Combined biofortification of carrot with iodine and selenium.

The aim of a three-year study was to assess the effect of combined biofortification with I and Se in carrot. Four cultivars ('Askona' F1, 'Samba' F1, 'Kazan' F1 and 'White Satin') were grown in soil fertilized with KI (4 kg I ha-1) and Na2SeO4 (0.25 kg Se ha-1). The I + Se fertilization did not affect yield but the plants of all cultivars accumulated both elements in leaves and roots. On average, the I and Se contents in roots increased 7.7-times for I and 4.9-times for Se as well as the average I:Se molar ratio was 0.28:1. The contents of both elements in roots remained well below the hazard threshold thus the intake of 100 g of biofortified carrot would substantially cover the RDA for I and Se. The changes in chemical composition of roots (nitrates, phenolic compounds, sugars, carotenoids, macro-, microelements and cadmium) were rather year-dependent than affected by the applied I + Se fertilization.

Biofortification of Six Varieties of Lettuce (Lactuca sativa L.) With Iodine and Selenium in Combination With the Application of Salicylic Acid.

The agrotechnical methods of biofortification of plants, i.e., enriching them in iodine (I) and selenium (Se) could be effective methods to enrich food products in these elements. The advantage of agrotechnical methods of biofortification is the incorporation of elements in organic compounds in plants; therefore, they have better health-promoting properties than pure technical salts. Two-year studies were conducted in a greenhouse with hydroponic cultivation of three botanical varieties of lettuce in an NFT (nutrient film technique) system: two cultivars butterhead lettuces (abb. BUTL) 'Cud Voorburgu' and 'Zimujaca,' two cultivars iceberg lettuces (abb. ICEL) 'Maugli' and 'Królowa lata' (all this four cultivars are classified as Lactuca sativa L. var. capitata) as well two cultivars Lactuca sativa L. var. crispa L. cultivars (abb. REDL) 'Lollo rossa' and 'Redin' having little red leaves. The study included the application of I (as KIO3), Se (as Na2SeO3), and SA into the nutrient solution. The tested treatments were as follows: (1) control, (2) I+Se, (3) I+Se+0.1 mg SA dm-3, (4) I+Se+1.0 mg SA dm-3, and (5) I+Se+10.0 mg SA dm-3. KIO3 was used at a dose of 5 mg I dm-3, while Na2SeO3 was 0.5 mg Se dm-3. Regardless of the kind of the applied compound, the highest biomass of heads was produced by the REDL 'Redin' variety. Furthermore, this variety, as the only one in six varieties tested, reacted with the decrease in yield to the application of I+Se and I+Se+three concentrations of SA. In the heads of all cultivars, the level of I accumulation was 10-30 times higher than of Se. The level of I accumulation formed the following order: REDL 'Lollo rossa' > REDL 'Redin' = BUTL 'Cud Voorburgu' > BUTL 'Zimujaca' > ICEL 'Maugli' > ICEL 'Królowa lata'. The order of Se content in leaves was as follows: REDL 'Redin' = BUTL 'Cud Voorburgu' > REDL 'Lollo rossa' > ICEL 'Maugli' > BUTL 'Zimujaca' > ICEL 'Królowa lata'. The obtained results indicate that the introduction of SA to the nutrient solutions in hydroponic systems may allow an improve the effectiveness of - biofortification.

Organic iodine supply affects tomato plants differently than inorganic iodine.

Iodine is a beneficial element for humans but very lowly represented in our diet. Iodine-enriched vegetables could boost the iodine content in the food chain. Despite being a beneficial element for plants, little is known about the effect of different iodine forms on plant growth. This work analyses the effect of uptake of mineral (KI) and organoiodine (5-iodosalicylic acid, 5-ISA; 3,5-diiodosalicylic acid, 3,5-di-ISA; 2-iodobenzoic acid, 2-IBeA; 4-iodobenzoic acid, 4-IBeA) compounds on tomato plants at an early stage of vegetative growth. As many organoiodine compounds are derived from salicylic (SA) and benzoic acids (BeA), treatments with I, SA and BeA in various treatments were realized and the influence of tested compounds on plant growth was analyzed. Iodine content was measured, as well as expression of key genes involved in I and SA metabolism. Organoiodine compounds accumulated mainly in roots whereas iodine accumulated in the upper parts when given as KI. The shoot system had 5, 12 and 25 times higher iodine content after KI treatment than after 4-IBeA, 5-ISA and 2-IBeA, or 3,5-diISA treatments, respectively. A toxic effect on plants was observed only for 3,5-diISA and 4-IBeA. The expression levels of a gene related to iodine metabolism (HMT, halide ion methylotransferase), a gene responsible for SA methylation in leaves (SAMT) and a gene related to SA catabolism (S3H, salicylic acid 3-hydroxylase) were modified differently depending on the iodine source. Overall, our data point out to a difference in plant uptake, transport of iodine in tomato plants based on the form of iodine compound.

Iodine and Selenium Biofortification with Additional Application of Salicylic Acid Affects Yield, Selected Molecular Parameters and Chemical Composition of Lettuce Plants (Lactuca sativa L. var. capitata).

Iodine (I) and selenium (Se) are included in the group of beneficial elements. They both play important roles in humans and other animals, particularly in the regulation of thyroid functioning. A substantial percentage of people around the world suffer from health disorders related to the deficiency of these elements in the diet. Salicylic acid (SA) is a compound similar to phytohormones and is known to improve the efficiency of I biofortification of plants. The influence of SA on Se enrichment of plants has not, however, been recognized together with its effect on simultaneous application of I and Se to plants. Two-year studies (2014-2015) were conducted in a greenhouse with hydroponic cultivation of lettuce in an NFT (nutrient film technique) system. They included the application of I (as KIO3), Se (as Na2SeO3) and SA into the nutrient solution. KIO3 was used at a dose of 5 mg I⋅dm-3 (i.e., 39.4 µM I), while Na2SeO3 was 0.5 mg Se⋅dm-3 (i.e., 6.3 µM Se). SA was introduced at three doses: 0.1, 1.0, and 10.0 mg⋅dm-3 nutrient solutions, equivalent to 0.724, 7.24, and 72.4 µM SA, respectively. The tested combinations were as follows: (1) control, (2) I + Se, (3) I + Se + 0.1 mg SA⋅dm-3, (4) I + Se + 1.0 mg SA⋅dm-3 and (5) I + Se + 10.0 mg SA⋅dm-3. The applied treatments had no significant impact on lettuce biomass (leaves and roots). Depending on the dose, a diverse influence of SA was noted with respect to the efficiency of I and Se biofortification; chemical composition of leaves; and mineral nutrition of lettuce plants, including the content of macro- and microelements and selenocysteine methyltransferase (SMT) gene expression. SA application at all tested doses comparably increased the level of selenomethionine (SeMet) and decreased the content of SA in leaves.

The Iodine Content in Urine, Faeces and Selected Organs of Rats Fed Lettuce Biofortified with Iodine Through Foliar Application.

Iodine is an essential trace element for humans. Foliar application of micronutrients is successfully used in order to increase the concentration of essential elements in vegetables. The aim of this study was to evaluate the iodine absorption in the rat organism fed foliar biofortified lettuce. The presented study was consisted of the vegetative and animal experiment. In the vegetative experiment with lettuce, two combinations of foliar application were used: (1) control-without iodine application and (2) iodine application in the potassium iodide (KI) form. In the animal experiment, Wistar rats were divided to four groups, which received one of four diets: (1) C-control diet containing iodine in the KI form, (2) D-diet deficient in iodine, (3) D + BL-diet containing biofortified lettuce, and (4) D + CL-diet containing control lettuce (as the only source of iodine in diet, respectively). The diets contained 0.260, 0.060, 0.254 and 0.075 mg I/kg, respectively. In order to determine the iodine absorption in the rat organisms, the content of this trace element was measured in urine, faeces and in selected organs with the use of the ICP-OES technique. Foliar application of the KI increased the content of iodine in lettuce. The rats from the D + BL group excreted significantly less iodine in their urine and faeces and also accumulated more iodine in the organs than the rats from the C group. Iodine with biofortified lettuce was much bioavailable for rodents than iodine from control diet. Biofortified lettuce can be a source of iodine in a diet of human and can improve iodine nutrition.

Quality of fresh and stored carrots depending on iodine and nitrogen fertilization.

INTRODUCTION: Iodine is an important mineral nutrient essential for a proper functioning of human and animal organism. Despite current programmes of iodine prophylaxis (mainly based on salt iodization) approximately 30-38% of human population has insufficient iodine intake. Crop plants can become an efficient vector of this element in the food chain. Iodine is not a nutrient for plants. For that reason, in addition to determining the possibility of increasing iodine content in crop plant it is necessary to describe its impact on yield quality. The aim of the study was to analyze the influence of soil fertilization with iodine and nitrogen on the quality of carrot roots and its storage ability. METHODS: In 2008-2010 the field study with carrot cv. 'Kazan F1' was conducted. A differential soil fertilization with iodine (in the form of I(-) or IO3(-)) and nitrogen (as NO3(-) or NH4(+)) was applied in the experiment: (1) control without N and I, (2) KI application without N, (3) KIO3 application without N, (4) KI+Ca(NO3)2, (5) KIO3+Ca(NO3)2, (6) KI+(NH4)2SO4 and (7) KIO3+(NH4)2SO4. The experiment was arranged in a split-plot design. Iodine (in both forms) was applied pre-sowing in a dose of 2 kg I ha(-1). Nitrogen in the form of Ca(NO3)2 and (NH4)2SO4 was introduced pre-sowing and as a top dressing, each dose of 100 kg N ha(-1). RESULTS AND DISCUSSION: A diverse, statistically significant influence of tested factors on the activity of free radical-scavenging (DPPH) and the content of: dry matter, glucose, fructose, sucrose, total soluble sugars, soluble solids - Brix %, phenolic compounds, phenylpropanoids, flavonols, anthocyanins and carotenoids was noted in carrot roots directly after the harvest as well as at the end of four-month storage. Iodine applied with relatively high doses of nitrogen decreased the quality of fresh carrot. After storage, opposite relations were noted for tested combinations (with I and N application) with respect to carrot quality when compared to results obtained after the harvest. The lowest storage ability was found for carrot treated with KI without N. Obtained results directly suggest the need for developing individual agronomic rules for iodine biofortification of carrot for: (a) consumption and/or processing directly after the harvest and (b) long-term storage.