bw, i.p.) for 15 days exhibited a significant increase in dopamine receptors both in platelets (55% and 40%) and striatum (38% and 31%). The results suggest that exposure to Mn may alter the membrane functions and impair the anti-oxidant defense mechanism both in platelets and brain. The study also suggests that dopaminergic mechanisms are impaired following Mn exposure and such changes are reflected in platelets. Interestingly, parallel changes both in striatum and platelets, as observed in the present study, strengthen the usefulness of platelets as a peripheral neuronal model.