Symptoms Of Fe Toxicity Research Articles

The performance of grain yield and variability of ten high yielding varieties of rice at tidal swampland

Rice is the main food crop for Indonesians; hence, increasing population leads to expanding demand for this commodity. This research was carried out over potential acid sulfate soils of tidal swamplands in Matang Danau village, Sambas regency, West Kalimantan during 2018 Dry Season. The aim of the research was to evaluate grain yields and the variability of ten rice varieties. The study employed completely randomized block design with three replications. Ten rice varieties, namely Inpara 1, Inpara 2, Inpara 3, Inpara 4, Inpara 6, Inpara 8, Inpara 9, Margasari, Inpari 32 and Cillosari (as control) were investigated. The results showed that all varieties performed good phenotypic acceptabilily (score 3), without symptoms of Fe toxicity. Yielded grain ranged from 2.44 to 5.39 tons/ha in dry milled grain. The highest yield was shown by Inpari 32 (5.33 t/ha) and Inpara 1 (5.39 t/ha), suggesting that these varieties suit acid sulfate soils as an alternative to existing Cilosari cultivar.

The Effect of Straw and Purun Tikus (Eleocharis dulcis) Compost to Rice Physiological Traits, Iron Toxicity and Grain Yield on Acid Sulfate Soils

The experiment was aimed to determine the effect straw and Eleocharis dulcis compost on physiological traits and grain yield of rice grown in acid sulfate. The experiment was conducted in 2010 WS in greenhouse of ISARI, Banjarbaru. The soils was sampled from rice fields of acid sulfate soil. The experiment was employed Factorial CRD, in which first factor was three varieties and second factor were six rates straw and E. dulcis compost. Variables observated were physiological traits (root length, stomatal density, transpiration rate, total chlorophyll content, polyphenol oxidase and peroxidase activity), Fe toxicity symptoms and grain yield. The result showed that application of 5.0 t ha−1 straw and 5.0 t ha−1 E. dulcis compost resulted in the best physiological traits of rice plants, decreased Fe toxicity, but led to increase in grain yield. Inpara 1 was more tolerant to iron toxicity, better physiological traits, lower Fe toxicity symptoms, and higher grain yield compared to Inpara 2. On the other hand, IR64 was susceptible to iron toxicity and the lowest observed. Results of the experiment demonstrate that increasing rate of applied E. dulcis compost up to 5 t ha−1 may increase physiologal traits and grain yield and decrease Fe toxicity symptoms.

Variation of tolerance and accumulation to excess iron in 24 willow clones: Implications for phytoextraction

Willows (Salix spp.) are characterized by having large biomass, high tolerance to flooding, and strong metal accumulation ability, exhibiting great promise in the phytoremediation of iron (Fe) from contaminated sites. In this study, the variation of Fe tolerance and accumulation in 24 willow clones was investigated with two levels of Fe(II)-EDTA, 0.025 mM (control) and 2.0 mM (treatment) by hydroponic system for 21 days in a greenhouse. Visual symptoms of Fe toxicity were observed in the leaves and roots of Fe sensitive clones. Clonal comparisons showed a great variation in Fe tolerance, and the high levels of Fe reduced biomass productions of most clones. Tolerance indexes (TIs) varied about five-fold based on shoot dry biomass and about six-fold based on root dry biomass among clones. Clones also exhibited a wide variation in Fe concentrations (mg g–1 DW), ranged from 0.80 to 3.41 in leaves, from 5.40 to 10.51 in stems, and from 3.25 to 17.10 in roots under Fe treatments among clones. Large differences varied in the transport of Fe from roots to aerial parts among clones. The results highlighted the selection of Salix clones with high resistance to Fe toxicity and high Fe accumulation to improve phytoremediation efficacy.

Minimum Fe requirement and toxic tissue concentration of Fe in Phragmites australis: A tool for alleviating Fe-deficiency in constructed wetlands

In constructed wetlands (CWs) with forced aeration and vertical flow, plants can suffer from iron (Fe) deficiency due to Fe immobilization in the gravel substrate as a consequence of the oxic condition. The common reed (Phragmites australis) is the most commonly used plant species in CWs and frequently displays Fe-deficiency symptoms particularly in new-established systems. The aim of this study was therefore to study the Fe-nutrition of P. australis in order to gain knowledge on how Fe-deficiency in P. australis can be alleviated. For this purpose, we grew two genetically distinct phylogeographic groups of P. australis hydroponically with seven different Fe concentrations (0, 0.1, 0.2, 0.5, 1.0, 5.0 and 20.0 mg Fe-EDDHA ([iron (3+) ethylenediamine di (o-hydroxyphenylacetic) acid]) L−1) in a phytotron. Both groups responded strongly to the increasing Fe supply. The belowground biomass allocation ratio, light-saturated photosynthesis rates, chlorophyll content and leaf Fe tissue concentration all significantly increased with increasing Fe availability. Phragmites australis in the 0 mg Fe-EDDHA L−1 treatment suffered strongly from Fe deficiency, and plants in the high 20.0 mg Fe-EDDHA L−1 treatment also had reduced growth and Fe toxicity symptoms. The ‘critical deficiency concentration’ of Fe in leaves of juvenile P. australis was 40–50 mg kg−1 DM, and the ‘critical toxicity concentration’ of Fe in leaves of juvenile P. australis were approximately 150 mg kg−1 DM. Overall the two genetically distinct P. australis groups differed in their ecophysiological traits, and the two groups also responded differently to the different Fe-supply rates which may be the result of adaptations obtained in their native growth habitats. We suggest that the Fe-deficiency in CW systems with unsaturated vertical flow and/or forced aeration can be alleviated by application of a foliar spray containing chelated iron. However, the application rate and frequency should be further studied.

Genetic variation and association of molecular markers for iron toxicity tolerance in rice

Iron toxicity in rice field can cause abnormality in plant growth leading to yield loss of 35–45%. This is caused by microbial reduction under flooded conditions of insoluble iron-III (Fe 3+) into soluble iron-II (Fe2+). The severity and symptoms of Fe toxicity depends on the growth stage of rice plant at which it is exposed to the stress. The plant developed various mechanisms to avoid/tolerate such stress which is a complex phenomenon governed by multiple genes/QTLs. Very few chromosomal loci are reported for Fe toxicity resistance in rice. But no locus has been fine mapped or cloned yet. Association mapping provides opportunity to have a greater coverage of genetic diversity in various germplasm lines so that large number of loci can be identified for Fe toxicity in rice. In the present investigation, 71 genotypes including landraces and released varieties were screened for their Fe toxicity resistance ability. Various agro-morphologic traits were observed to be affected by Fe stress. The genotypes Dhusura, Jalapaya, Gelei, Kendrajhali, Rasapanjari, Saluagaja and Asinasita were observed to be resistant under field stress condition and controlled condition in hydroponic culture. These genotypes can be used as donor lines for improvement of Fe tolerance in rice. The marker-trait association study could identify the markers namely RM243, RM234, RM248, RM501, RM594 and RM517 to be associated with leaf bronzing index which is considered to be indicator of Fe toxicity resistance. These markers individually showed phenotypic variance ranging from 6.0–10.5%. These markers can further be used for marker assisted breeding programs to incorporate the Fe resistance genes/QTLs into susceptible high yielding popular varieties.

Root developmental adaptation to Fe toxicity: Mechanisms and management

ABSTRACTIron (Fe) is an essential microelement but is highly toxic when in excess. To cope with Fe excess, plants have evolved complex adaptive responses that include morphological and physiological modifications. The highly dynamic adjustments in overall root system architecture (RSA) determine root plasticity and allow plants to efficiently adapt to environmental constraints. However, the effects of Fe excess on RSA are poorly understood. Recently, we showed that excess Fe treatment in Arabidopsis not only directly impairs primary root (PR) growth but also arrests lateral root (LR) formation by acting at the tip of the growing primary root. Such a change is believed to help RSA adjust and restrict excessive Fe absorption in the part of the rhizosphere subject to acute toxicity while maintaining the absorption of other nutrients in the less stressed components of the root system. We further showed that the suppression of PR growth and LR formation under excess Fe is alleviated by K+ addition, providing useful insight into the effectiveness of nutrient management to improve RSA and alleviate Fe toxicity symptoms in the field.

Silicon Application in Cultivated Rices (Oryza sativa L and Oryza glaberrima Steud) Alleviates Iron Toxicity Symptoms Through the Reduction in Iron Concentration in the Leaf Tissue

AbstractIron (Fe) toxicity is a constraint commonly encountered in waterlogged conditions. Under anaerobic conditions, reduced Fe is massively absorbed by plants and may induce the generation of reactive oxygen species. This oxidative stress is responsible for physiological perturbations, growth reduction and yield losses. Rice is known as a silicon (Si) accumulator. Although Si is not considered as essential, it is known to play a beneficial role in the resistance to biotic and abiotic stresses through diverse and sometimes unknown mechanisms. The aim of this study was to determine the alleviation of Fe toxicity through Si application in different genotypes. Therefore, cultivars of both cultivated rice species (Oryza sativa and Oryza glaberrima) and lines from a segregating population issued from a cross between IR64 (O. sativa subsp. indica) and Azucena (O. sativa subsp. japonica) were grown in hydroponics under standard or excessive Fe(II) conditions, with or without the addition of Si. The application of Si on Fe‐treated plants strongly alleviated Fe toxicity symptoms. The reduced Fe uptake by Si‐treated plants suggested that an avoidance mechanism would be involved in this alleviation. Moreover, an additive effect of the Si and Fe treatments on the absorption of other nutrients by plants was revealed. These promising results gave insights into the understanding of rice resistance mechanisms to Fe toxicity, opening new perspectives in its management through Si fertilization. Finally, plant response to Si application was greatly influenced by the genotype. Thus, selection of stronger Si‐accumulating varieties could also be of valuable interest in the improvement of rice resistance to Fe toxicity.

Silicon nutrition potentiates the antioxidant metabolism of rice plants under iron toxicity

Iron toxicity reduces growth of rice plants in acidic lowlands. Silicon nutrition may alleviate many stresses including heavy metal toxicity in plants. In the present study, the ameliorating effects of silicon nutrition on rice (Oryza sativa L.) plants under toxic Fe levels were investigated. Plants were cultivated in greenhouse in hydroponics under different Fe treatments including 10, 50, 100, and 250 mg L−1 as Fe-EDTA and silicon nutrition including 0 and 1.5 mM sodium silicate. Iron toxicity imposed significant reduction in plant fresh weight, tiller, and leaf number. The activity of catalase, cell wall, and soluble peroxidases, and polyphenol oxidase in shoots decreased due to moderate Fe toxicity (50 and 100 mg L−1), but increased at greater Fe concentration. Ascorbate peroxidase activity increased in both roots and shoots of Fe-stressed plants. Iron toxicity led to increased tissue hydrogen peroxide and lipid peroxidation. Silicon nutrition improved plant growth under all Fe treatments and alleviated Fe toxicity symptoms, probably due to lower Fe concentration of Si-treated plants. Silicon application could improve the activity of antioxidant enzymes such as catalase, ascorbate peroxidase, and soluble peroxidase under moderate Fe toxicity, which resulted in greater hydrogen peroxide detoxification and declined lipid peroxidation. Thus, silicon nutrition could ameliorate harmful effects of Fe toxicity possibly through reduction of plant Fe concentration and improvement of antioxidant enzyme activity.

Effect of phosphorus, potassium and zinc fertilizers on iron toxicity in wetland rice ( Oryza sativa L.)

During the period January–August 1996, an investigation was carried out in La Mata, Cotui, Dominican Republic with the objective to study the effect of P, K and Zn fertilizers on Fe toxicity in the rice varieties JUMA-57 (sensitive to Fe toxicity), ISA-40 and PSQ-4 (both tolerant to Fe toxicity). The rate of fertilizer application was 22 and 62 kg P ha−1; 58 and 116 kg K ha−1; 3 and 7 kg Zn ha−1 and a constant dose of 140 kg N ha−1 and 40 kg S ha−1 on all fertilized plots. The control received no fertilizer. JUMA-57 was the only variety that showed symptoms of Fe toxicity. The observed symptoms showed a yellow to orange colour. Symptoms of Fe toxicity appeared first one week after transplanting (WAT), decreased at the fourth WAT, but returned six WAT and continued until the end of the experiment. Fertilizer application reduced symptom intensity and increased grain yield in all varieties, but only JUMA-57 did not reach the maximum yield typical for that variety. Fertilizer application did not completely overcome the toxicity effect, i.e. in symptom intensity and grain yield. The positive effect of fertilizer application could not be attributed to a specific nutrient. Intensity of symptoms was not related to Fe concentration in the leaves. The average Fe concentration of 108 mg kg−1 was not high enough to be considered toxic. Symptoms could not be explained through Mn toxicity (average Mn concentration in the leaves was 733 mg kg−1) nor Zn deficiency (average Zn concentration in the leaves was 20 mg kg−1). There was a clear relationship, though, between soil DTPA extractable Fe and symptom intensity or grain yield. The toxic effect was observed when the DTPA extractable Fe in the flooded soil was above 200 mg kg−1. From these results, we concluded that the Fe toxicity resulted from high Fe in the root zone and not from high Fe concentrations in the leaves.

Marigold Cultivars Vary in Susceptibility to Iron Toxicity

The susceptibility of seven African marigold (Tagetes erecta L.) cultivars to iron toxicity was assessed. Plants were grown in a greenhouse in a soilless medium and Fe-DTPA was incorporated into the nutrient solution at either 0.018 mmol·L-1 (low) or 0.36 mmol·L-1 (high). Symptoms of Fe toxicity (bronze speckle disorder in marigold characterized by chlorotic and necrotic speckling and downward leaf cupping and curling) developed only in the high-Fe treatment. The concentration of Fe in leaves in the high-Fe treatment was 5.6 and 1.7 times as great as in the low-Fe treatment for `Orange Jubilee' and `Discovery Orange', respectively. Based upon the percentage of plants affected and leaf symptom severity, relative cultivar susceptibility to Fe toxicity was Orange Jubilee > First Lady > Orange Lady > Yellow Galore > Gold Lady > Marvel Gold > Discovery Orange. Chemical names used: ferric diethylenetriaminepentaacetic acid, disodium salt dihydrate (Fe-DTPA).

Marigold Varieties Vary in Susceptibility to Iron Toxicity

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.

Iron and Manganese Accumulation by the brz Pea Mutant Grown in Soils

AbstractLeaf composition of the bronze (brz) mutant pea [Pisum sativum L. cv. Sparkle E107 (brz brz)] and its parent genotype (cv. Sparkle) have been compared when grown in nutrient culture, but not when grown in soil where pH has been adjusted to reduce readily available Fe and Mn. Both genotypes were grown in a growth chamber in five soils that differed in pH and DTPA‐extractable Fe and Mn. The brz genotype accumulated very high, and often toxic, concentrations of Fe and Mn when grown in acidic soils, while Sparkle did not. Liming reduced leaf‐Fe and leaf‐Mn concentrations in the brz mutant, but Fe toxicity symptoms were still evident in older leaves. In the acidic soils, leaves of the brz plants also accumulated significantly more Zn, Cu, Ca, Mg, K, Na, Al, and P than did leaves of Sparkle plants. Roots of the brz genotype depressed soil pH by several tenths of a pH unit more than did roots of Sparkle. In contrast to results obtained in the acidic and near‐neutral soils, the brz mutant and its parent grew similarly in a calcareous soil (pH 8.2), which contained low concentrations of DTPA‐extractable Fe and Mn. In conclusion, the brz mutant pea consistently accumulates high levels of Fe and Mn when these metal ions are present in readily available forms. Liming an acid soil to near‐neutral pH did not prohibit the brz mutant from accumulating potentially toxic concentrations of Fe, but growing the mutant in a calcareous soil did.

Effect of nutrients and liming on changes in pH, redox potential, and uptake of iron and manganese by wetland rice in iron-toxic soil

In a greenhouse experiment, the nutrients NPK, NPK + lime, K, and Mn were applied to an iron-toxic soil (Typic Haplastulf). Soil pH and dry matter production were increased and Eh and available Fe in the soil were decreased. Though liming the soil decreased available Fe and Mn and increased pH to the greatest extent, the highest dry matter production was obtained with NPK application. NPK + lime produced a smaller yield than NPK without lime. Though the application of K or Mn alone produced much less dry matter than NPK or NPK + lime, no symptoms of Fe toxicity were observed. We conclude that Fe toxicity can be reduced with a balanced use of fertilizers (NPK or NPK + lime) and its occurrence was mostly due to nutrient stress.

A COMPARATIVE STUDY OF THE MINERAL NUTRIENTS IN GREY AND NON-GREY FLUE-CURED TOBACCO

The macro- and micro-elemental composition of flue-cured tobacco (Nicotianum tabacum L. ’Delhi 76’) was compared in leaf and soil samples associated with non-grey (normal) plants and plants affected with the grey-tobacco disorder. Samples were collected from 15 different locations in Quebec. Chemical analyses (mean of 15 locations) indicated significantly less N, P, K, Ca, and B but more Fe and Al in grey tobacco leaves. Soils producing grey tobacco had significantly less N, Ca, organic matter, and cation exchange capacity but more Cl. The brown spotting and bronze cast symptoms on the leaves of Quebec grey tobacco plants seemed to resemble most closely symptoms of Fe toxicity. Principal component analyses showed that the mineral nutrient profiles of grey and non-grey tobacco leaf samples were clearly distinguishable, but corresponding profiles for soil samples were not.

Manganese and iron toxicities dependent on soybean variety

Abstract Tolerances to Fe and Mn were determined with Bragg and Forrest (Mn‐intolerant) and T203 and Lee (Mn‐tolerant) soybean (Glycine max. (L.). Bragg was Fe efficient; Forrest and T203 were equally Fe‐inefficient plants. The soybeans were grown in nutrient solutions with 1.0 and 2.0 mg Fe/liter, and with 0.33 and 5.1 mg Mn/liter as variables, respectively. Bragg soybeans developed Fe toxicity symptoms with 2.0, but not with 1.0 mg Fe/liter. Forrest, Lee, and T203 did not develop Fe toxicity symptoms on either treatment. Bragg and Forrest soybean developed more severe Mn‐toxicity symptoms than Lee or T203 soybean when grown on nutrient solutions with 5.1 mg Mn/liter. Approach grafts showed that Mn tolerance appears to be controlled in the plant tops. Both Mn‐intolerant and tolerant soybean tops contained about the same concentration of Mn, but Mn‐tolerant tops contained more K and roots contained less Fe than Mn‐intolerant tops and roots. When Fe and Mn toxicities are not economically correctable, toler...

Mechanism of the Differential Response of Wf9 and Oh40B Corn Seedlings to Iron Nutrition1

AbstractThe mechanism of differential response of corn (Zea muys L.) inbred lines, Oh40B and Wf9, to Fe nutrition was studied in sand and water cultures in a greenhouse. Oh40B was inefficient while Wf9 was nutritionally efficient with respect to utilization of Fe. Wf9 had a higher concentration of Fe in the tissues than Oh40B at several roncentrations of Fe in the nutrient medium, but the difference was not sufficient to account for the observed differences in chlorosis.In experiment testing the effects of Fe with other ions, Oh40B seedlings accumulated more P and Mn and showed more chlorosis than Wf9. Fe toxicity symptoms were induced in Wf9 and not in Oh40B cultured at high levels of Fe. It is concluded that Oh40B is more susceptible to chlorosis in the seedling stage than Wf9 because of its low Fe:P and Fe:Mn ratios and consequently lower amounts of available Fe. Conversely Wf9 is more prone to Fe toxicity because of its greater concentration of available Fe in the tissues, as indicated by the higher Fe:P and Fe:Mn ratios. Oh40B recovered from chlorosis at tasseling with a concomitant decrease in P and Mn concentrations.