Active Iron Content Research Articles

Enhanced degradation of 2,4-DCP in a bicarbonate-modified Fenton with EDTA under near-neutral conditions

To address the issues of low pH requirements and low active iron content in the traditional Fenton system, bicarbonate in this study was presented in Fenton system to form HCO4− through reaction with hydrogen peroxide (HCO3––H2O2, BAP) and activated by FeⅡ-EDTA to enhance the degradation of 2,4-DCP under near-neutral conditions. 2,4-DCP can be totally degraded after 60 min of reaction at pH of approximately 6.4 under the optimal concentrations of Fe2+, NaHCO3 and EDTA-2Na of 4 mmol·L−1, 10 mmol·L−1 and 2 mmol·L−1, respectively. In addition to serving as a reactant in the reaction between bicarbonate and hydrogen peroxide to form the intermediate HCO4−, bicarbonate also functions as a pH buffer to bring the solution’s pH closer to neutral. The introduction of EDTA-2Na can effectively inhibit iron precipitation to promote maintaining the existence of Fe in dissolved form, improving the catalytic capacity of the system and reduce the dosage of Fe2+. The primary involvement of ·OH in the reaction process was validated by free radical quenching studies and EPR testing; the contributions of 1O2 and O2·− were very small.

Nutrient transport, shear strength and hydraulic characteristics of topsoils amended with mulch, compost and biosolids

Anthropogenic disturbance of soils can disrupt soil structure, diminish fertility, alter soil chemical properties, and cause erosion. Current remediation practices involve amending degraded urban topsoils lacking in organic matter and nutrition with organic amendments (OA) to enhance vegetative growth. However, the impact of OAs on water quality and structural properties at rates that meet common topsoil organic matter specifications need to be studied and understood. This study tested three commonly available OAs: shredded wood mulch, leaf-based compost, and class A Exceptional Quality stabilized sewage sludge (or biosolids) for nutrient (nitrogen and phosphorus) water quality, soil shear strength, and hydraulic properties, through two greenhouse tub studies. Findings showed that nitrogen losses to leachate were greater in the biosolids amended topsoils compared to leaf-compost, mulch amended topsoils, and control treatments. Steady-state mean total nitrogen (N) concentrations from biosolids treatment exceeded typical highway stormwater concentrations by at least 25 times. Soil total N content combined with the carbon:nitrogen ratio were identified to be the governing properties of N leaching in soils. Study soils, irrespective of the type of amendment, reduced the applied (tap) water phosphorus (P) concentration of ∼0.3 mg-P/L throughout the experiment. Contrary to the effects on N leaching, P was successfully retained by the biosolids amendment, due to the presence of greater active iron contents. A breakthrough mechanism for P was observed in leaf compost amended soil, where the effluent concentrations of P continued to increase with each rainfall application, possibly due to an saturation of soil adsorption sites. The addition of OAs also improved the strength and hydraulic properties of soils. The effective interlocking mechanisms between the soil and OA surfaces could provide soil its required strength and stability, particularly on slopes. OAs also improved soil fertility to promote turf growth. Presence of vegetative root zones can further reinforce the soil and control erosion.

Rapid correction of iron deficiency in peach trees by direct injection of ferrous sulfate into the trunk

ABSTRACT Chlorosis caused by iron deficiency restricts the growth of plants on calcareous and alkaline soils. The aim of this study was to evaluate the effect of different application methods of FeSO4 on iron-deficient peach trees. The experiment was conducted for 2 years as a randomized complete blocks design with seven treatments including soil application (500 g tree−1), foliar spraying (0.5% solution, 21 liters tree−1) and trunk injection of 0%, 0.5%, 1%, 1.5% and 2% solutions of FeSO4 on eight-year-old trees. The application method had a significant effect on the characteristics of fruits and leaves. Injection of FeSO4 not only led to elimination of iron chlorosis by increasing chlorophyll and active iron contents of leaves but also increased fruit weight and volume, improved fruit yield and increased TSS content of fruits as compared to the control. On the other hand, soil and foliar application treatments did not have a significant effect on fruit weight, volume and yield. Foliar application increased the active iron content of the leaves but had no significant effect on their chlorophyll content. Based on the results, trunk-injection of FeSO4 is the most effective method for eliminating iron deficiency of peach trees on calcareous and alkaline soils.

Variation of active iron and ferritin content in pear cultivars with different levels of pathogen resistance following inoculation with Erwinia amylovora

Variation of active iron and ferritin content in pear cultivars with different levels of pathogen resistance following inoculation with Erwinia amylovora

Effects of Different Irrigation Waters and Silicon Doses on Leaf SPAD Meter Readings, Chlorophyll and Carotenoid Contents of Tomato Plants

This study was conducted to determine the effects of different irrigation water treatments and silicon doses on leaf SPAD meter readings, chlorophyll content and carotenoid contents of tomato plants. Tybiff Aq tomato seedling were grown in 3-liter pots filled with 1100 g of 1:1 peat-perlite mixture for 70 days. Four different type of irrigation waters were prepared with the use of sea and tap water. Irrigation waters included I) Full sea water, II) ½ sea water + ½ tap water, III) ¼ sea water + ¾ tap water, IV) Full tap water (control). Each irrigation water was supplemented with silica gel (SiO2.xH2O) at 0, 0.5, 1 and 2 mM Si doses. Nutrient solutions were supplied to meet macro and micronutrient requirements of tomato plants. Leaf chlorophyll-a, chlorophyll-b and total chlorophyll contents significantly increased with increasing tap water ratios of the irrigation water. Significant increases were observed in chlorophyll-a, chlorophyll-b and total chlorophyll contents with increasing silicon doses. Such increases achieved with silicon treatments were more remarkable for chlorophyll-a and total chlorophyll contents. Leaf chlorophyll-a, chlorophyll-b and total chlorophyll contents significantly decreased with increasing leaf sodium, chlorine and magnesium contents, but significantly increased with increasing leaf active iron and potassium contents. Leaf chlorophyll-a, chlorophyll-b and total chlorophyll contents increased with increasing leaf calcium contents, but such increases were not significant. Leaf carotenoid contents significantly increased with increasing tap water ratios of the irrigation water. Effects of silicon doses on leaf carotenoid contents varied with the type of irrigation water. The 0.5 mM silicon supplementation into tap water significantly increased carotenoid contents.

Differential response of groundnut genotypes for iron (Fe) deficiency chlorosis tolerance and productivity traits under Fe-supplemented and Fe-non-supplemented conditions

Groundnut is sensitive to Fe deficiency under alkaline and calcareous soils and exhibits iron deficiency chlorosis (IDC) causing significant reduction in growth and yield. Genotypes were assessed for IDC related traits such as visual chlorosis rating, SPAD chlorophyll meter reading, chlorophyll and active iron (Fe2+) content across five growth stages and also for productivity traits viz., plant height, number of primary branches, number of pods per plant, pod yield, shelling per cent, 100 seed weight and haulm yield. Comparison between Fe-supplemented and Fe-nonsupplemented condition for IDC related traits showed not much difference among IDC tolerant genotypes across all five growth stages, while significant differences among IDC susceptible genotypes were observed. Maximum reduction in pod yield was observed among IDC susceptible genotypes compared to IDC tolerant and moderately tolerant genotypes. However, recently released variety G 2- 52 with moderate tolerance to IDC and higher yield potential recorded higher pod yield both under Fe applied (1754 kgha–1) and non-applied conditions (1544 kgha–1).

Effect of integrated nitrogen management and foliar spray of iron on groundnut yield, quality and economics in arid region

Aim: This experiment was conducted to find out appropriate technical intervention for integrated management of nitrogen and iron chlorosis in irrigated groundnut in arid regions. Methodology: Two levels of farmyard manure, five levels of nitrogen and three levels of iron spray were applied in irrigated groundnut. Chlorophyll content, active iron content, periodic dry matter accumulation, oil content and yield, protein content and nutrient uptake by groundnut were studied. Most effective level of farmyard manure, nitrogen application and iron spray were identified for optimum management of the resources.? Results: The results showed that application of farmyard manure @ 15 t ha-1, nitrogen @ 60 kg ha-1 in two or three splits and foliar spray of FeSO4 @ 1.0 % in combination with citric acid @ 0.1% was found supportive in correcting iron chlorosis by increasing chlorophyll and active iron content, improving oil content and yield, protein content and nutrient uptake and ultimately enhancing net return by groundnut under irrigated conditions. Interpretation: Farmyard manure, higher dose of nitrogen in split application and foliar spray of iron is helpful in correcting iron chlorosis, improving growth, quality and nutrient uptake and increasing income of groundnut growers under irrigated condition in arid regions.

Nitrogen, water content, phosphorus and active iron jointly regulate soil organic carbon in tropical acid red soil forest

AbstractIncreasing forest soil organic carbon (SOC) storage is important for reducing carbon dioxide (CO2) emissions from terrestrial ecosystems and mitigating global climate change. Although the effects of altitude, temperature and rainfall on organic carbon have been studied extensively, it is difficult to increase SOC storage by changing these factors in actual forest management. This study determined the SOC, soil physical and chemical properties, nutrient elements, heavy metal elements, soil minerals and microbial biomass in the 0–140‐cm soil layer of the monsoon broad‐leaved forest in the acid red soil region of southwestern China by stratification. We tried to identify the soil factors affecting the SOC storage of the forest in the acid red soil region and determine the weights of the factors affecting the SOC, with the aim of improving the SOC retention capacity in forest management by changing the main soil factors affecting SOC storage. The results showed that the soil factors affecting the forest SOC storage in this area are total nitrogen (N, 22.7%) > soil water content (19.9%) > active iron (including poorly crystalline iron, Feo, 15.5%) > pH (9.5%) > phosphorus (P, 9.4%) > aluminium (Al, 8.9%) > silicon (Si, 7.1%) > sulphur (S, 6.8%). Of these factors, N, the water content, Feo, and P are practical factors for forest management, whereas the pH, Al, Si and S are not. SOC was significantly positively correlated with the soil N concentration, water content, active iron content and P concentration (p < .05). In acidic red soil areas, with active iron as the highlight, N, soil water content, phosphorus and active iron jointly regulate the forest SOC storage capacity. Consequently, in actual forest management, any measures to promote soil N and water content and to activate inactive iron can enhance the storage of SOC, as appropriate input of N and P fertiliser and irrigation in dry years and the dry season.Highlights The soil environmental factors affecting SOC storage in forest soil are quantified Activation of inactive iron helps SOC storage in forest soil Irrigation and N and P input are effective for helping SOC storage in forest soil N, WC, P and Feo jointly regulate SOC in tropical acid red soil forest

Promotion of iron nutrition and growth on peanut by Paenibacillus illinoisensis and Bacillus sp. strains in calcareous soil.

This study aimed to explore the effects of two siderophore-producing bacterial strains on iron absorption and plant growth of peanut in calcareous soil. Two siderophore-producing bacterial strains, namely, YZ29 and DZ13, isolated from the rhizosphere soil of peanut, were identified as Paenibacillus illinoisensis and Bacillus sp., respectively. In potted experiments, YZ29 and DZ13 enhanced root activity, chlorophyll and active iron content in leaves, total nitrogen, phosphorus and potassium accumulation of plants and increased the quality of peanut kernels and plant biomass over control. In the field trial, the inoculated treatments performed better than the controls, and the pod yields of the three treatments inoculated with YZ29, DZ13, and YZ29 + DZ13 (1:1) increased by 37.05%, 13.80% and 13.57%, respectively, compared with the control. Based on terminal restriction fragment length polymorphism analysis, YZ29 and DZ13 improved the bacterial community richness and species diversity of soil surrounding the peanut roots. Therefore, YZ29 and DZ13 can be used as candidate bacterial strains to relieve chlorosis of peanut and promote peanut growth. The present study is the first to explore the effect of siderophores produced by P. illinoisensis on iron absorption.

Nitric oxide signaling is involved in the response to iron deficiency in the woody plant Malus xiaojinensis

To cope with iron (Fe) deficiency, plants have evolved a wide range of adaptive responses from changes in morphology to altered physiological responses. Recent studies have demonstrated that nitric oxide (NO) is involved in the Fe-deficiency response through hormonal signaling pathways. Here, we report that NO plays a significant role in Malus xiaojinensis, an Fe-efficient woody plant. Fe deficiency triggered significant accumulation of NO in the root system, predominantly in the outer cortical and epidermal cells of the elongation zone. The NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt (cPTIO) completely arrested Fe deficiency-induced root hair formation, blocked the increase in root ferric-chelate reductase activity and in root H+ excretion, further reduced the active iron content in young leaves and roots, and prevented the upregulation of the critical Fe-related genes, FIT, MxFRO2-like, and MxIRT1. These conditions were restored under Fe deficiency by treatment with the NO donor, sodium nitroprusside (SNP). Additionally, chlorophyll content and relative expression levels of the genes chlorophyll a deoxygenase (MxCAO) and polyamine oxidase (MxPAO) were not changed significantly following Fe deficiency for 6 d; however, SNP treatment increased MxHEMA gene expression. Interestingly, the Fv/Fm ratio, the maximum quantum yield of photosystem II (PSII), decreased significantly following cPTIO treatment. We observed more severe chlorosis under Fe deficiency with cPTIO treatment for 9 d. These results strongly suggest that NO mediates a range of responses to Fe deficiency in M. xiaojinensis, from morphological changes to the regulation of physiological processes and gene expression.

Modeling the hydrochlorination reaction in a laboratory-scale fluidized bed reactor

In the manufacturing process of high purity, electronics-grade silicon, the hydrochlorination reaction step for converting silicon tetrachloride (STC) to trichlorosilane (TCS) is usually carried out in a fluidized bed reactor. However, the design and operation of industrial-scale fluidized bed reactors for the conversion of STC to TCS is currently based on ad hoc rules of thumb and operator experience rather than on reaction engineering principles. In this paper, a fluidized bed model was developed by using the Kunii–Levenspiel fluidization framework. The predictive capabilities of this model were tested on laboratory-scale experimental data from the literature. It is shown that the modified Kunii–Levenspiel model accurately predicts the no catalyst addition and copper catalyst addition experiments of the hydrochlorination fluidized bed with an average percent difference of less than 6%. By making a suitable adjustment to catalytically active iron content, the model prediction is in excellent agreement with experimental data with hydrochloric acid in the feed stream. The modified Kunii–Levenspiel model is well suited for use in scale-up calculations for an industrial reactor as all the parameters are physically reasonable and can be predicted for larger reactors.

Higher concentrations of nanoscale zero-valent iron (nZVI) in soil induced rice chlorosis due to inhibited active iron transportation

In this study, the effects of concentrations 0, 100, 250, 500, 750 and 1000 mg kg−1 of nanoscale zero-valent iron (nZVI) on germination, seedlings growth, physiology and toxicity mechanisms were investigated. The results showed that nZVI had no effect on germination, but inhibited the rice seedlings growth in higher concentrations (>500 mg kg−1 nZVI). The highest suppression rate of the length of roots and shoots reached 46.9% and 57.5%, respectively. The 1000mg kg−1 nZVI caused the highest suppression rates for chlorophyll and carotenoids, at 91.6% and 85.2%, respectively. In addition, the activity of antioxidant enzymes was altered by the translocation of nanoparticles and changes in active iron content. Visible symptoms of iron deficiency were observed at higher concentrations, at which the active iron content decreased 61.02% in the shoots, but the active iron content not decreased in roots. Interestingly, the total and available amounts of iron in the soil were not less than those in the control. Therefore, the plants iron deficiency was not caused by (i) deficiency of available iron in the soil and (ii) restraint of the absorption that plant takes in the available iron, while induced by (ⅲ) the transport of active iron from the root to the shoot was blocked. The cortex tissues were seriously damaged by nZVI which was transported from soil to the root, these were proved by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). This current study shows that the mechanism of iron deficiency in rice seedling was due to transport of active iron from the root to the shoot blocked, which was caused by the uptake of nZVI.

Biochemical basis of iron deficiency chlorosis resistance in groundnut (Arachis hypogaea L.)

A pot experiment with factorial design involving normal and calcareous soil and five genotypes with differential response to iron deficiency chlorosis (IDC) viz., ICGV 86031 and A30b (Resistant), TG 26 (moderately Resistant), TAG 24 and TMV 2 (susceptibe) were tested for various traits like VCR and SCMR, chlorophyll a, b and total chlorophyll, active iron content, specific activity of peroxidase at five different stages and also know the effect of IDC on yield and yield components. Iron deficiency chlorosis resistant genotypes recorded significantly lower VCR, higher SCMR, higher active iron content, chlorophyll a, b and total chlorophyll and peroxidase activity in leaf across all stages compared to susceptible genotypes. A strong and positive correlation was observed between peroxidase activity and leaf iron content. Yield and yield components were significantly reduced in susceptible genotypes compared to resistant genotypes.

Rhizosphere Acidification is Not Part of the Strategy I Iron Deficiency Response of Vaccinium arboreum and the Southern Highbush Blueberry

Vaccinium arboreum (VA) is a wild blueberry species that exhibits wider soil pH tolerance and greater ability for iron and nitrate uptake than cultivated Vaccinium species, including southern highbush blueberry (SHB, V. corymbosum interspecific hybrids). The ability of VA and SHB to respond to iron deficiency by rhizosphere acidification was investigated. Rooted cuttings of the VA genotype FL09-502 and SHB ‘Emerald’ were transplanted to a hydroponic system filled with complete nutrient solution. After 14 days of acclimation at 45 µm iron, plants were transferred to unbuffered nutrient solutions containing 90 or 10 µm iron. ‘Emerald’ and FL09-502 plants grown in 10 µm iron exhibited less iron uptake and lower chlorophyll, total iron, and active iron contents than plants grown in 90 µm iron. Generally, there were no species-level differences in iron or nitrate uptake. Neither FL09-502 nor ‘Emerald’ acidified the rhizosphere in either the nutrient solution or in a gel-based assay, regardless of external iron concentration. A screen of 18 additional genotypes of VA and SHB confirmed that this response is absent in these taxa. Thus, rhizosphere acidification is not part of the iron deficiency response of SHB and VA. In addition, the ability to acidify the soil is not likely to be responsible for the wider soil pH tolerance of VA.

Leaf Chlorophyll Meter Readings as an Indicator for Sugarcane Yield Under Iron Deficient Typic Haplustert

The objective of this study was to assess the feasibility of using a chlorophyll meter for estimating leaf chlorophyll content of sugarcane varieties under iron deficient condition. The SPAD chlorophyll meter readings were used to measure the leaf greenness. Leaf chlorophyll contents were also determined using the acetone extraction method and metabolically active iron content of leaf was analysed by 1,10-orthophenanthroline extract. SPAD readings were significantly correlated with leaf chlorophyll content, active iron content, cane yield, sugar yield and NMC of sugarcane varieties. These results suggest that the readings from a SPAD meter can be used for rapid and non-destructive estimation of leaf chlorophyll and it could facilitate in situ decision making for identifying tolerant varieties to iron deficiency for superior sugarcane yield.

The prediction of iron contents in orchards using VNIR spectroscopy

This study investigated the possibility of determining iron deficiency in orchard leaves using visible/near-infrared methods. Sampling was performed in 24 different healthy orchards (apple, cherry, and peach trees) grouped depending on the severity of iron deficiency. The study was conducted on a total of 120 plant samples including 40 apple, 40 cherry, and 40 peach trees. Spectral reflectance of leaves was measured with a FieldSpec HandHeld spectroradiometer (ASD Inc.) using a plant probe and a leaf clip. Total and active iron contents of leaves in the same samples were determined. Derivative graphs were drawn for the measured spectral curves. Stepwise multiple linear regression analysis was used to model the total and active iron levels selected from spectral reflectance values and derivative curves. Mathematical estimation models with the highest relationship were established. Wavelengths between 540 nm and 560 nm (visible green) and 990 nm and 1010 nm (near infrared) were found to indicate the active iron levels in apple, cherry, and peach trees. The coefficients of accuracy for active iron content were found to be as follows: apple 76.70%, cherry 75.28%, and peach 78.69%. The total iron content was found to be as follows: cherry 63.25%, peach 59.65%, and apple 75.08%. The selected wavelengths produced higher estimation values for the determination of active iron than those for total iron because total iron content affected different regions of the electromagnetic spectrum.

Uptake and Distribution of Iron from Different Iron Sources Applied as Foliar Sprays to Chlorotic Leaves of Low-Chill Peach Cultivars

A greenhouse experiment was carried out to examine the uptake and distribution pattern of iron applied through different iron sources to chlorotic leaves of three low-chill peach cultivars viz. Saharanpur Prabhat, Shan-e-Punjab, and Pratap. The plants were grown in sandy loam soil containing 30 g CaCO3 kg−1 soil in plastic pots. Upon the onset of iron deficiency symptoms, separate foliar spray treatments were given using Fe-sulfate [0.5 % (w/v) and 1.0 % (w/v)], Fe-citrate [0.5 % (w/v) and 1.0 % (w/v)], and Fe-EDTA [0.1 % (w/v) and 0.2 % (w/v)] in addition to the control which received foliar spray of only distilled water. All the spray solutions except distilled water were radiolabeled with 59FeCl3. Seven days after imposition of the treatments, iron uptake and distribution was monitored. Among Fe sources, the highest Fe uptake and its distribution in the leaves were recorded with Fe-sulfate followed by Fe-citrate and FeEDTA. Among the low-chill peach cultivars, the highest Fe uptake and distribution was observed with 1.0 % (w/v) Fe-sulfate in Saharanpur Prabhat followed by Shan-e-Punjab and Pratap. The least uptake and distribution of Fe was recorded with 0.1 % (w/v) FeEDTA as iron source in the cultivar Pratap. The highest increase in physiologically active iron (Fe2+) content as well as total iron content of the leaves was also observed with the application of 1.0 % (w/v) Fe-sulfate. However, the level of physiologically active (Fe2+) iron content with 1.0 % (w/v) Fe-sulfate was found to be statistically similar the application of 0.5 % (w/v) Fe-sulfate. The leaf penetration capacity of iron and subsequent distribution of iron from different iron sources in different low-chill peach cultivars were found in the following order Fe-sulfate > Fe-citrate > Fe-EDTA.

Soil color analysis for statistically estimating total carbon, total nitrogen and active iron contents in Japanese agricultural soils

Soil color originates mainly from organic matter, iron mineralogy and moisture content. We aimed to find a suitable method to measure soil color sensitively and to evaluate the extent to which the color parameters can be useful for statistically estimating total carbon (C), total nitrogen (N) and active iron (Fe) contents in Japanese agricultural soils. A soil color reader (SPAD-503) was applied to two sample sets: (1) 100 surface soils collected throughout a 0.5-ha paddy field (field scale) and (2) 147 surface soils collected from agricultural fields in Japan (national scale). For analysis with this instrument, about 2 g of air-dried, finely-ground samples were packed firmly in a plastic cell, and their colors as they appeared on windows in both sides of the cell were measured. A CIE 1976 (L*, a*, b*) color space was used for color description. For the field-scale samples, the values of the coefficient of variation were around 15% for total C, total N and acid oxalate extractable iron (Feo). The L* value (lightness) was negatively correlated with the content of total C and total N (R2 = 0.18** and 0.26**, respectively), and the b* value (yellowness) was positively correlated with the Feo content (R2 = 0.59**). For the national-scale samples, the values of the coefficient of variation were around 60% for total C, total N and Feo. The L* value was negatively correlated with the content of total C and total N (R2 = 0.70** and 0.59**, respectively), but the b* value was not correlated with the content of Feo (R2 = 0.00). When the analysis was limited to 65 samples frequently used for paddy fields, the b* value was positively correlated with the Feo content (R2 = 0.52**). In conclusion, the proposed method enabled us to measure soil color sensitively with a small sample size. The L* and b* values obtained can be useful for rapid estimation of total C, total N and Feo contents in agricultural surface soils in Japan.

Exogenous Nitric Oxide Effects on Physiological Characteristics of a Peanut Cultivar Growing on Calcareous Soil

This study examined the effects of exogenous nitric oxide (NO) on physiological characteristics of peanut (Arachis hypogaea L.) growing on calcareous soil. Sodium nitroprusside (SNP) was added into slow-release fertilizer (SRF) or sprayed on leaves to supply NO for iron-deficient peanut. The results showed that root application of SNP at 5.63 mg/g and foliar spray of SNP at 1.0 mmol L−1 significantly enhanced the peanut growth, pod yield, and quality. The soil pH was reduced, and available iron content and iron (Fe3+) reductase activity in root were increased, indicating NO application improved the availability of iron in the soil. Additionally, NO increased the chlorophyll and active iron content in young leaves, implying NO enhanced the availability of iron within the plant. Nitric oxide also inhibited the malondialdehyde (MDA) accumulation in leaves and increased the activity of antioxidant enzymes, which protected peanut against iron-deficiency-induced oxidative stress. It was concluded that NO might be employed for ameliorating iron-deficient chlorosis of peanut on calcareous soil when added into SRF or sprayed on leaves.

EVALUATION OF DIFFERENT IRON SOURCES FOR IRON CHLOROSIS RECOVERY IN LOW-CHILL PEACH CULTIVARS

An experiment was conducted with iron chlorosis affected low-chill peach cultivars such as ‘Shaharanpur Prabhat’, ‘Shan-e-Punjab’, and ‘Pratap’ to examine the recovery upon foliar application of three iron sources namely iron (Fe)-sulfate, Fe-citrate and Fe ethylenediaminetetraacetic acid (EDTA). All the iron sources significantly increased the SPAD meter value, physiologically active (Fe2+) iron and total iron content of the leaves over control. However, highest values were noted with foliar spray of 1.0% Fe-sulfate. The low-chill peach cultivar ‘Saharanpur Prabhat’ responded best with iron resupply treatment. Significant correlations (at P ≤ 0.01) were obtained between SPAD meter readings with both physiologically active iron (Fe2+) and total iron content of leaves in all peach cultivars. Among the sources, the correlations between SPAD meter readings, physiologically active iron (Fe2+) and total iron contents were significant at P ≤ 0.01 for only Fe-sulfate and Fe-citrate. The regression analysis showed that the SPAD meter reading accounted 78.2 to 88.0% variation in physiologically active iron (Fe2+) and 65.0 to 73.7% variation in the total iron content in the low-chill peach cultivars. The SPAD readings could be used for management of iron chlorosis in peach orchard.