Foliar Fe Application Research Articles

Role of foliar iron in modulating primary and antioxidant mechanisms of Mentha piperita L. under different light conditions

The present study aims to uncover the role of foliar iron in modulating primary and antioxidant mechanisms of Mentha piperita L. under light conditions. Plants were distributed in a completely randomized design and submitted to five Fe concentrations; 0 (control), 0.5, 1.0, 1.5 and 2.0 g L−1. And under two irradiance conditions; I100% (full sun) and I50% (50% irradiance). Forty-eight hours after foliar Fe application, the following parameters were determined: gas exchange, chlorophyll (a and b), carotenoids and anthocyanin content, chlorophyll a fluorescence, peroxidase and superoxide dismutase activities. The highest Fe concentrations affect the internal CO2 concentration (Ci) and water use efficiency, according to the photochemical extinction coefficient and peroxidase and superoxide dismutase activities. I100% increased the minimum dark-adapted leaf fluorescence and electron transport rate, while, I50% increased the chlorophyll values, and carotenoid content, Ci and transpiration, maximum dark-adapted leaf fluorescence, antenna quantum efficiency and dark-adapted fluorescence. We discovered that isolated treatments are more effective in modifying the response mechanisms of M. piperita plants and the interaction of Fe and irradiance tends to alter antioxidant metabolism.

Combined foliar application of Zn and Fe increases grain micronutrient concentrations and alleviates water stress across diverse wheat species and ploidal levels

This study aimed to examine the reaction of several wheat species with different ploidy levels to foliar application of zinc (Zn) and iron (Fe) under different water regimes. Thirty-five wheat genotypes, including nineteen tetraploids from ten different species, ten hexaploids from five species, and six diploids from three species, were evaluated in the field over two moisture regimes with the following four treatments: control, foliar Zn application, foliar Fe application, and foliar Zn + Fe application. The experiments were conducted according to a split-plot scheme in a randomized complete block design with two replications in each moisture regime. Water stress negatively affected all measured traits, except grain Zn and Fe content. Combined foliar application of Zn + Fe significantly increased yield and alleviated yield reduction caused by water stress. Applying Zn and Fe significantly increased both micronutrient content in grains under both moisture conditions. Tetra and hexaploid species yielded nearly four times as much grain as unimproved diploid species and were less affected by water stress. All ploidy levels responded almost similarly to Zn and Fe treatments, with the combined application being as effective as each element separately. The highest yield increase in response to combined application of Zn + Fe under the two moisture conditions and the highest grain Zn content in response to Zn application under water stress was observed in hexaploid wheat. Combined foliar application of Zn and Fe increases grain Zn and Fe and alleviates water stress's adverse effects on all wheat ploidy levels, making biofortification cost-effective.

Iron biofortification in quinoa: Effect of iron application methods on nutritional quality, anti-nutrient composition, and grain productivity

Biofortification of iron (Fe) in quinoa (Chenopodium quinoa) grains should have benefits for human health and food security. However, effects of this approach on productivity, as well as Fe content and grain quality remain unknown. Thus, a greenhouse experiment was conducted to determine the impacts of different methods of Fe delivery in a hydroponic system, root application (90 µmol/L), foliar spraying (9 mmol/L), combined root and foliar application, and control (no Fe). Foliar Fe application in four applications at vegetative and reproductive stages stood out from root application in promoting quinoa growth and productivity, perhaps because of greater accumulation of Fe in the plants, leading to increased photosynthetic pigments and electron transport. Foliar application of Fe also improved grain quality, as it was associated with higher Fe contents, ascorbic acid (AsA), total proteins, and manganese (Mn). In addition, there was a decrease in antinutritional compounds and phosphorus (P) in grains. Foliar Fe application can be an efficient agronomic practice to obtain Fe-biofortified quinoa grains and was associated with improved physiological responses and productivity.

Effects of Soil Aeration and Fertilization Practices on Alleviating Iron Deficiency Chlorosis in “Huangguan” Pears Grafted onto Quince A in Calcareous Soils

In North China, the high-quality pear cultivar “Huangguan” (Pyrus bretschneideri Rehd. cv), which is grafted onto dwarf quince A (Cydonia oblonga Mill. cv) rootstock and grown in calcareous soil, experiences severe iron (Fe) deficiency; this deficiency greatly constrains tree growth as well as fruit yield and quality. Therefore, we evaluated the effects of six practices for alleviating chlorosis caused by Fe deficiency in “Huangguan” grafted onto quince A (HG-QA). The practices included ridging with landscape fabric mulching as a control, flattening with landscape fabric mulching (FM), ridging without landscape fabric mulching (R), flattening without landscape fabric mulching (F), Fe fertilizer application in soil (SFe), foliar Fe application (FFe), and manure application (M). The results showed that the leaf Fe concentration increased by 356% under FFe, compared to that under the control, but the practice failed to alleviate Fe deficiency chlorosis. In contrast, an increase in leaf Fe concentration and chlorosis alleviation were observed under F. F alleviated chlorosis mainly by increasing the root ferric-chelate reductase activity. These results indicate that Fe uptake and utilization in leaves are independent biochemical processes and soil aeration improvement have positive effect on increasing Fe uptake. M improved both the soil active Fe concentration and leaf Fe utilization. Thus, manure application should be the first choice for alleviating Fe deficiency chlorosis in HG-QA grown in calcareous soils. Combining manure application with other practices that increase Fe uptake would likely be an effective way to address the problem of Fe deficiency chlorosis.

Foliar Micronutrient Application for High-Yield Maize

Nebraska soils are generally micronutrient sufficient. However, critical levels for current yields have not been validated. From 2013 to 2015, 26 on-farm paired comparison strip-trials were conducted across Nebraska to test the effect of foliar-applied micronutrients on maize (Zea mays L.) yield and foliar nutrient concentrations. Treatments were applied from V6 to V14 at sites with 10.9 to 16.4 Mg ha−1 yield. Soils ranged from silty clays to fine sands. Soil micronutrient availability and tissue concentrations were all above critical levels for deficiency. Significant grain yield increases were few. Micronutrient concentrations for leaf growth that occurred after foliar applications were increased 4 to 9 mg Zn kg−1 at 5 of 17 sites with application of 87 to 119 g Zn ha−1, 12 to 16 mg kg−1 Mn at 2 of 17 sites with application of 87 to 89 g Mn ha−1, and an average of 8.1 mg kg−1 Fe across 10 sites showing signs of Fe deficiency with application of 123 g foliar Fe ha−1. Foliar B concentration was not affected by B application. Increases in nutrient concentrations were not related to grain yield responses except for Mn (r = 0.54). The mean, significant grain yield response to 123 g foliar Fe ha−1 was 0.4 Mg ha−1 for the 10 sites with Fe deficiency symptoms. On average, maize yield response to foliar Fe application can be profitable if Fe deficiency symptoms are observed. Response to other foliar micronutrient applications is not likely to be profitable without solid evidence of a nutrient deficiency.

Application of different foliar iron fertilizers for enhancing the growth and antioxidant capacity of rice and minimizing cadmium accumulation.

Iron (Fe) fertilizer can reduce cadmium (Cd) uptake and toxicity in rice, but the underlying mechanisms of Cd mitigation by different fertilizers are poorly understood. Here, pot experiments in rice were conducted to characterize the effects of four types of foliar-applied Fe fertilizer (chelated ferrous Fe, ferric Fe, ionic ferrous Fe, and ferric Fe) at three doses (20, 50, and 100mgL-1) on photosynthetic capacity, antioxidant ability, yield, and Cd accumulation in Cd-contaminated soil. The results showed that foliar Fe application increased the net photosynthesis rate by 19.3%, peroxidase (POD) by 18.2%, superoxide dismutase (SOD) by 26.9%, and catalase (CAT) by 19.6%, and led to a 7.2% increase in grain yield compared with the control. Moreover, foliar Fe application significantly reduced Cd accumulation by 15.9% in brown rice and decreased the translocation of Cd from roots to other plant tissues. Overall, application of moderate doses (50mgL-1) of chelated ferrous Fe was the most effective method for reducing Cd uptake (decreasing the Cd concentration in brown rice by 29.0%) and toxicity in rice (decreasing malondialdehyde by 23.2% and increasing POD, SOD, and CAT by 54.4%, 51.6%, and 45.7%, respectively), which may stem from the fact that chelated ferrous Fe was a more stable and bioavailable source of Fe for rice. The Cd concentration in rice had negative relationship with Fe concentration, and the translocation of Cd from root to the other tissues was reduced by the higher Fe nutrition status in leaf, suggesting that a high Fe supply may decrease Cd content by inhibiting the expression of the Fe transport system. These results indicate that foliar application of chelated ferrous Fe provides a promising alternative approach for enhancing growth and controlling Cd accumulation in rice plants. Furthermore, these results advance our understanding of the associations between plant Fe nutrition status and Cd accumulation.

Nano- and Pheroid technologies for development of foliar iron fertilizers and iron biofortification of soybean grown in South Africa

BackgroundFoliar iron (Fe) fertilization of crops may increase Fe concentrations in edible portions of plants and improve yield in soils with low available Fe. However, the role of foliar Fe fertilization in increasing seed Fe has not been studied in soybeans (Glycine max). In this study, the Pheroid® nutrient delivery technology was combined with FeSO4 or nanostructured FePO4 to develop potential new Fe foliar fertilizers. Eight different treatments including different combinations of FeSO4 and Pheroids were foliarly applied on field-grown soybeans in Northern Cape province in South Africa to investigate their influence on seed nutrient composition and yield.ResultsConfocal and optical microscopy images indicate that FeSO4 or FePO4 was not entrapped in the Pheroids but formed separate precipitates. The average seed Fe of the non-treated plants was 56 ± 3 mg kg−1, and none of the treatments (including the positive controls, FeSO4 and FeSO4 with citrate) significantly increased seed Fe over the control. There was also no significant change in yield or seed Zn, P, protein, or phytic acid. Thus, Pheroids as well as FeSO4 are not suitable as delivery system for Fe to soybean seeds due to Pheroid incompatibility with FeSO4 and poor dispersibility of FePO4.ConclusionsBecause none of the Fe treatments (including positive controls) affected seed Fe concentrations, foliar Fe application may not be effective to increase seed Fe in crops such as soybean that already have high native Fe.

English

Animal husbandry is integral part of subsistence farming for small holder farmers but non availability of good quality fodder for feeding to the livestock is major hurdle for dairy industry in South Asia. Micronutrients such as Fe deficiency in soil affect yield and quality of forage crops severely. This study was conducted for two consecutive years (2012 and 2013) to examine the effect of foliar spray of FeSO4 on the development, herbage yield, nutritive composition and quality of teosinte grown in Fe deficient alkaline field. The experiment was conducted in Randomized Block Design with set of seven treatments viz. two foliar sprays of 0.5, 1.0 and 2.0% FeSO4 at 30, 37 DAS and three foliar sprays of 0.5, 1.0 and 2.0% FeSO4 at 30, 37 and 44 DAS. An additional treatment with recommended dose of fertilizer along with foliar spray of deionized water was kept as control. The results of this study revealed an increase of 29.6 to 32.6% in green herbage yield (GHY) and 53.3 to 60.8% in dry matter yield (DMY) with 1.0 and 2.0% foliar sprays of FeSO4 at 30, 37 and 44 DAS over control. Fe foliar spray enhanced nitrogen (N), phosphorus (P), potash (K) and iron (Fe) content of herbage, however Mn content decreased due to antagonism. Increased herbage quality and estimated digestibility parameters like crude protein (CP), total digestible nutrients (TDN), digestible dry matter (DDM), digestible crude protein (DCP), dry matter intake (DMI), relative feed value (RFV), relative forage quality (RFQ), net energy for lactation (NEL), digestible feed energy (DFE) and reduction in fibers were recorded with three 1.0% foliar sprays of Fe. Gross return, net field benefit (NFB), benefit cost ratio of teosinte crop improved with foliar Fe application. Maximum rate of returns (400%) were recorded with three 1.0% FeSO4 at 30, 37 and 44 DAS. Thus, we conclude that three foliar sprays of 1.0% FeSO4 enhanced the teosinte growth, yield and quality which will certainly improve livestock production. © 2016 Friends Science Publishers

Regulation of macro, micro, and toxic element uptake by Salix × smithiana using liming of heavily contaminated soils

Willow cultivation in soils heavily contaminated by risk elements is a challenging issue due to phytotoxic effects that restrict plant growth. Liming reduces the mobility of some risk elements in contaminated soils and therefore can be a suitable measure for contaminated soils but can also affect availability of nutrients for planted willows. We investigate how liming affects concentrations of macro, micro, and toxic elements in the organs of willows planted in contaminated soils. We established a 3-year pot experiment with Salix × smithiana planted in weakly acid and alkaline soils anthropogenically seriously contaminated by As, Cd, Pb, and Zn. Soils were both untreated and treated with two doses of lime and dolomite in the first year before planting. We determined biomass production, mortality, and the concentration of macro- and micronutrients and toxic elements in the willows’ aboveground organs. Lime application increased biomass production in both soils; dose of lime played an important role for its increase only in alkaline soil. Lime in a higher dose was incompatible with the vitality of just-planted willows in both soils. Doses of dolomite significantly affected the biomass production and mortality of willows, where lower doses caused a permanent decrease of biomass production and mortality in weakly acid soil. The toxicity of Cd and Zn in leaves was recorded in both untreated soils; the latent deficiency of P and deficiency of Fe in leaves was only recorded in weakly acid untreated soil. Lime application irrespective of dose with foliar Fe application seemed to be the most suitable measure for increasing biomass production and decreasing toxic elements, especially Cd and Zn, without decreasing the macro- and micronutrients in the aboveground organs of willows in weakly acid soil. In alkaline soil, only higher doses of lime had a positive effect on the studied parameters. Dolomite application is not a suitable measure for planting willows in both contaminated soils. Dolomite in a lower dose impairs the growth of willows in weakly acid soil.

Alleviation of Alkalinity-Induced Fe Deficiency in Eggplant (Solanum melongena L.) by Foliar Application of Different Fe Sources in Recirculating System

This study was carried out to investigate the effects of foliar sprays of different iron (Fe) sources on eggplant grown in alkaline aquaponic solutions. Four treatments were used, untreated control, foliar application of iron sulfate (FeSO4), ferric ethylenediaminetetraacetic acid (Fe-EDTA) and ferric ethylenediamine bis(2-hydroxyphenyl)acetic acid (Fe-EDDHA). The results showed that overall growth was significantly increased by foliar Fe application, and the highest values of vegetative growth parameters were recorded in plants treated with FeSO4. The Fe treatment led to a significant increase of shoot Fe concentration, and the highest Fe was observed in plants sprayed with FeSO4, compared to Fe-EDTA and Fe-EDDHA. The lowest chlorophyll content was observed in untreated plants. The highest SPAD index, maximal quantum yield of photosystem (PS II) photochemistry (Fv/Fm) and performance index (PI) values of young and old leaves were found with FeSO4 treatment. It is concluded that application of foliar Fe must be performed in the aquaponic system, to overcome Fe deficiencies in alkaline conditions.

Super-Optimal NPK Along with Foliar Iron Application Influences Bioavailability of Iron and Zinc of Wheat

Deficiency of wheat grain iron (Fe) and zinc (Zn) is common nutritional problem in the developing countries and thus increasing their concentrations is a major challenge. Field experiments were conducted to investigate the effect of different levels of fertilizer nitrogen, phosphorus, potassium (100–200 % NPK) and foliar Fe application (3 % FeSO4.7H2O at 40, 60, and 75 days after sowing) on improving Fe and Zn concentrations in grain and molar ratio of phosphorus/iron (P/Fe) and phosphorus/zinc (P/Zn). Data obtained during the two year (2010–2011 and 2011–2012) field experiment reveals that foliar Fe spray along with fertilizer NPK significantly increased the grain Fe concentration by 6–15 %; whereas a sharp decrease in the grain Zn concentration under super optimal fertilization is attributed to the depressive effect of excessive phosphorus in the treatments. Molar ratio of P/Fe in wheat grains signifies the increased bioavailability of Fe in wheat grains but P/Zn increase under super-optimal NPK application calls for P management to correct the reduced level of Zn in wheat grains.

Effects of Foliar Iron Application on Iron Concentration in Polished Rice Grain and Its Bioavailability

Iron (Fe) deficiency in humans caused by inadequate dietary intake is a global nutritional problem. A glass house pot experiment was conducted to evaluate the effect of foliar FeSO₄ containing applications on concentrations of Fe, Zn, and Fe bioavailability in polished rice among five rice cultivars. The results showed that foliar application of FeSO₄, FeSO₄, plus nicotianamine (NA), and FeSO₄ plus NA with ZnSO₄ increased the grain Fe concentration by 16.97%, 29.9%, and 27.08%, respectively. The grain Fe bioavailability also increased by foliar application of FeSO₄, FeSO₄ plus NA, and FeSO₄ plus NA with ZnSO₄; these represent increases of 12.63%, 20.86%, and 18.75%, respectively. Foliar FeSO₄ containing applications improved the Fe bioavailability and might be attributed to the reduction of phytic acid and the increase of Fe concentration in polished rice. Addition of ZnSO₄ to foliar Fe application increased both Fe and Zn content without altering Fe content and bioavailability. In addition, the cultivar difference in Fe and Zn concentration was observed and may be due to the genetic control of leaf absorption and seed deposition of foliar application. Furthermore, the cultivar difference in Fe bioavailability observed might be attributed to the variation of grain Fe, phytic acid, and total phenolics contents among the five rice cultivars. The results suggested that foliar FeSO₄ containing applications represent a promising agricultural approach to reduce Fe deficiency in countries where polished rice is extensively consumed.

Effects of foliar spray of different Fe sources on pepper (Capsicum annum L.) plants in aquaponic system

An experiment was carried out to investigate the effects of foliar applications of different Fe sources on pepper plants grown in alkaline aquaponic solutions. Common carp was stocked in the rearing tanks at 50fishm−3. The fish were fed three times daily with a pellet diet containing 46% protein. Twenty days old pepper seedlings were transplanted on to growth bed units of aquaponic system after stocking of carp fish for 2 months in the rearing tanks. Foliar nutrients application began 30 days after transplantation. Four treatments were used, untreated control, foliar application at the rate of 200mLplant−1 with 0.5gFeL−1 FeSO4, Fe-EDTA, and Fe-EDDHA. Plants were sprayed twice a month. The results showed that overall growth was significantly increased by foliar Fe application, and the highest values of vegetative and reproductive growth parameters were recorded in plants treated with FeSO4. The lowest chlorophyll content was observed in untreated plants. The highest SPAD index, maximal quantum yield of PS II photochemistry (Fv/Fm) and performance index (PI) values of young and old leaves were found with FeSO4, with no difference between Fe-EDTA and Fe-EDDHA treatments. The Fe treatment led to a significant increase of shoot Fe concentration in pepper plants, so that the highest shoot Fe concentration was observed in plants sprayed with Fe-sulfate, whereas Fe-EDTA and Fe-EDDHA led to intermediate concentrations and control led to the lowest one. Foliar fertilization of pepper plants with different Fe sources had a beneficial effect on the essential nutrient uptake and transport in plants. Thus, present results revealed that application of foliar Fe must be performed in the aquaponic system, to overcome Fe deficiencies in alkaline conditions and to make better nutritional status.

Management Strategies for Increasing Soybean Yield on Soils Susceptible to Iron Deficiency

Soybean [Glycine max (L.) Merr.] production has increased by more than 55,000 ha in the last 25 yr in the western third of Kansas, a region with soils that can be prone to Fe chlorosis. The objective of this study was to evaluate the relative effectiveness of varietal selection, seed‐applied Fe fertilizer, and foliar Fe application to reduce the incidence of Fe chlorosis under irrigated soybean production. Seven locations with a history of Fe deficiency in soybeans were selected. The study consisted of a factorial design with three foliar treatments (two chelated Fe fertilizer forms and no foliar), two seed‐applied Fe fertilizer treatments (with and without chelated Fe fertilizer), and two different varieties (a nontolerant and tolerant commercial variety). Plant population, chlorophyll meter (CM) readings (V3 and V6 growth stage), plant height at maturity, and grain yield were measured. Foliar Fe application did not affect any plant parameter except for CM reading and grain yield at one location. However, the use of seed‐applied chelated Fe fertilizer significantly increased CM readings at the V3 and V6 growth stages, plant height at maturity, and grain yield across all locations. Given soil conditions conducive to the development of severe iron chlorosis, seed‐applied chelated Fe fertilizer increased yields by approximately 55% for both varieties. Chlorosis quantified as CM readings at V3 to V6 growth stage may not be correlated to the yield potential of a variety in all environments. This suggests that producers should choose the best varieties primarily based on yield potential if supplemental seed‐applied Fe fertilizer will be used.

Iron and Zinc Concentrations in Grain and Flour of Winter Wheat As Affected by Foliar Application

Human deficiencies of iron (Fe) and zinc (Zn) are worldwide problems. Biofortification of wheat could reduce Fe and Zn deficiencies in societies that depend on wheat consumption. This study investigated the effects of foliar application of Fe with or without Zn on the concentrations of Fe and Zn in grain and especially in flour of three wheat cultivars. On average, grain Fe concentration was increased significantly from 29.5 mg kg(-1) in the control to 37.8, 35.9, or 34.9 mg kg(-1) by application of FeSO4, ferric citrate plus ZnSO4, or ferric citrate, respectively. As expected, grain Zn concentration was increased from 29.0 mg kg(-1) in the control to 45.7 or 39.6 mg kg(-1) by application of ferric citrate plus ZnSO4 or a complex of micronutrients. Although the Fe and Zn concentrations in flour were inherently lower than in bran and shorts made by experimental mill, the concentrations in flour were simultaneously increased from 10.4 to 12.4 mg kg(-1) for Fe and from 11.8 to 17.4 mg kg(-1) for Zn by application of ferric citrate plus ZnSO4. Importantly, Fe was peripherally localized within grain fractions and strictly limited to transport to endosperm, making it more difficult to increase the quantity of Fe in flour products by foliar Fe application, but the situation with Zn is promising because Zn is more readily transported to the endosperm than Fe. The current study increases the understanding of agronomic biofortification.

Foliar Iron Fertilization of Peach (Prunus persica (L.) Batsch): Effects of Iron Compounds, Surfactants and Other Adjuvants

Experiments to assess the capability of different combinations of iron (Fe) compounds and adjuvants to provide Fe via foliar application to Fe-deficient plants have been carried out. A total of 80 formulations containing (1) one of five Fe-compounds [FeSO4·7H2O, Fe(III)-citrate, Fe(III)-Ethylenediaminetetraacetic acid (EDTA), Fe(III)-Diethylenetriamine pentaacetic acid (DTPA), Fe(III)-Iminodisuccinic acid (IDHA)], (2) a surfactant (Mistol, alkyl-polyglucoside1 or alkyl-polyglucoside2), and (3) an adjuvant (glycerol, methanol or glycine–betaine) were studied with respect to leaf wetting ability and surface tension. From the initial formulations only 26 resulted in adequate leaf wetting, 20 with alkyl-polyglucoside2 and 3 each with Mistol and alkyl-polyglucoside1, and some of them (four with alkyl-polyglucoside2, one with Mistol, and three with alkyl-polyglucoside1) were found to have inadequate surface tension values for use as foliar fertilizers. In a second experiment, 20 formulations containing alkyl-polyglucoside2 and one each of the five Fe-compounds and adjuvants listed above, were used for a foliar experiment with Fe-deficient peach trees [Prunus persica (L.) Batsch] grown under field conditions. Iron-deficient shoots were sprayed only once and leaf re-greening was assessed over 6 weeks for leaf chlorophyll content (via SPAD measurements) and percentage of green leaf area (via image analysis). Foliar Fe application always resulted in leaf Chl increases, although different degrees of re-greening were observed for the various Fe-compounds tested. Best results were obtained after treatment with formulations containing (in a decreasing order): Fe(II)-sulfate, Fe(III)-citrate, Fe(III)-EDTA, Fe(III)-IDHA, and Fe(III)-DTPA. A positive effect of adding glycerol, methanol or glycine–betaine was often observed, although the effect depended on each Fe-containing compound, indicating the existence of significant interactions between spray components. Results are of importance while trying to critically evaluate the potential of Fe sprays as a viable strategy to remedy plant Fe deficiency under field conditions.

Iron supply to tobacco plants through foliar application of iron citrate and ferric dimerum acid

Experiments to assess the re‐greening and the distribution of leaf‐applied iron (Fe) within the aerial organs were developed with tobacco (Nicotiana tabacum L.) plants. Fe (III)‐citrate and Fe‐dimerum acid were applied to a part of the leaf and plant re‐greening was monitored for 6 weeks after treatment. Fluid Fe increments associated with foliar Fe application were measured within 3 days after application. Fe distribution from the site of application within the leaf and the untreated above‐ground plant parts was evaluated. Leaf fluid Fe concentration was determined by a novel procedure based on Fe chelation by desferrioxamine E and high performance liquid chromatography separation on a reversed‐phase column. The ferrioxamine E method enabled accurate determination of small amounts of Fe present in leaf fluid. Foliar Fe‐dimerum acid and Fe (III)‐citrate treatment to chlorotic tobacco plants induced new growth re‐greening. It was concluded that the applied Fe‐containing compounds penetrated the leaf, were distributed within the plant and that Fe supplied as both complexes could be utilized by the plant cell.