Leaf Fe Concentration Research Articles

An iron-deficiency tolerant genotype of sorghum effectively localizes iron to the thylakoid membranes of the bundle sheath cells

ABSTRACT Although sorghum (Sorghum bicolor L.), a C4 grass plant, requires a higher iron (Fe) concentration in its leaves for sufficient growth compared to C3 grass plants, there are differences in Fe-deficiency tolerance among sorghum genotypes. C4 plant sorghum localizes Fe in bundle sheath (BS) cells as a major site for CO2 assimilation; however, the response of chloroplasts in BS cells to Fe deficiency remains unknown. We compared the allocation of Fe and proteins involved in the photosystems between Fe-deficiency-tolerant and Fe-deficiency-susceptible sorghum genotypes. The distribution patterns of the Fe-requiring core proteins of photosystems I and II were the same in both genotypes, whereas the tolerant genotype, line D100, allocated more Fe to the BS thylakoid membranes than the susceptible genotype, regardless of Fe nutritional status and leaf Fe content. These results suggest that the tolerant D100 sorghum line has mechanisms to supply sufficient Fe to the BS thylakoid membranes.

Comparative study of the effectiveness of nano-sized iron-containing particles as a foliar top-dressing of peanut in rainy conditions

The high loss of foliar-applied fertilizers in the wet season and other extreme weather conditions reduces fertilizer use efficiency remarkably low. Emerging nano-iron materials, owing to their highly desirable properties such as exceptionally small size, particle surface and interface attributes, strong adhesion and high iron ratio, could overcome the limitations of traditional fertilizers. However, their anti-leaching property, leaching resistance mechanism, iron nutrition enrichment capacity and cost effectiveness remain unclear. In this study, four nano-iron materials (Fe nanoparticles (Fe-NPs), Fe3O4-NPs, α-Fe2O3-NPs and γ-Fe2O3-NPs) were compared with traditional iron fertilizers (FeSO4 and Fe-EDTA). The results showed that the efficiency of traditional iron fertilizers decreased greatly under simulated rainfall conditions due to their poor leaching resistance. In contrast, nano-iron fertilizers performed exceptionally well under simulated rainfall conditions with significant increase in leaf iron concentration, photosynthesis and growth of peanut. This was mainly attributed to their decreased contact angle, increased wetting capacity and increased adhesion on plant surface, which collectively decreased fertilizer leaching remarkably. The adhesion capacity of Fe3O4-NPs (53.5 mN/m), was nearly three times that of traditional iron fertilizer (18.3 mN/m). Therefore, only a small amount of Fe3O4-NPs (4 mg/plant) was needed relative to traditional iron fertilizers (FeSO4, 59 mg/plant) to achieve comparable high leaf Fe concentration (1076.96 μg/g) under rainfall conditions. Cost evaluation suggests that the cost-competitiveness of Fe3O4-NPs will become comparable to that of FeSO4 when its price comes down from the current cost of $139/kg to $36/kg, the cost of FeSO4, which is likely considering the pace of nano-material technology development. Together, these results demonstrate the remarkable potential of nano-iron fertilizers in mitigating the escalating fertilizer cost and improving the environmental outcomes of peanut, as well as potentially other crops grown in wet season.

Symptoms of Mn toxicity and the effect of salt on Mn toxicity and accumulation in the halophyte Lepidium latifolium

Manganese (Mn) is an essential micronutrient for higher plants but becomes toxic at excess concentrations in soil. Halophytes are salt-tolerant plants and exhibit a salt-mediated increase in tolerance to other stresses, including heavy metals toxicity. This study investigated Lepidium latifolium (Brassicaceae), a facultative halophyte with invasive behavior and rapid spread under submerged conditions, for Mn accumulation and tolerance in the absence or presence of salt (100 mM NaCl). Under excess Mn concentration (1 mM), toxicity symptoms were observed as black spots on the young leaves but as brown, dark-purple speckles on the older leaves, with colocation of phenolics and Mn. The H2O2 concentration and peroxidase activity in the leaf apoplast were both significantly reduced by excess Mn. This indicated a decrease in the oxidation of MnII and phenolics in the leaf apoplast, likely a mechanism for this species’ high Mn toxicity tolerance. Salt treatment improved the biomass and leaf pigments of Mn-stressed plants, enhanced the activity of antioxidant enzymes, decreased Mn accumulation, and restored the leaf Fe concentration. Our data suggest that L. latifolium is a species with high Mn tolerance and accumulation capacity (∼10 mg g−1 DW) and is suitable for studying salt-induced heavy metal tolerance in Brassicaceae.

Sodium Lignosulfonate Effect on Physiological Traits of Cucumis sativus L. Seedlings

The application of pulp and paper mill sludge to agricultural soils is commonly considered as a strategy to improve soil properties, promote plant growth, and reduce the demand for costly chemical fertilization. The aim of this study was to evaluate if sodium lignosulfonate (sLS), one of the sludges of pulp production, may affect the biomass production, the respiration (R) and net CO2 assimilation rate (An) at the leaf level, and the content and accumulation of trace elements in the leaves of cucumbers grown under a sufficient nutrient supply or soil nutrient deficit. A pot culture experiment was conducted using sLS application rates of 0, 1.0, 2.5, 5.0, and 10 vol% to sandy loam soil. The decline in nutrient availability caused an increase in the R/An ratio and dramatically depressed biomass accumulation. The leaf Fe, Ni, Cr, Co, Al, and Pb contents were lower under low nutrient availability than under sufficient nutrient supply. Although sLS was not very effective in lessening the negative effect of nutrient deficiency on biomass accumulation, it reduced respiratory carbon losses and cell membrane permeability in the leaves of cucumbers grown under nutrient deficit. The reduction in the toxic level of leaf Mn in seedlings grown under sufficient nutrient availability and the toxic level of leaf Fe under a nutrient deficit might also be considered as a positive effect of the sLS application to sandy soil.

Waterlogging effects on leaf element concentrations and cane weight of sugarcane genotypes

Aim: The aim of the present experiment was to examine whether waterlogging induced deficiency or excess of elements, is the cause for reduction in cane weight of sugarcane genotypes under waterlogged conditions. Methodology: The experiment was conducted in pots with eleven sugarcane genotypes grown under control and waterlogged conditions. Waterlogging treatment was imposed at 120 days crop age for a period of 60 days. Cane weight and element concentrations were measured at the end of waterlogging. Results: Compared to control, reduction in cane weight of sugarcane genotypes under waterlogging varied from 5.3% (A-46-11) to 32.3% (CoJ 64). Waterlogging caused a significant decrease in leaf N, P, K, S, Zn and Cu concentrations of sugarcane genotypes; the extent of decreases in leaf N and S were more and values for these elements dropped below their reported critical deficiency level for most genotypes. There was a significant inverse correlation between leaf K and S concentration, and reduction in cane weight of sugarcane genotypes, indicating that genotypes with high leaf K and S under waterlogging have relatively less reduction in cane weight. There were significant increase in the leaf Fe, Al, Mn and Na concentrations under waterlogging, however, increase in these elements were not correlated with reduction in cane weight of sugarcane genotypes. Interpretation: The results suggest that deficiencies of N, K and S rather than excess of Fe, Al and Mn is a major cause for reduction in cane weight of sugarcane genotypes under waterlogged condition. The genotypes tolerant to N, K and S deficiencies under waterlogging can be utilized in breeding program for developing sugarcane varieties with improved waterlogging tolerance. Key words: Cane weight, Element deficiencies, Element toxicities, Sugarcane, Waterlogging

The low ferric chelate reductase activity and high apoplastic pH in leaves cause iron deficiency chlorosis in ‘Huangguan’ pears grafted onto quince A grown in calcareous soil

Quince (Cydonia oblonga Mill.) is a dwarfing rootstock often used in pear cultivation. However, the pear cultivar ‘Huangguan’ (Pyrus bretschneideri Rehd. cv) grafted onto quince A (HG-QA) suffered iron (Fe) deficiency chlorosis in the calcareous soils of North China, while ‘Huangguan’ grafted onto Pyrus betulifolia (HG-PB) did not. We hypothesized that the higher leaf apoplastic pH of HG-QA than HG-PB causes Fe deficiency chlorosis by restricting Fe transportation within leaves. Three-year-old rootstocks quince A and Pyrus betulifolia and the combinations HG-QA and HG-PB were grown in the same orchard in a calcareous soil. Newly expanded leaves were analysed for Fe related properties. Micro X-ray fluorescence analysis was used for Fe mapping within the individual leaves. The extractable Fe(II) concentrations in quince A and HG-QA leaves were much lower than those in Pyrus betulifolia and HG-PB, even though the total leaf Fe concentrations were similar. More Fe was located near the leaf midrib in quince A and HG-QA than in Pyrus betulifolia and HG-PB. These were correlated with the lower ferric chelate reductase (FCR) activity in the chlorotic leaves of the quince A rootstock than Pyrus betulifolia and the lower FCR activity and higher apoplastic pH in the chlorotic leaves of the HG-QA rootstock-scion combination than HG-PB. In conclusion, the reduced Fe availability within the leaves caused by the lower FCR activity and higher apoplastic pH compared with those of HG-PB led to HG-QA leaf chlorosis in calcareous soils. This result implies that rootstocks are involved in the regulation of leaf Fe utilization by scions.

Biofortification and Quality of Collard Greens as a Function of Iron Concentration in Nutrient Solution

The agronomic biofortification of vegetables is a strategy for increasing the concentration of iron (Fe) in food and, consequently, the intake of this micronutrient by the population. When in deficiency, it can cause anemia—a pathology that affects millions of people. Soil-less cultivation is an important cropping system, but there are no studies on how Fe concentrations in a nutrient solution can promote biofortification and affect the quality of collard greens; this is the aim of the present study. For this purpose, five Fe concentrations (2, 4, 6, 8 and 10 mg L−1) were evaluated. Increasing the Fe concentration in the nutrient solution increased the leaf Fe content and decreased the leaf contents of cationic nutrients, without affecting yield. Photosynthetic pigment contents were positively affected by Fe concentrations, while ascorbic acid decreased. There was efficient biofortification of collard greens leaves from 4 mg L−1 Fe, and a higher nutritional quality of leaves was observed at Fe concentrations of 8 mg L−1.

Improving Nutrients Uptake and Productivity of Stressed Olive Trees with Mono-Ammonium Phosphate and Urea Phosphate Application

Nutritional status improvement is a surrogate approach to overcoming undesirable soil conditions. This study was performed in sandy clay loam soil that was characterized by certain undesirable parameters (ECe = 6.4 vs. 7.2 dS m−1, CaCO3 = 8.8 vs. 9.2%, and pH = 7.78 vs. 7.89) on olive (Olea europaea, Arbequina cv.) in the 2020 and 2021 seasons to investigate the influence of two highly soluble phosphorus fertilizers, mono-ammonium phosphate (MAP) and urea phosphate (UP). The treatments included 0.336, 0.445, and 0.555 kg tree−1 for MAP1, MAP2, and MAP3 and 0.465, 0.616, and 0.770 kg tree−1 for UP1, UP2, and UP3, respectively, in comparison to granular calcium super-phosphate (GCSP) at the recommended rate (0.272 kg P2O5 equal 1.75 kg tree−1). This experiment was established according to a randomized complete block design. Generally, our results indicated that both MAP and UP applications surpassed GCSP for all studied parameters except leaf copper uptake in the 2021 season. Moreover, among the HSPFs applied, it was found that applying the maximum levels gave the best results. However, MAP3 gave the maximum values for shoot length, SPAD reading, and dry fruit matter. Moreover, UP3 produced the best results for the leaf area, olive tree yield, total olive yield, total fresh weight, flesh weight (FlW), fruit length (FrL), and leaf Fe content in both seasons.

Seasonal Variation of Leaf Ca, Fe, and Mn Concentration in Six Olive Varieties

Leaf analysis is essential for diagnosing nutritional status and guiding fertilizer application. The present study aimed to investigate the appropriate time for leaf sampling and the effect of genotype on olive nutrition. We determined leaf nutrient concentrations of calcium (Ca), iron (Fe), and manganese (Mn) in five Greek (‘Amfissis’, ‘Chondrolia Chalkidikis’, ‘Koroneiki’, ‘Mastoidis’, and ‘Kalamon’) and one Spanish (‘Picual’) variety from May 2019 to April 2020. The concentrations of Ca, Fe, and Mn were significantly affected by genotype and season. The highest concentrations for all nutrients were determined in April, while the lowest were in May, June, and October. Leaf Ca concentration significantly increased progressively from May to September for all the varieties. Leaves of ‘Koroneiki’ had the highest Ca concentration. Iron concentrations were within the sufficiency thresholds for all the varieties during the whole experimental period, and ‘Mastoidis’ showed the highest concentration. Leaf Mn concentration for all the varieties increased from May to September with an instant decrease in June, apart from ‘Amfissis’. The varieties ‘Kalamon’ and ‘Chondrolia Chalkidikis’ were found to be above the Mn sufficiency threshold throughout the year. Variations among season and genotype depict the complexity of nutrient transportation in leaf tissues.

Nutrient Contents and Productivity of Triticum aestivum Plants Grown in Clay Loam Soil Depending on Humic Substances and Varieties and Their Interactions

Due to an extreme increase in population growth, Egypt suffers from a widening gap in the quantity of imported wheat compared with production and local consumption. Two field trials were conducted during the 2018/2019 and 2019/2020 seasons with three levels of humic substances (HSs) as a foliar spray (1.0, 2.0 and 4.0 g L−1; HS1, HS2 and HS3) and three levels (5.04, 7.56 and 10.08 kg ha−1; HS4, HS5 and HS6) as a soil application. These were applied three times (30, 45 and 60 days after sowing) in comparison with the control (HS0) to evaluate the performance of three wheat varieties (Seds1 (V1), Misr2 (V2) and Giza168 (V3)) grown in clay loam soil. The experiment was set up according to the split-plot structure in a randomized complete block design; however, the varieties were set as the main plot and treatments were a sub-main plot. Generally, the data indicated that the soil application treatments recorded maximum values for most growth and yield attributes, except for spike length and grain weight per spike, SPAD reading and total grain yield in the first season, and leaf area and biological yield in the second season. HS1, HS2, HS5, and HS6 were the superior treatments for most of the nutrient contents studied. Regarding the influence of variety, the results showed that V3 recorded maximum values for LA, SpL, TGW, TGY and leaf Zn and Cu contents in both seasons; PH, GWS and leaf N content in the first season; and SPAD reading, BY and leaf K, Fe and Mn contents in the second season. V1 was the superior variety for GWS, BY, leaf K and Mn contents in the 2018/2019 season and PH, GNS in the second season, followed by V2, which had the greatest values for leaf P contents in both seasons, and SPAD reading, GNS and leaf Fe content in the 2018/2019 season and GWS and leaf N content in the second season.

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 application of micronutrients enhances growth, flowering, minerals absorption and postharvest life of tuberose (Polianthes tuberosa L.) in calcareous soil

Micronutrients applications are effective for better crop production in calcareous soils because these soils are usually deficit in iron (Fe), zinc (Zn) and boron (B). In Pakistan, most of soils are calcareous in nature. When tuberose is grown in such soils as a cut flower, its production is negatively affected. Therefore, a study was aimed to evaluate the effects of micronutrients as foliar sprays on cut tuberose production in calcareous soil. Micronutrients (Fe, Zn and B) alone and in combinations were sprayed on the plants after 60, 90 and 120 days of planting. The mixture of all these three micronutrients increased the plant height (95.77 cm), chlorophyll content (38.13 SPAD), number of leaves (79.63), leaf length (44.73 cm), fresh (111.64 g) and dry (16.16 g) plant weights, root length (15.13 cm), number of stalks (3.73), stalk length (79.03 cm), spike length (22 cm), number of florets (51.67), floret fresh weight (11.85 g), leaf Zn concentration (53.6 mg/g) and vase life (8.4 days). Fe + Zn enhanced the number of leaves (76.60), leaf length (45.83 cm), root length (15.05 cm), spike length (22.33 cm), and leaf Fe (128.18 mg/g) and Zn concentrations (55.02 mg/g). The Fe spray increased the leaf length (44.10 cm), days to flower initiation (142.47 days) and leaf Fe concentration (130.75 mg/g) in tuberose plants. Application of Zn improved the leaf length (45.87 cm) and diameter (1.32 cm), root (15.03 cm), spike (21.77 cm) and floret lengths (4.74 cm), floret dry weight (1.49 g) and leaf Zn concentration (57.5 mg/g). Foliar spray of B increased the B concentration (21.1 mg/g) in tuberose leaves. It is concluded that foliar application of micronutrients alone and in combinations improved the plant growth, flowering, leaf minerals concentrations and vase life of tuberose spikes. However, mixture of Fe, Zn and B was more effective as compared to other treatments. Moreover, current study encourages the foliar application of micronutrients in tuberose when grown in calcareous soils.

Effects of intercropping on growth, elemental composition and antioxidant activity of Artemisia scoparia and Raphanus sativus under lead supply

Artemisia species and radish demonstrate intensive allelopathic properties and high ability to hyperaccumulate heavy metals, but their interaction has not been studied up to date. In a pot experiment, the relationship between wormwood (A. scoparia L.) and radish grown individually or intercropped, without and with Pb(NO3)2 supply, was investigated. The intercropping had significant effects in both species, as a consequence of metal allelopathy. Radish showed decrease of root biomass (1.75- fold), Fe, Mn and Zn content (2-fold), Cu level (5.4-fold), and a 1.59-fold Pb increase in the leaves. In wormwood, a 1.75-fold increase of root biomass, as well as a 7.2- and 2.8-fold increase of root and leaf Fe content, respectively, were recorded. A. scoparia, the most Pb tolerant out of the 11 Artemisia species investigated, accumulated 6.6 and 9.9 times more Pb in leaves and roots respectively, compared to radish, under Pb supply which encouraged the growth of both plants. The intercropping under Pb supply induced a three-fold decrease of radish root biomass and 7.8-fold decrease of Pb content. Changes in plant antioxidant activity were recorded only under Pb supply and were not related to radish-wormwood interaction: the leaf phenolics content and antioxidant activity displayed 1.4- and 2- fold increases, respectively, in radish, and 1.4- and 1.6-fold decreases in wormwood. Synchronous changes in elemental composition of wormwood and radish in intercropping conditions, without or under Pb supply, suggest the significance of this phenomenon in plants interaction and arise high prospects of A. scoparia utilization to tackle weeds and soil Pb pollution

Bacterial siderophore improves nutrient uptake, leaf physiochemical characteristics, and grain yield of cumin (Cuminum cyminum L.) ecotypes

Cumin is one of the most popular herbs that is used widely as a spice and medicinal purposes. In Iran, cumin is mainly cultivated in high pH soils in arid regions where some elements such as iron (Fe) and zinc (Zn) cannot be adequately absorbed. Accordingly, we hypothesized that using chelating agents like bacterial siderophore could alleviate nutrient deficiency under such conditions. Cumin ecotypes (Sabzevar, Torbat-e-Jam, Taibad, and Shiraz) and bacterial siderophore treatments (control, seed priming, foliar spray, and seed priming + foliar spray (combined); 0.2%) were considered as the experimental factors. The application of siderophore increased the concentration of Fe, Zn, and nitrogen (N) in leaves and grains compared with the control. The highest leaf Fe concentration was observed when the combined treatment was applied. Sabzevar showed the highest grain Fe and Zn concentrations by 110 and 50%, respectively, over the control in the combined treatment. The highest grain yield was obtained from the combined-treated Taibad plants by a 28% increase over the control. Compared with the control, essential oil yield was increased by 22% in the combined-treated plants. The results showed that the combined application of siderophore had a higher efficiency among the other treatments. Furthermore, bacterial siderophore could be usefully applied to improve physiological traits, nutrient absorption, and grain yield in cumin under an arid region.

Habitat conditions strongly affect macro- and microelement concentrations in Taraxacum microspecies growing on coastal meadows along a soil salinity gradient.

Wild greens can contribute to the human diet as an important source of essential nutrients and drugs. Since environmental factors, including soil properties, may affect the chemical composition of plants, it is necessary among others to assess various habitats in terms of their usefulness for wild plant harvesting and to study impact of environmental factors on the qualitative and quantitative chemical composition of plants. This study was aimed at (1) examining the mineral composition of leaves of three dandelion microspecies, (2) determining the variability of macro- and microelement concentrations in dandelion leaves from populations growing on salty, brackish and non-saline coastal meadows, and (3) assessing the effects of different habitat conditions on the mineral composition of dandelion leaves. It was hypothesized that dandelion microspecies would differ significantly in the mineral composition of leaves. It was also expected that soil conditions would significantly affect nutrient concentrations in dandelion leaves, with soil salinity being the most important factor that differentiated studied populations. Leaves of three dandelion microspecies (Taraxacum balticum, T. nordstedtii, T. haematicum) were harvested in Baltic costal grasslands, along the soil salinity gradient, to determine macro- and microelement concentrations. Soil samples collected in the closest vicinity of the harvested plants showed the study sites to differ significantly in their soil properties. Moderately saline and organic soils, rich in potassium (K), magnesium (Mg), and calcium (Ca), supported T. balticum. Moderately or weakly saline and non-saline, organic or mineral soils, with lower median values of K, Mg, and Ca, were typical of T. nordstedtii sites, while the lowest median values of all the soil properties studied were found for T. haematicum sites. Our results proved that dandelion microspecies differ significantly in the mineral composition of their leaves. The between-microspecies differences were significant for all the macroelements except magnesium and all the microelements except molybdenum. Most of the macro- and microelements in leaves of the dandelion microspecies correlated positively and significantly with the soil properties, the strongest correlations being found for soil salinity and the leaf Na, Mn, Ca, Fe, K and Zn contents, followed by soil pH and the leaf Na, Mn, Fe, K, Ca, Zn and Mg. Moreover, the impact of soil properties on the mineral contents in leaves of the dandelions we examined seems to be stronger than the genetic differences between dandelion microspecies. Results of our studies on mineral composition of dandelion leaves lend support to the contention that wild greens provide essential mineral nutrients to the diet. Coastal meadows, fed by the brackish water of the Baltic Sea and free of anthropogenic pollution, are a good habitat to collect wild greens from.

Post-harvest foliar-applied Fe(II)-sulfate promotes Fe nutrition of pear trees grown in calcareous soil

The effectiveness of post-harvest foliar-applied Fe(II)-sulfate was assessed and indices were tested for precocious prognosis of Fe-chlorosis in field-grown pear trees. In a commercial pear (Abbé Fétel/BA 29) orchard, Fe-induced chlorotic trees were sprayed in early autumn with a Fe(II)-sulfate heptahydrate solution and compared with water-sprayed control trees. Leaf Fe concentration was higher in senescent and abscised leaves of Fe-sprayed trees, indicating that Fe was taken up. However, phytotoxic symptoms occurred and leaves fell earlier than in untreated trees. Fe(II)-sulfate spray increased Fe concentration of flower buds and fruiting spur leaves as well as leaf Chl values. Yield was increased in sprayed trees by about 13%, mostly associated with a higher fruit number per tree rather than fruit size, indicating an improved fruit set. We hypothesize that a fraction of the absorbed Fe contributed to sustain Fe requirements of the newly formed organs as from growth resumption. Summer leaf SPAD readings were positively correlated with Fe concentration of flower buds, fruiting spur leaves and, in particular, with senescent and abscised leaves. Our findings suggest the effectiveness of the post-harvest foliarly applied Fe(II)-sulfate to improve Fe nutrition of pear trees the following season. Rather than inducing a temporary re-greening, our approach is based on the fact that high Fe-rates sprayed before leaf fall may contribute to increase Fe pools within perennial organs. We propose utilizing leaf Fe concentration of senesced and abscised leaves as a predictive tool for the diagnosis of the Fe-chlorosis occurrence in pear trees.

Selenium activates components of iron acquisition machinery in oilseed rape roots

Beneficial elements may stimulate plant growth by favoring the availability of essential nutrients for metabolic processes. This study addresses the still unexplored question whether the beneficial action of selenium (Se) on plants can be due to its interaction with iron (Fe). Oilseed rape (Brassica napus) plants were grown hydroponically without (–Se) or with 10 μM Na2SeO4 (+Se) and exposed to either Fe adequate (+Fe) or starvation (–Fe) treatments. Selenium enhanced leaf chlorophyll concentration, photochemical parameters and CO2 fixation. Although Se did not significantly increase total leaf Fe concentration, the concentration of cytoplasmic FeII pool was enhanced under –Fe + Se conditions. However, the most conspicuous Se effects occurred in Fe-deficient roots. Selenium upregulated both the root expression levels of genes encoding FERRIC-REDUCTION OXIDASE (FRO1) and the activity of FRO and exacerbated the stimulatory effect of –Fe on the exudation rate of organic acids and phenolic compounds. Both –Se and + Se plants used FeIIIEDTA in similar way, while only +Se plants were able to take advantage of the sparingly soluble Fe(OH)3. In order to explore the mechanism of Se action, we recorded higher endogenous level of NO and upregulation of ETHYLENE RESPONSE FACTOR 2 (ERF2) by Se irrespective of Fe conditions. Our results show that Se augments root machinery for Fe acquisition mainly through activation of Fe signaling components.

Early Season Foliar Iron Fertilization Increases Fruit Yield and Quality in Pomegranate

Early season foliar fertilization with different nutrients is a promising tool in pomegranate grown in poor, high pH soils. The effects of foliar fertilization with FeSO4 and the synthetic chelate Fe(III)-EDDHA (Fe(III)-ethylendiaminedi(o-hydroxyphenylacetate)) on fruit yield and physicochemical characteristics were assessed in a two-season field trial. Fertilizers were sprayed at full bloom and one month later, using Fe concentrations of 1.3 and 2.6 mM for FeSO4 and 1.1 and 2.1 mM for the Fe-chelate. Both doses of FeSO4 and the higher chelate dose increased leaf Fe concentrations and fruit yield, with the best results being observed with 2.6 mM FeSO4 (20–31% increases in yield). On the other hand, leaf N, P, K, Ca, and Mn concentrations were not affected by foliar Fe fertilization. The only treatment that increased the number of fruits per tree, aril juice content and juice total soluble solids and decreased juice total acidity in both seasons was 2.6 mM FeSO4. Both FeSO4 doses caused consistent increases in the maturity index and total sugars in juice, along with minor decreases in juice total phenolic compounds. The antioxidant activity in juice was slightly decreased by 2.6 mM FeSO4. In conclusion, early season foliar Fe fertilization had positive effects on pomegranate yield and quality, with FeSO4 being better than Fe(III)-EDDHA.

EFFECT OF CALCIUM AND BORON AS FOLIAR SPRAY ON “LE CONTE” PEAR TREES PRODUCTIVITY

at El-Kanater Horticultural Research Station to investigate the effect of foliar application of Ca (NO3)2 (1 and 2 % ) and borax (100 and 200 ppm) as individual or in combined on yield, leaf mineral content and fruit characteristics. The results obtained that, the highest fruit length, size, and diameter as well as fruit weight (g), fruit yield/ tree (kg) and fruit yield as ton/ fed. were recorded when pear tree was sprayed with 1or 2 % calcium nitrate + 100 or 200 ppm borax compared with both calcium and borax alone. Fruit firmness and acidity were increased by foliar spray of combined treatment calcium 100 or 200 ppm borax + 1 or 2 % Ca (NO3)2 compared to control. Spraying1 or 2% Ca (NO3)2 alone gave the highest significant value of N % for pear leaves meanwhile P % was improved significantly using 200 ppm borax + 2% Ca (NO3)2. Also, K, Ca and Mg % were increased significantly with spraying 200 ppm borax+2 % Ca (NO3)2. In most cases, leaf Fe and Zn contents were increased significantly by combined treatment of 100 or 200 ppm borax + 2 % Ca (NO3)2or 100 ppm borax alone .

Çilek Meyve ve Yaprak Mikro Besin Elementlerinin Farklı Sulama Seviyeleri ile Biyo-aktivatör Uygulamasına Tepkileri

In this study, the effects of different irrigation levels (IR125, IR100, IR75 and IR50) and bio-activator application on micronutrient (Fe, Cu, Mn and Zn) concentrations of fruits and leaves of cultivar Rubygem were investigated during the active harvest period of 2015-2016. As a result of the study, which carried out in Çukurova University trial area, it was determined that different irrigation levels caused significant differences in all micronutrient element concentrations examined in leaves, although it caused significant changes only in Fe and Zn concentrations in fruits. IR50 application was found to be in the highest importance group in leaf Fe, fruit Fe and Zn concentrations, while IR75 application was found to be in the same importance group with IR100 for Zn, Cu and Mn concentrations according to both fruit and leaf analysis results. In the experiment, it was determined that bio-activator applications significantly increased Zn, Cu and Fe concentrations of both leaves and fruits. Therefore, it is thought that bio-activator application can be an important strategy for strawberry cultivation and at the same time, 25% restricted irrigation can be considered as an alternative method to full irrigation in water shortage areas.