Influences of ultra‐violet (UV)‐blue light radiation on the growth of cotton. I. Effect on iron nutrition and iron stress response

Cool white fluorescent (CWF) light reduces Fe³⁺ to Fe²⁺ while low pressure sodium (LPS) light does not. Cotton plants grown under CWF light are green, while those yrown under LPS light develop a chlorosis very similar to the chlorosis that develops when the plants are deficient in iron (Fe). It could be that CWF light (which has ultra violet) makes iron more available for plant use by maintaining more Fe²⁺ in the plant. Two of the factors commonly induced by Fe‐stress in dicotyledonous plants‐‐hydroyen ions and reductants released by the roots‐‐were measured as indicators of the Fe‐deficiency stress response mechanism in M8 cotton.

The plants were grown under LPS and CWF light in nutrient solutions containing either NO₃‐N or NH₄‐N as the source of nitrogen, and also in a fertilized alkaline soil. Leaf chlorophyll concentration varied significantly in plants grown under the two light sources as follows: CWF+Fe > LPS+Fe > CWF‐Fe ≥ LPS‐Fe. The leaf nitrate and root Fe concentrations were significantly greater and leaf Fe was generally lower in plants grown under LPS than CWF light. Hydrogen ions were extruded by Fe‐deficiency stressed roots grown under either LPS or CWF light, but “reductants”; were extruded only by the plants grown under CWF light. In tests demonstrating the ability of light to reduce Fe³⁺ to Fe²⁺ in solutions, enough ultra violet penetrated the chlorotic leaf of LPS yrown plants to reduce some Fe³⁺ in a beaker below, but no reduction was evident through a yreen CWF grown leaf.

The chlorosis that developed in these cotton plants appeared to be induced by a response to the source of liyht and not by the fertilizer added. It seems possible that ultra violet liyht could affect the reduction of Fe³⁺ to Fe²⁺ in leaves and thus control the availability of this iron to biological systems requiring iron in the plant.     

Monocot‐dicot variability in response to an iron oxide‐metallic iron source

Abstract

Iron from a mixture of Fe oxide and metallic Fe was more available to corn (Zea mays L.) than it was to soybeans when the plants wore grown in calcareous soil or in nutrient solution. All this Fe, however, was DTPA (diethylene triamine pentaacetic acid) extractable. In solution culture the Fe was available to the soybean (Glycine max L.) plants unless CaCO₃ was included in the nutrient solution.     

Soybean response to iron‐deficiency stress as related to iron supply in the growth medium

The Fe‐inefficient T203 and the Fe‐efficient A7 and Pioneer 1082 (P1082) soybeans (Glycine max (L.) Merr.) were grown hydroponically with no (0 mg Fe L^‐1 ; ‐Fe) and a minute level (0.025 mg Fe L^‐1 ; +Fe) of Fe to (a) compare their responses to Fe‐deficiency stress and (b) relate Fe‐efficiency in soybeans to their ability to initiate the Fe‐stress‐response mechanism at low levels of Fe. With no Fe in solution, P1082 released similar levels of H⁺ ions, but released less reductant from their roots and there was less reduction of Fe³⁺ to Fe²⁺ by their roots than by A7 roots. These responses were also one day later and occurred after a more severe chlorosis and a lower leaf Fe had developed in P1082 than in A7. With 0.025 mg L^‐1 of solution Fe, it was not necessary for the Fe‐stress response mechanism to be fully activated to make Fe available in A7 soybean, whereas a strongly enhanced Fe stress response was observed in P1082. Increased Fe uptake and regreening of leaves immediately succeeded initiation of the Fe stress response in both cultivars and at both levels of Fe. Thus, P1082 was slightly less efficient than A7 soybean, but would be classed more efficient than the previously studied soybean cultivars A2, Hawkeye, Bragg, Pride, Anoka, and T203. These results support the hypothesis that the most efficient soybeans are those which can initiate the Fe‐stress response mechanism with little or no Fe in the growth medium. The near simultaneous occurrence of the factors in the Fe‐stress response mechanism (H ion and reductant release, reduction of Fe to Fe by roots), and the immediate increase in leaf Fe and chorophyll contents following that response suggest that all these factors act in concert, not independently, to aid in the absorption and transport of Fe to plant tops.     

Influence of pH, iron source, and Fe/ligand ratio on iron speciation in lignosulfonate complexes studied using Mössbauer spectroscopy. Implications on their fertilizer properties

Iron chlorosis is a very common nutritional disorder in plants that can be treated using iron fertilizers. Synthetic chelates have been used to correct this problem, but nowadays environmental concerns have enforced the search for new, more environmentally friendly ligands, such as lignosulfonates. In this paper, Fe coordination environment and speciation in lignosulfonate (LS) complexes prepared under different experimental conditions were studied by (57)Fe M?ssbauer spectroscopy in relation to the Fe-complexing capacities, chemical characteristics of the different products, and efficiency to provide iron in agronomic conditions. It has been observed that the complex formation between iron and lignosulfonates involves different coordination sites. When Fe(2+) is used to prepare the iron-LS product, complexes form weak adducts and are sensitive to oxidation, especially at neutral or alkaline pH. However, when Fe(3+) is used to form the complexes, both Fe(2+) and Fe(3+) are found. Reductive sugars, normally present in lignosulfonates, favor a relatively high content of Fe(2+) even in those complexes prepared using Fe(3+). The formation of amorphous ferrihydrite is also possible. With respect to the agronomical relevance of the Fe(2+)/Fe(3+) speciation provided by the M?ssbauer spectra, it seems that the strong Fe(3+)-LS complexes are preferred when they are applied to the leaf, whereas root uptake in hydroponics could be more related with the presence of weak bonding sites.     

Arsenic–iron interaction: Effect of additional iron on arsenic-induced chlorosis in barley grown in water culture

Abstract

The effect of additional iron (Fe) on arsenic (As) induced chlorosis in barley (Hordeum vulgare L. cv. Minorimugi) was investigated. The treatments were: (1) 0?μmol?L^?1 As?+?10?μmol?L^?1 Fe³⁺ (control), (2) 33.5?μmol?L^?1 As?+?10?μmol?L^?1 Fe³⁺ (As-treated) and (3) 33.5?μmol?L^?1 As?+?50?μmol?L^?1 Fe³⁺ (additional-Fe³⁺) for 14?days. Arsenic and Fe³⁺ were added as sodium-meta arsenite (NaAsO₂) and ethylenediaminetetraacetic acid-Fe³⁺, respectively. Chlorosis in fully developed young leaves was observed in the As-treated plants. The chlorophyll index and the Fe concentration decreased in shoots of the As-treated plants compared with the control plants. Arsenic reduced the concentration of phosphorus, potassium, calcium, magnesium, manganese, zinc and copper. The additional-Fe³⁺ treatment increased the chlorophyll index in plants compared with the As-treated plants. Among the elements, Fe concentration and accumulation specifically increased in the shoots of additional-Fe³⁺ plants compared with As-treated plants, indicating that As-induced chlorosis was Fe-chlorosis. Arsenic and Fe were mostly concentrated in the roots of the As-treated plants. Despite inducing chlorosis in the As-treated plants, phytosiderophores (PS) accumulation in the roots and release from the roots did not increase, rather PS accumulation decreased, indicating that As toxicity hindered PS production in the roots. The PS accumulation in the roots was further reduced in the additional-Fe³⁺ treatment.     

Nitric acid‐ and o‐phenanthroline‐extractable iron for diagnosis of iron chlorosis in citrus lemon trees

Abstract

Plant analysis for total iron (Fe) is frequency used for diagnosis of Fe‐deficiency chlorosis. However, chlorotic plants frequency contained similar or higher amount of total Fe than the healthy green plants. The objectives of this study were to (i) determine if Fe chlorosis in citrus lemon can be diagnosed by total or active Fe and can be related to the degree of chlorosis, and (ii) determine the optimum extraction time and ratio of extracting solution to plant sample for extracting the active Fe. Leaf samples of different degrees of Fe chlorosis were sampled from different citrus lemon trees from three different sites. Total Fe was extracted with nitric acid (HNO₃) and active Fe with o‐phenanthroline from lemon leaves. An extraction time of 20 and 45 hours and the ratios of the extractor to the sample of 5:l, 10:1, and 20:1 were investigated. The results indicated that an extraction time of 20 hours is enough for extracting the active Fe from citrus lemon leaves by o‐phenanthroline. The amount extracted by all ratios (5:1, 10:1, and 20:1) were detectable and at the same time similarly and consistency showed the differences in degrees of chlorosis in all plant samples. Total Fe content was always higher in moderately and severely chlorotic leaves compared to the green leaves and was not related to the degree of chlorosis. Therefore, total Fe cannot be used as a criteria to differentiate between the Fe‐deficient and non‐deficient plants. On the other hand, active Fe tended to decrease with the increase in the degree of chlorosis. The ratio of active to total Fe was calculated and was found to be closely correlated with the degree of chlorosis. This clearly illustrates the failure of plant analysis for total Fe and the effectiveness of active Fe and/or the ratio of active to total Fe for diagnosing Fe chlorosis.     

Influences of ultra‐violet (UV)‐blue light radiation on the growth of cotton. II. Photosynthesis,leaf anatomy,and iron reduction

Cotton (Gossypium hirsutum L.) plants grown under low pressure sodium lamps (LPS) developed chlorosis which was similar in appearance to iron‐stress induced chlorosis, while plants under cool white fluorescent lamps (CWF) at the same level of photosynthetically active radiation (PAR) developed normally. These illumination sources differ in spectral irradiance; CWF lamps emit ultra violet (UV), whereas LPS lamps do not. Ultraviolet radiation is capable of reducing Fe³⁺ to Fe²⁺ through a chlorotic leaf which may be important in establishing an active iron fraction in the leaf. Root reduction of Fe³⁺ to Fe²⁺ was lacking in Fe‐stressed cotton under LPS light, but was present under CWF light. Net photosynthesis, photosynthetic electron transport, and leaf chlorophyll content were lower under LPS than CWF light in most of the growing media studies (soil or solutions with nitrate‐ or ammonium‐nitrogen supplied). Chloroplast ultrastructure and leaf thickness were also altered by LPS irradiance. Electron microscopic studies with plants grown in nutrient solutions for 4 weeks suggested that chioroplastic granal disorganization was more directly associated with diminished iron supplies than with light source. However, plants grown in soil for 6 weeks under LPS light had granal disorganization similar to that found in iron‐stressed plants. These studies suggest an important role for UV radiation in influencing the activity of iron in plants.     

Chelation effects on the iron reduction and uptake by low‐iron stress tolerant and non‐tolerant citrus rootstocks

The relative rates of ferric‐iron (Fe³⁺) reduction and uptake by two citrus rootstocks were measured for a series of synthetic Fe³⁺ chelates and microbial siderophores. The rates of Fe³⁺ reduction by the citrus seedlings followed the order: FeHEDTA >> FeDPTA > FeCDTA. No reduction occurred for FeDFOB (ferrioxamine B) and FeTAF (ferric triacetylfusagen). Low rates of Fe³⁺ reduction occurred for Fe2RA3 (ferric rhodotorulic acid). The levels of ⁵⁵Fe taken up the citrus seedlings showed good correlations with the reduction rates. These results indicate the importance of Fe³⁺ reduction in the Fe uptake by citrus rootstocks. The immobility of a large percent of the ⁵⁵Fe taken up by the roots is attributed to the accumulation of Fe in the root apoplasts.     

Reduction of structural iron in selected iron‐bearing minerals by soybean root exudates grown in an in vitro geoponic system

Research on the reduction of iron (Fe) by plant‐root exudates has been conducted using hydroponic solutions containing Fe salts or chelates. These solutions, however, fail to reflect the true soil environment because plants derive their majority requirement from the solid Fe(III) sources. An in vitro Geoponic system (IVGS) is developed to study the reduction of Fe‐bearing clay minerals, i.e., Upton and SWa‐1 (smectite), and Si‐containing amorphous Fe oxide by soybean‐root exudates. Surface sterilized soybean seeds, [Glycine max (L.) Men.] cv. Williams (marginally susceptible to Fe chlorosis), were germinated in presterilized glass culture tubes containing semi‐solid agar media (sucrose free) and Fe minerals. These tubes were placed in an incubator programmed for a white‐fluorescent light cycle for 16 h and temperature setting of 25±2°C. After 15 d of plant growth, the system was analyzed for Fe²⁺ and total Fe. The amount of structural Fe reduction was 0.012, 0.095 and 0.182 mmol/g for Upton, SWa‐1, and Si‐containing amorphous Fe oxide samples, respectively. The reduction of structural Fe in the Fe containing minerals was likely caused by phenolic root exudates which oxidized to diquinones.     

Phytosiderophore release from manganese‐induced iron deficiency in barley

An experiment was conducted in the phytotron with barley (Hordeum vulgare L. cv. Minorimugi) grown in nutrient solution to compare iron (Fe) deficiency caused by the lack of Fe with manganese (Mn)‐induced Fe deficiency. Dark brown spots on older leaves and stems, and interveinal chlorosis on younger leaves were common symptoms of plants grown in either Mn‐toxic or Fe‐deficient treatments. Dry matter yield was affected similarly by Fe deficiency and Mn toxicity. The Mn toxicity significantly decreased the translocation of Fe from roots to shoots, caused root browning, and inhibited Fe absorption. The rate of Fe translocated from roots to shoots in the 25.0 μM Mn (toxic) treatment was similar to the Fe‐deficient treatment. Manganese toxicity, based on the release of phytosiderophore (PS) from roots, decreased from 25.0>250>2.50 uM Mn. The highest release of PS from roots occurred 7 and 14 days after transplanting (DAT) to Mn‐toxic and Fe‐deficient treatments, respectively; but was always higher in the Fe‐deficient treatment than the Mn‐toxic treatments. The release of PS from roots decreased gradually with plant age and with severity of the Mn toxicity symptoms. The PS content in roots followed the PS release pattern.     

Prof. Dr. Habil. Dr. H. C. Martin Körschens Zum 65. Geburtstag

Minimierung von Stoffbelastungen und Sicherung der Nachhaltigkeit sind die beiden Seiten, die Kriterienauswahl und Bewertungsprozeß der Kategorie Düngung prägen.

Das Gefährdungspotential der Kategorie wird durch 13 quantifizierbare und kontrollfähige Kriterien beschrieben. Für diese werden ökologische Optima und kritische Belastungen definiert, die die Grundlage für Bewertungsprozesse von Landwirtschaftsbetrieben bilden. Gleichzeitig wird damit ein Rahmen vorgegeben, der standortbezogen den tolerierbaren und damit umweltverträglichen Bereich der Düngung absteckt. Mittels dieses Rahmens können Betriebe umfassend bewertet, Problemfelder identifiziert und Korrekturerfordernisse formuliert werden.     

Differential response of groundnut genotypes to iron‐deficiency stress

Differential response of groundnut genotypes to iron‐deficiency stress was studied in soils containing high calcium carbonate. Genotypes differed significantly for some traits that appeared to be important in determining adaptation to low iron. The genotypes TCGS 273, TCGS 2, TCGS 37, and Kadiri 3 had higher total chlorophyll, total dry matter, and active iron (Fe²⁺) contents under iron‐deficiency stress conditions. Total chlorophyll followed by active iron were found to be sensitive parameters to Fe deficiency. Based on the visual deficiency symptoms (chlorosis score), the genotypes were classified into three groups. Efficient (no genotype was found efficient), moderately efficient (TCGS 273, TCGS 2, TCGS 3, and Kadiri 3), and inefficient (TCGS 1, TCGS 7, TCGS 11, TCGS 26, TCGS 28, TCGS 29, TCGS 30, TCGS 1518, TPT 1, TPT 2, ICGS 11, ICGS 44, Girnar, JL 24, ICGS(E) 21, and TMV 2).     

Tumorous crown gall response to iron‐deficiency stress in sunflower

Tumorous crown gall tissue in sunflower (Helianthus annus L.) initiates a mechanism for making Fe available to itself as evidenced by its ability to reduce Fe³⁺ to Fe²⁺. The objective of this study was to determine if a limited Fe supply to the plant might affect the growth, nutrition and reduction of Fe³⁺ to Fe²⁺ by the tumorous crown gall. Healthy green 14‐day‐old sunflower plants (cv mammoth Russian) were either stem‐inoculated with Agrobacterium tumefaciens to induce tumorous crown gall tissue development or were left uninoculated for comparison. The plants were grown in a modified Hoagland nutrient solution with treatments containing 0.0, 0.15, 0.6 and 2.0 mg Fe L^‐1. The 0 mg Fe L^‐1 treatment induced maximum Fe chlorosis, and consequently there was a release of hydrogen ions and of a yellow pigment by the roots, but there was no measureable release of ‘reductants’ by the roots. Iron‐deficiency stress (0 mg Fe L^‐1) also resulted in reduced tumorous crown gall growth, less reduction of Fe³⁺ to Fe²⁺, and lower levels of Fe in the tumorous tissue compared to tumorous tissues adequately supplied with Fe. The tumorous crown gall tissue on the stem reduced much more Fe³⁺ to Fe²⁺ than the nontumorous stem tissue regardless of Fe level in the treatment. Tumor tissue contained more Fe, Cu and P than the nontumorous stem tissues which may indicate a modified metabolism in this tissue. An abundant supply of Fe seems to enhance the development and growth of the tumorous crown gall tissue and a deficient supply of Fe retards its growth.     

Could iron nutrition status be evaluated through photosynthetic pigment changes?

Iron deficiency decreases the amount of photosynthetic pigments in higher plants, and also results in characteristic changes in the relative photosynthetic pigment composition. Iron deficient plants exhibit a relative increase in xanthophylls, largely attributable to pigments within the xanthophyll cycle, violaxanthin, antheraxanthin, and zeaxanthin. Furthermore, the xanthophyll cycle functions in Fe‐deficient plants, but not in other yellow, carotenoid enriched‐materials, such as etiolated or senescing leaves. When Fe‐deficient leaves are illuminated, part of the violaxanthin is converted into antheraxanthin and zeaxanthin. When Fe‐deficient leaves are placed in the dark, the cycle reverts back to violaxanthin. In this paper we present further data on this cycle and discuss the possible relevance of pigment changes as an alternative mechanism for the dissipation of excess energy. The possibility of using characteristic pigment changes as a tool for monitoring Fe status in higher plants is discussed.     

Manganese‐iron relationship in soybean grown in calcareous soils 1

Although a positive response to iron (Fe) is, usually, expected in calcareous soils; this has not been always the case; and in some instances a depressing effect has been observed. An induced micronutrient imbalance is suspected. This experiment was designed to study the effect of Fe fertilizer on the plant micronutrients. Twenty three highly calcareous soils (18–46% calcium carbonate equivalent; pH 7.7–8.4; and a wide range of extractable Fe) from southern Iran were used in an eight‐week greenhouse experiment to study the effect of Fe fertilizers on soybean [Glycine max (L.) Merr.] growth and chemical composition. The statistical design was a 23 × 3 factorial arranged in a completely randomized block with three replications. Treatments consisted of 23 soils and three levels of applied Fe (0, 10, and 20 mg Fe/kg as FeEDDHA). Uniform doses of nitrogen (N), phosphorus (P), copper (Cu), manganese (Mn), and zinc (Zn) were applied to all pots. Dry matter (DM) and micronutrients concentrations and uptakes of plant tops were determined and used as the plant responses. Application of Fe either had no significant effect on DM or even decreased it. The plant concentration and uptake of Fe increased significantly in all soils. The concentrations and uptakes of Cu and Zn did not change but those of Mn decreased significantly. The negative effect of Fe application was, therefore, attributed to the interference of Fe with Mn nutrition. The mechanism involved appears to be the restriction in Mn translocation from soil to root and/or from root to the plant tops.     

Evaluating iron‐impregnated paper strips for assessing available soil phosphorus

Abstract

Iron (Fe)‐impregnated filter paper strips (Pi) have been proposed as a method for measuring available soil phosphorus (P). A well‐defined Pi method has not yet been developed and Pi strips are often prepared with different filter papers and procedures. A study aimed at arriving at a consistent Pi method is thus needed. Four types of Pi strips, prepared with the two most widely used papers, Whatman No. 50 and 541, following a procedure that incorporates improvements both proposed in the literature and made in our laboratory, were evaluated for P extraction capacity and error. Two of the best strips, which are significantly different in P extraction capacity, along with the Mehlich 1 (0.05M HCl and 0.0125M H₂SO₄) and the Olsen method (0.5M NaHCO₃, pH 8.5) were further evaluated in a greenhouse experiment involving eight soils planted with corn (Zea mays L.). Results indicated that strips prepared with both Whatman No. 50 and 541 were appropriate for P extractions as long as strips were washed with deionized water after treatment with ammonium hydroxide (NH₄OH). At room temperatures the strips probably contain both hydrous Fe hydroxides and oxides in both crystalline and amorphous forms. Pi P was well correlated with Olsen P and P uptake in all soils, indicating that Pi is generally applicable in diverse soils. No obvious advantage was found for the Pi with respect to the Olsen method. Both the Pi and the Olsen method were better extractants with respect to the Mehlich 1, which was ineffective for extracting P in calcareous soils. Extractable P by Mehlich 1, Olsen, and Pi all correlated highly with accumulated plant available P estimated by eight sequential crops in the greenhouse. However, none of the methods could account for all the variation in plant P removal.     

Microbial DNA extraction and analyses of soil iron–manganese nodules

Iron–manganese (Fe–Mn) nodules and concretions are soil new growth, reflecting soil environmental conditions during their formation. Bacteria play a dominant role in the oxidation of dissolved Mn(II) in aqueous systems and the formation of marine and freshwater Fe–Mn nodules. However, the role and significance of bacteria in soil Fe–Mn nodule formation have not been well recognized. In this paper, microbial DNA was directly extracted from two Fe–Mn nodule samples collected from Wuhan and Guiyang in central China. The extracted DNA was amplified by polymerase chain reaction (PCR) and cloned. The clones were then screened by amplified ribosomal DNA restriction analysis (ARDRA). Twenty patterns were obtained for Wuhan sample and Guiyang sample, respectively. DNA sequencing and phylogenetic analyses revealed that the bacterial compositions of the Fe–Mn nodules were mainly belonged to Firmicutes, β-proteobacteria, γ-proteobacteria branches of the domain bacteria. These divisions had close relativeness with Mn(II)-oxidizing bacteria identified from marine Fe–Mn nodules, implying the possible contributions of these bacteria to soil Fe–Mn nodule formation.     

Behavior of iron‐supplying materials in incubated calcareous soils 1

Two Fe chlorosis‐inducing calcareous soils were incubated for up to 5 months, at room temperature and field capacity, with Fe‐EDDHA, Fe‐DTPA, FeSO₄, an amino acid chelate “Fe‐Metalosate”;, an oxide “Micronized‐Iron”;, and a precipitated Fe‐S compound “Iron‐Sul”;. Other treatments included DTPA chelate alone, elemental S and H₂SO₄ at comparable rates. Both water‐soluble, and DTPA‐extractable Fe fractions were measured periodically from each sample. All water‐soluble sources decreased with time. Soluble Fe was highest after Fe‐EDDHA addition but was not detectable after “Fe‐Metalosate”; and FeSO₄. Acidification to neutralize CaCO₃ significantly increased DTPA‐extractable Fe, which remained high with increasing incubation time. “Micronized‐Iron”; and S had only a slight effect on DTPA‐ extractable Fe. Though Fe‐EDDHA is the most efficient Fe material, pelleted acidified Fe sources, i.e., “Iron‐Sul”;, may be more economical for some crops in the long term.     

On‐farm diagnosis and management of iron chlorosis in groundnut

Abstract

Iron (Fe) chlorosis is a major nutritional constraint to groundnut (Arachis hypogaea L.) productivity in many parts of the world. On‐farm research was conducted at a Fe‐chlorotic site to evaluate the performance of three genotypes (TMV‐2, ICGS‐11, and ICGV‐86031), three fertilizer practices [no fertilizer control, fanners practice (125: 200: 0 kg NPK ha^?1), recommended practice (20: 50: 30 kg NPK ha^?1)], and two Fe treatments (non‐sprayed control and foliar FeSO₄ sprays) for their effect on Fe‐chlorosis and haulm and pod yields. These treatments were tested in a strip‐split plot design with four replicates. Results revealed that TMV‐2 and ICGS‐11 were susceptible to Fe‐chlorosis and produced significantly smaller haulm and pod yield, whereas, ICGV‐8603 1 was tolerant to Fe‐chlorosis. Farmer's fertilizer practice had the highest incidence of Fe‐chlorosis. Extractable Fe and chlorophyll content in the fresh leaves were the best indices of Fe‐status and were significantly (P<0.01) correlated with visual chlorosis ratings. Foliar application of FeSO₄ (0.5 w/ v) was effective in correcting Fe‐chlorosis and increased pod yield by about 30 to 40% in susceptible genotypes. These results suggests that use of tolerant genotypes such as ICGV‐86031 or foliar application of FeSO₄ in susceptible genotypes such as TMV‐2 and ICGS‐11 in combination with recommended fertilizer levels is an effective management package for alleviating Fe‐chlorosis in groundnut.     

Lime chlorosis on photosynthesis and transpiration of iron‐inefficient soybeans

Abstract

Iron deficiency in PI54619–5–1 soybeans (Glycine max L.) decreased growth 37% and decreased the rate of photosynthesis by 33%, but had no influence on the rate of transpiration. In another experiment Fe deficiency resulted in a mild 18% decrease in the photosynthetic rate and a slight decrease in the transpiration rate. There were no differences in leaf resistances.