BACKGROUND
Iodine deficiency is an environmental health problem affecting one-third of the global population. An iodine biofortification hydroponic experiment was conducted to explore the iodide and iodate uptake characteristics of strawberry plants, to measure the dosage effects of iodine on plant growth and to evaluate the influence of I- or IO3- application on fruit quality.


RESULTS
After biofortification, the iodine contents of the fresh strawberry fruits were 600-4000 µg kg-1 , covering the WHO dietary iodine allowance of 150 µg · day-1 for adults. The iodine uptake of the strawberry plants increased with increasing I- or IO3- concentration of the culture solution. At the same iodine concentration, the iodate uptakes of various plant organs under I- treatments were apparently more than those under IO3- treatments. Low-level exogenous iodine (I- ≤ 0.25 mg L-1 or IO3- ≤ 0.50 mg L-1 ) not only promoted plant growth and increased biomass per plant, but also improved fruit quality by enhancing the vitamin C and soluble sugar contents of the strawberry fruits. Nevertheless, excessive exogenous iodine inhibited plant growth and reduced biomass per plant. IO3- uptake apparently increased the total acidity and nitrate content of the fruits, reducing the quality of the strawberry fruits. Conversely, I- uptake obviously decreased the total acidity and nitrate content of the strawberry fruits, improving the fruit quality.


CONCLUSION
The strawberry can be used as a target crop for iodine biofortification. Furthermore, applying an appropriate dose of KI can improve the fruit quality of the strawberry plants. © 2016 Society of Chemical Industry.

Iodide and iodate effects on the growth and fruit quality of strawberry

A human’s diet should be diverse and rich in vitamins, macro- and microelements essential for the proper functioning of the human body. Globally, a high percentage of the human population suffers from malnutrition, deficiencies of nutrients and vitamins also known as the problem of hidden hunger. This problem it is not only common in poor countries, but also occurs in developed countries. Iodine is a nutrient crucial for the proper functioning of the human and animal body. For plants, it is referred to as a beneficial element or even a microelement. The design of the biofortification experiment was determined on the basis of the interaction of iodine and vanadium (synergistic interaction in marine algae), where vanadium-dependent iodoperoxidase catalyzes apoplastic oxidation of iodine, resulting in high efficiency of iodine uptake and accumulation in brown algae (Laminaria digitate). Three independent experiments (Exp.) were carried out with the foliar application of vanadium (V) and iodine (I) compounds. The main differences between the experiments with the adapted proper corn biofortification method were the different application stage between the individual experiments, the application intervals and the dose of the iodine–vanadium compound. In each experiment, the accumulation of iodine and vanadium in the grain was several times lower than in the leaves. The combination iodine and vanadium significantly increased the accumulation of iodine in the grain in the case of applying V with inorganic iodine compounds, and a decrease in the accumulation of I after applying V with organic iodine compound —especially in Exp. No. 3. In grain, the highest content of I−, IO3− was in combination with the application of 2-iodobenzoic acid (products of its metabolism). In most of the tested combinations, vanadium stimulated the accumulation/synthesis of exogenous/endogenous 5-iodosalicylic acid (5ISA) and 2-iodobenzoic acid (2IBeA), respectively, and decreased the content of 2,3,5-triiodobenzoic acid (2,3,5-triIBeA) in leaves and grains. The tested compounds I and V and the combinations of their application had a diversified effect on the vitamin C content in the grains. Vanadium in the lower dose of 0.1 µM significantly increased the sugar content in the grain.

/pdf/synthesis-of-organic-iodine-compounds-in-sweetcorn-under-the-c9xsbv3m.pdf

Synthesis of Organic Iodine Compounds in Sweetcorn under the Influence of Exogenous Foliar Application of Iodine and Vanadium

This study aimed to determine the use of selected vegetables (pumpkin, cauliflower, broccoli, carrot) as carriers of potassium iodide (KI) and potassium iodate (KIO3) by determining changes in iodine content under various conditions of impregnation as the degree of hydration, impregnated sample temperature, and impregnation time. The influence of these conditions on iodine contents in vegetables after their fortification and storage (21 °C/230 days) was analyzed. The results showed that all selected vegetables could be efficient iodine carriers. However, the conditions of the impregnation process are crucial for fortification efficiency, particularly the degree of hydration and the temperature of the impregnated samples before drying. The results showed that the lowest iodine content was in samples fortified at 4 °C and 1:4 hydration. On the other hand, the highest reproducibility of iodine was for the following fortification conditions: temperature of −76 °C and hydration of 1:1. The studies confirmed the higher stability of iodine in KIO3 form compared to KI. To increase recovery of the introduced iodine in the product after drying, using the conditioning step at 4 °C is not recommended. We recommend freezing vegetables immediately after the impregnation process

/pdf/the-selection-of-the-optimal-impregnation-conditions-of-3ivws9n6.pdf

The Selection of the Optimal Impregnation Conditions of Vegetable Matrices with Iodine

The horticultural sector is seeking innovative and sustainable agronomic practices which could lead to enhanced yield and product quality. Currently, plant biofortification is recognized as a valuable technique to improve microelement concentrations in plant tissues. Among trace elements, iodine (I) is an essential microelement for human nutrition. Concomitantly, the application of biostimulants may improve overall plant production and quality traits. With the above background in mind, an experiment was designed with the aim of assessing the interactive impact of a seaweed extract-based biostimulant (SwE) (0 mL L−1 (served as control) or 3 mL L−1 (optimal dosage)) and 0, 100, 300, or 600 mg L−1 I on the growth parameters, yield, fruit quality, minerals, and functional characteristics of the tunnel-grown “Savana” strawberry. SwE foliar application improved the plant growth-related traits, total and marketable yield, fruit color parameters, soluble solids content, nitrogen (N), potassium (K), and magnesium (Mg) fruit concentrations. Furthermore, an enhancement in the fruit dry matter content, ascorbic acid, and I concentration in fruits was detected when the SwE supply interacted with a mild I dose (100 or 300 mg L−1). The research underlined that combining SwE application and I biofortification increased the strawberry yield and quality and enhanced the plant nutritional status variation, thereby, determining a boosted strawberry I tolerance.

/pdf/iodine-biofortification-and-seaweed-extract-based-13yhob05.pdf

Iodine Biofortification and Seaweed Extract-Based Biostimulant Supply Interactively Drive the Yield, Quality, and Functional Traits in Strawberry Fruits

Balanced use of micronutrients in soils is essential for optimized nutrient use efficiency, environmental conservation and long-term sustainability of agro-ecological systems. As a result, maintaining correct micronutrient levels in the soil is essential not only to meet plant needs and maintain agricultural productivity but also to avoid nutrient build-up. The present study aimed to investigate the effect of micronutrient application on the yield and sucrose content expressed as the polarization of sugar cane juice (POL%) under field conditions. There were seven treatments, viz. T0 = No micronutrient application (control); T1 = ZnSO4 at the rate of 30 kg ha−1; T2 = CuSO4 at the rate of 10 kg ha−1; T3 = FeSO4 at the rate of 30 kg ha−1; T4 = borax at the rate of 2 kg ha−1; T5 = half dose of ZnSO4, CuSO4, FeSO4 and borax at the rate of 15, 5, 15 and 1 kg ha−1 and T6 = full dose of ZnSO4, CuSO4, FeSO4 and borax at the rate of 30, 10, 30 and 2 kg ha−1, arranged in randomized complete block design in triplicate. With the application of ZnSO4 at 30 kg ha−1 along with recommended doses of NPK, 30% more income was generated as compared with the control. Fist plant and ratoon crop yields were 19.08% and 22.03% higher, respectively, than in the control. Similarly, Zn application resulted in 5.91% and 8.64% greater sucrose contents (POL%) in plant and ratoon crops, respectively, when compared with the control. The application of ZnSO4 at the rate of 30 kg ha−1 along with recommended doses of NPK had a significant impact on the yield and sucrose contents of sugarcane.

/pdf/balanced-use-of-zn-cu-fe-and-b-improves-the-yield-and-1ywob6h6.pdf

Balanced Use of Zn, Cu, Fe, and B Improves the Yield and Sucrose Contents of Sugarcane Juice Cultivated in Sandy Clay Loam Soil

Around the world, maize cultivation is an essential part of food systems for humans and animals. Effective reactions against the occurrence of diseases related to the deficiency of elements in the human diet are related to the biofortification of plant species of broad importance, including maize. The enrichment of maize with iodine is difficult due to the poor transport of this element to the plant’s generative organs. In marine algae, vanadium is part of the structure of the enzyme iodine-dependent peroxidase (vHIPO) that catalyzes the uptake of cellular iodine (I) and its volatilization as I2. The relationship between iodine and vanadium in higher plants, however, is not well-known. The aim of this research was to determine the effect of vanadium fertilization and the interactions of organic and inorganic iodine compounds with vanadium under soil application. In the pot experiment, NH4VO3 was applied to the soil in two doses of 0.1 and 1 μmol·dm−3 both separately and in combination, with the following iodine compounds: 5-iodosalicylic acid (5-ISA), 2-iodobenzoic acid (2-IBeA), potassium iodide (KI), and potassium iodate (KIO3). The iodine compounds were also applied independently to vanadium, while in the control combination, fertilization was performed without I and V. Iodine compounds were applied with doses calculated using the molar mass of this element (i.e., 10 μmol·dm−3 I). The highest level of iodine accumulation in grains (regardless of fertilization with V) was obtained after the application of organic compounds 5ISA and 2IBeA. A lower dose of vanadium (0.1 μmol·dm−3) in combination with KI and KIO3 increased the accumulation of iodine in leaves, roots, and grains compared to the combination without the additional application of vanadium. The combined application of vanadium in both doses with 2-IBeA most effectively stimulated the transport and accumulation of iodine to the maize grain. Under the combined application of 5-ISA and vanadium (10 μmol·dm−3), we observed the stimulating effect of this organic iodine compound on the accumulation of vanadium in the roots as well as the antagonistic effect of vanadium in combination with 5-ISA on the accumulation of iodine in the roots, leaves, and maize grain. Vanadium accumulated mainly in the roots, where the content of this element increased proportionally to its dose. The soil application of 5-ISA increased the total sugar content and vitamin C content in the grain.

Dominik Grzanka

Papers

Biofortification of Sweetcorn with Iodine: Interaction of Organic and Inorganic Forms of Iodine Combined with Vanadium

Synthesis of Organic Iodine Compounds in Sweetcorn under the Influence of Exogenous Foliar Application of Iodine and Vanadium