Fe toxicity in plants: Impacts and remediation

Nitric oxide (NO) is an important bioactive signaling molecule in plants which modulates a variety of physiological processes and responses to abiotic and biotic stresses. In this study, the effects of exogenous NO supplied as sodium nitroprusside (SNP) in wheat seedlings under ironinduced oxidative damage was investigated. An appropriate concentration of NO was determined by conducting a preliminary experiment. In solution culture, wheat seeds were grown in the control (100 μM Fe), and toxic Fe (400 μM Fe) levels and the toxic Fe supply was treated with various levels of (50, 100, 200 and 500 μM) sodium nitroprusside (SNP). The results indicated that 400 μM Fe significantly decreased percentage germination, tolerance index, root lengths as well as fresh and dry weight compared to control. Exogenous SNP attenuated the inhibition of wheat seed germination. The promoting effect was most pronounced at 100 μM SNP. The accumulated concentration of iron and active Fe was significantly decreased by SNP treated Fe toxic seedlings. Toxicity of Fe caused oxidative stress by elevating hydrogen peroxide (H2O2), malondialdehyde (MDA) and proline contents in roots of wheat seedlings. One hundred μM SNP counteracted Fe toxicity by reducing the H2O2, MDA and proline contents of toxic Fe exposed seedlings. Meanwhile, application of SNP markedly reduced the activities of superoxide dismutases (SOD), catalases (CAT), peroxidase (POD), ascorbate peroxidases (APX), non protein thiols (NPT) and of glutathione reductase (GR) and increased ascorbate (ASc) compared with Fe toxic treatment alone, thereby indicating the modulation of the antioxidative capacity in the root under Fe stress by NO. The results indicated that the exogenous application of SNP, improved the antioxidant enzymes activity of wheat seedlings against Fe induced oxidative stress.

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Spatial Distribution of Trace Elements in Rice Field at Prafi District Manokwari

Indonesian Journal of Geography ◽

10.22146/ijg.12430 ◽

2016 ◽

Vol 48 (1) ◽

pp. 1

Author(s):

Aplena Elen S. Bless ◽

Samen Baan ◽

Yahya Darmawan

Keyword(s):

Trace Elements ◽

Soil Ph ◽

Metal Binding ◽

Rice Field ◽

Soil Samples ◽

Quality Information ◽

Trace Metal Concentration ◽

Measure Concentration ◽

West Papua ◽

Fe Toxicity

Mapping spatial variability of trace elements in rice Ḁeld is necessary to obtain soil quality information to en-hance rice production. ἀis study was aimed to measure concentration and distribution of Zn, Cu, Fe, Pb, and Cd in two diᴀerent sites (SP1, SP2) of PraḀ rice Ḁeld in Manokwari West Papua. ἀe representative 26 soil samples were analysed for their available trace metal concentration (DTPA), soil pH, and C-organic and soil texture. ἀe result indicated that Fe toxicity and Zn deḀcient problems were encountered in both sites. Rice Ḁeld in SP2 was more deḀcient in Zn than SP1. Site with the highest trace elements (Zn, Fe, Cu, and Cd) concentration had low soil pH and high C-organic. Acidic soil has higher solubility of metals; while high C-organic could improve the formation of dissolve organic carbon-metal binding, hence it improving the trace metals concentration in soil solution.

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Ameliorasi Berbasis Unsur Hara Silika di Lahan Rawa

Jurnal Sumberdaya Lahan ◽

10.21082/jsdl.v14n1.2020.37-47 ◽

2020 ◽

Vol 14 (1) ◽

pp. 37

Author(s):

Adha Siregar ◽

Wahida Annisa

Keyword(s):

Soil Acidity ◽

Root Zone ◽

Rice Yield ◽

Al Toxicity ◽

Rice Cultivation ◽

Limiting Factors ◽

Fe Uptake ◽

Enormous Amount ◽

Toxicity Level ◽

Fe Toxicity

Abstrak. Unsur hara Silika (Si) memiliki peranan penting pada pertumbuhan dan produktivitas tanaman padi. Tanaman padi menyerap Si dalam jumlah yang besar yaitu sekitar 10 kali N, 20 kali P, 6 kali K dan 30 kali Ca. Budidaya padi di lahan rawa memiliki beberapa faktor pembatas yang mempengaruhi pertumbuhan dan produktivitas padi diantaranya keracunan unsur toksik seperti Fe dan Al. Kadar unsur toksik terutama Fe di lahan rawa menyebabkan tanah menjadi masam, sehingga banyak tanaman yang tidak dapat beradaptasi dengan kondisi tersebut. Kondisi ini dapat diatasi diantaranya dengan aplikasi Si, yang berperan menurunkan serapan Fe dan Al yang berada dalam kondisi toksik. Beberapa hasil penelitian menunjukkan bahwa Si berpengaruh dalam menurunkan tingkat toksisitas Al dan Fe di tanah. Aplikasi Si sebagai amelioran mengurangi kandungan Fe pada permukaan akar padi serta menurunkan serapan Fe pada tanaman padi sawah melalui peningkatan kekuatan oksidasi akar. Lebih lanjut, aplikasi Si pada budidaya tanaman padi dapat meningkatkan hasil gabah sebesar 50,8%. Abtract. Silicon (Si) has an important role on rice crops growth and productivity. Rice crops absorbs enormous amount of Si as much as ten times of N, twenty times of P, six times of K and thirty times of Ca. Rice cultivation in swampland has several limiting factors such as Fe and Al toxicity. Fe toxicity could increase soil acidity in swampland. However, most plants could not adapt to this condition. Si application as soil ameliorant could be an option to overcome this problem. Si could reduce the toxicity level of Fe and Mn in soil. Previous research proved that Si could decrease Fe and Al toxicity. Si application as ameliorant could reduce Fe concentration in root zone which lead to decreasing Fe uptake through increasing oxidation capability of the root. Moreover, Si application could increase rice yield up to 50.8%..

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Root Morphology of Eight Hybrid Oil Palms Under Iron (Fe) Toxicity

Ilmu Pertanian (Agricultural Science) ◽

10.22146/ipas.11254 ◽

2016 ◽

Vol 1 (1) ◽

pp. 013

Author(s):

Aprilia Ike Nurmalasari ◽

Eka Tarwaca Susila Putra ◽

Prapto Yudono

Keyword(s):

Growth Rate ◽

Root Growth ◽

Surface Area ◽

Root Morphology ◽

Block Design ◽

Dry Weight ◽

Root Volume ◽

Oil Palms ◽

Fe Toxicity ◽

Root Growth Rate

The research aims to study the change of morphology root characters of eight hybrid oil palms under iron toxicity (Fe). Field experiment done in arranged in a Randomized Complete Block Design (RCBD) two factors and three blocks as replications. The first factor was Fe concentration. It consists of two levels which are concentration 0µ.g-1 and concentration 600 µg.g-1 Fe. The second factor is the hybrid of oil palms which consists of eight hybrid oil palms as Yangambi, Avros, Langkat, PPKS 239, Simalungun, PPKS 718, PPKS 540 and Dumpy. Fe was applied by pouring FeSO4 solvent for 600 µg.g-1 500 ml.-1plant.-1day-1 on two months of plants after transplanting in the main nursery. Data were collected on root morphology and plant dry weight The data were analysis of variance (ANOVA) at 5% significanly, followed by Duncan's multiple range test (DMRT). The relationships by among variables were determined by correlation analysis. The results showed that Fe concentration 600 µg.g-1 inhibits relatively root growth rate, narrows surface area, reduces the diameter, and shrinks root volume of all hybrid oil palms tested. The slowing relatively root growth rate, narrowing of root surface area and root diameter also root volume shrinkage due to Fe stress. It was also shown that the dry weight of plants was inhibit by existing of Fe toxicity.

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Mechanistic understanding of iron toxicity tolerance in contrasting rice varieties from Africa: 2. Root oxidation ability and oxidative stress control

Functional Plant Biology ◽

10.1071/fp19054 ◽

2020 ◽

Vol 47 (2) ◽

pp. 145

Author(s):

Dorothy A. Onyango ◽

Fredrickson Entila ◽

James Egdane ◽

Myrish Pacleb ◽

Meggy Lou Katimbang ◽

...

Keyword(s):

Oxidative Stress ◽

Sub Saharan Africa ◽

Rice Varieties ◽

Excess Iron ◽

Improvement Programs ◽

Sub Saharan ◽

Breeding Efficiency ◽

Biochemical Analyses ◽

Fe Toxicity ◽

And Control

To enhance breeding efficiency for iron (Fe) toxicity tolerance and boost lowland rice production in sub-Saharan Africa, we have characterised the morphological, physiological and biochemical responses of contrasting rice varieties to excess iron. Here, we report the capacity of four varieties (CK801 and Suakoko8 (tolerant), Supa and IR64 (sensitive)) to oxidise iron in the rhizosphere and control iron-induced oxidative stress. The experiments were conducted in hydroponic conditions using modified Magnavaca nutrient solution and 300 ppm of ferrous iron (Fe2+) supplied in the form of FeSO4. Severe oxidative stress was observed in sensitive varieties as revealed by their high levels of lipid peroxidation. Histochemical and biochemical analyses showed that tolerant varieties exhibited a better development of the aerenchyma and greater oxygen release than the sensitive varieties in response to excess Fe. Both suberin and lignin deposits were observed in the root, stem and leaf tissues but with varying intensities depending on the variety. Under iron toxic conditions, tolerant varieties displayed increased superoxide dismutase (SOD), glutathione reductase (GR), peroxidase (POX) and ascorbate peroxidase (APX) activities in both the roots and shoots, whereas sensitive varieties showed increased APX and catalase (CAT) activities in the roots. This study had revealed also that Suakoko8 mainly uses root oxidation to exclude Fe2+ from its rhizosphere, and CK801 possesses a strong reactive oxygen species scavenging system, in addition to root oxidation ability. Key traits associated with these tolerance mechanisms such as a well-developed aerenchyma, radial oxygen loss restricted to the root cap as well as strong activation of antioxidative enzymes (SOD, GR, POX and APX) could be useful selection criteria in rice varietal improvement programs for enhanced Fe toxicity tolerance.

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ATG genes, new players on early Fe toxicity response in rice ( Oryza sativa )

Plant Breeding ◽

10.1111/pbr.12860 ◽

2020 ◽

Vol 139 (6) ◽

pp. 1090-1102

Author(s):

Latóia Eduarda Maltzahn ◽

Vívian Ebeling Viana ◽

Carlos Busanello ◽

Eduardo Venske ◽

César Luis Girardi ◽

...

Keyword(s):

Oryza Sativa ◽

Toxicity Response ◽

Atg Genes ◽

Fe Toxicity

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How Does Rice Defend Against Excess Iron?: Physiological and Molecular Mechanisms

Frontiers in Plant Science ◽

10.3389/fpls.2020.01102 ◽

2020 ◽

Vol 11 ◽

Cited By ~ 1

Author(s):

May Sann Aung ◽

Hiroshi Masuda

Keyword(s):

Molecular Mechanisms ◽

Low Ph ◽

Ion Concentration ◽

Growth And Yield ◽

Association Analyses ◽

Excess Iron ◽

Fe Uptake ◽

Fe Toxicity ◽

Fe Excess ◽

Excess Fe

Iron (Fe) is an essential nutrient for all living organisms but can lead to cytotoxicity when present in excess. Fe toxicity often occurs in rice grown in submerged paddy fields with low pH, leading dramatical increases in ferrous ion concentration, disrupting cell homeostasis and impairing growth and yield. However, the underlying molecular mechanisms of Fe toxicity response and tolerance in plants are not well characterized yet. Microarray and genome-wide association analyses have shown that rice employs four defense systems to regulate Fe homeostasis under Fe excess. In defense 1, Fe excess tolerance is implemented by Fe exclusion as a result of suppression of genes involved in Fe uptake and translocation such as OsIRT1, OsYSL2, OsTOM1, OsYSL15, OsNRAMP1, OsNAS1, OsNAS2, OsNAAT1, OsDMAS1, and OsIRO2. The Fe-binding ubiquitin ligase, HRZ, is a key regulator that represses Fe uptake genes in response to Fe excess in rice. In defense 2, rice retains Fe in the root system rather than transporting it to shoots. In defense 3, rice compartmentalizes Fe in the shoot. In defense 2 and 3, the vacuolar Fe transporter OsVIT2, Fe storage protein ferritin, and the nicotinamine synthase OsNAS3 mediate the isolation or detoxification of excess Fe. In defense 4, rice detoxifies the ROS produced within the plant body in response to excess Fe. Some OsWRKY transcription factors, S-nitrosoglutathione-reductase variants, p450-family proteins, and OsNAC4, 5, and 6 are implicated in defense 4. These knowledge will facilitate the breeding of tolerant crops with increased productivity in low-pH, Fe-excess soils.

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Renal cortical hemopexin accumulation in response to acute kidney injury

AJP Renal Physiology ◽

10.1152/ajprenal.00426.2012 ◽

2012 ◽

Vol 303 (10) ◽

pp. F1460-F1472 ◽

Cited By ~ 22

Author(s):

Richard A. Zager ◽

Ali C. M. Johnson ◽

Kirsten Becker

Keyword(s):

Acute Kidney Injury ◽

Proximal Tubule ◽

Ischemia Reperfusion ◽

Kidney Injury ◽

Acute Phase Reactant ◽

Protein Accumulation ◽

Mrna Levels ◽

Hek 293 ◽

Free Heme ◽

Fe Toxicity

Hemopexin (Hpx) is a liver-generated acute phase reactant that binds and neutralizes prooxidant free heme. This study tested whether acute kidney injury (AKI) triggers renal Hpx accumulation, potentially impacting heme Fe-mediated tubular injury. Mice were subjected to glycerol, cisplatin, ischemia-reperfusion (I/R), or endotoxemic [lipopolysaccharide (LPS)] AKI. In each instance, 3- to 30-fold renal cortical and isolated proximal tubule segment (PTS) Hpx increases resulted. Although renal cortex and PTS showed variable Hpx mRNA increases, due, in part, to increased mRNA stability, mRNA levels did not correlate with renal Hpx protein accumulation. Conversely, AKI evoked three- to fourfold increases in hepatic Hpx gene induction, which corresponded with three- to fourfold plasma Hpx increases. Renal immunohistochemistry, and increased urinary Hpx excretion, indicated that circulating Hpx gains tubule luminal/urinary access, followed by proximal tubule endocytic uptake. Paradoxically, in cultured renal cells (HK-2, HEK-293), Fe depletion, and not free heme excess, increased Hpx mRNA. LPS acutely increased HK-2 cell Hpx mRNA. This finding, coupled with observations that LPS evoked ∼30-fold greater renal Hpx mRNA increases than any other AKI model, suggests that inflammation, not heme exposure, activates the renal Hpx gene. Each form of AKI evoked early increases in circulating free heme, which subsequently fell to subnormal levels as plasma Hpx rose. In addition, purified Hpx blunted free Fe-mediated HK-2 cell death. In sum, these data indicated that AKI-associated hepatic stress generates Hpx, which gains renal tubule access. Given its ability to bind free heme and mitigate free Fe toxicity, Hpx loading can potentially confer cytoprotective effects.

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Marigold Varieties Vary in Susceptibility to Iron Toxicity

HortScience ◽

10.21273/hortsci.31.4.674e ◽

1996 ◽

Vol 31 (4) ◽

pp. 674e-674

Author(s):

Joseph P. Albano ◽

William B. Miller

Keyword(s):

Plant Height ◽

Nutrient Solution ◽

Dry Weight ◽

Iron Toxicity ◽

First Lady ◽

Orange Leaf ◽

Fe Toxicity ◽

Leaf Dry Weight ◽

Dwarf Type

Our objective was to assess the susceptibility of seven marigold varieties to Fe toxicity. Marigold varieties included were one hedge type, `Orange Jubilee'; five semi-dwarf types, `First Lady', `Gold Lady', `Orange Lady', `Marvel Gold', and `Yellow Galore'; and one dwarf type, `Discovery Orange'. Plants were grown in a greenhouse in a soilless medium and treatments consisted of 0.018 mm (low) and 0.36 mm (high) Fe-DTPA incorporated into a nutrient solution. Plant height was not affected by Fe treatment and ranged from 32 cm in `Orange Jubilee', 13 to 14 cm in the semi-dwarf varieties, and 7.0 cm in `Discovery Orange'. Leaf dry weight per plant was not affected by Fe treatment and ranged from 1.15 g in `Orange Jubilee', 0.68 to 0.95 g in the semi-dwarf varieties, and 0.56 g in `Discovery Orange'. Symptoms of Fe toxicity only developed in the high Fe treatment, and the percent leaf dry weight separated at harvest as symptomatic ranged from 97% in `Orange Jubilee', 55% to 85% in the semidwarf varieties, and 15% in `Discovery Orange'. The Fe concentration in leaves in the high Fe treatment was 5.7-times greater in `Orange Jubilee', 2 to 3-times greater in the semi-dwarf varieties, and 1.6-times greater in `Discovery Orange' than in the low Fe treatment. Based on these findings, `Orange Jubilee' and `Discovery Orange' were the most and least susceptible varieties, respectively, to Fe toxicity of the seven marigold varieties evaluated in this study.

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Contribution of Eelemental Sulfur to Soil Acidification, Fe Release and Uptake by corn (Zea mays L.)

Journal of Botanical Research ◽

10.30564/jrb.v1i1.430 ◽

2019 ◽

Vol 1 (1) ◽

Author(s):

Mehdi Karimi

Keyword(s):

Zea Mays ◽

Soil Ph ◽

Soil Acidification ◽

Elemental Sulfur ◽

Zea Mays L ◽

Application Rate ◽

Unit Increase ◽

Glasshouse Experiment ◽

Fe Toxicity ◽

S Application

Abstract—A glasshouse experiment was conducted to elucidate the effectiveness of elemental sulfur as a soil acidulates on solubility of soil Fe and it’s uptake by corn (Zea mays L.). Four rates of elemental sulfur, 0, 0.5, 1 and 2 g S kg-1 soil, incubated for 0, 20 and 40 days before corn plantation. The result showed that with one unit increase in S application rate the soil pH decreased about 1.52 units and the solubility of the Fe was significantly increased. The concentration of Fe in corn leaves and stem were increased with soil acidification from the background of 7.03 to 5.42 due to elemental sulfur application rate of 1 g S kg-1 soil. However, further soil acidification decreased Fe concentration in corn. Overall, application of elemental sulfur at a rate of 0.5 g S kg-1 soil is recommended to enhance corn performance by 45 percent without the risk of Fe toxicity for corn and the minimum Fe export to groundwater.

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