Foliar Application Of Se Research Articles

Foliar application of selenium increases fertility and grain yield in bread wheat under contrasting water availability regimes

The study was conducted to assess whether selenium (Se) application modulates fertility to alter grain yield in bread wheat grown under different moisture regimes. Seeds of wheat cultivar Millat-2011 were sown in the plots using a randomized complete block design with three replicates per treatment. After germination, the plants were exposed to six moisture regimes, viz. no irrigation after germination, irrigation at boot stage, irrigations at boot and grain-filling stages, irrigations at crown root, boot and grain-filling stages, irrigations at crown root, boot, heading and grain-filling stages and irrigations at crown root, stem elongation, boot, heading and grain-filling stages. At the heading stage, foliar spray of sodium selenate (0, 2 and 4 mg Se L−1) was done. Withholding water at early growth stages significantly increased oxidative stress and decreased growth and grain yield. Irrespective of moisture regimes, foliar application of Se (2 mg L−1) decreased oxidative stress, modulated photosynthetic pigments and fertility and increased grain yield in wheat. The Se-mediated increase in grain yield was attributed to the increase in chlorophyll and ascorbic acid contents and fertility coupled with decrease of oxidative stress under different moisture regimes. The results could be helpful to manage wheat production in the semi-arid environments.

Separate and combined effects of silicon and selenium on salt tolerance of wheat plants

Soil salinity is the leading global abiotic stress which limits agricultural production with an annual increment of 10%. Therefore; a pot experiment was conducted with the aim to alleviate the salinity effects on wheat seedlings through exogenous application of silicon (Si) and selenium (Se). Treatments included in the study were viz. (Ck) control (no NaCl nor Si and Se added), only salinity (50 mM NaCl), salinity + Si (50 mM NaCl with 40 mM Si), salinity + Se (50 mM NaCl with 40 mM Se) and salinity + Si + Se (50 mM NaCl + 40 mM Si + 40 mM Si). The salt stress impaired the growth (root and shoot dry weight, root: shoot ratio, seedlings biomass), water relations, photosynthetic attributes, transpiration rate and chlorophyll contents of wheat seedlings. Nonetheless, the foliar application of Si and Se alone and in combination improved the growth, water relations, photosynthetic attributes, transpiration rate and chlorophyll contents of wheat seedlings under stressed conditions. Moreover, an increase in antioxidant enzyme activity and accumulation of osmo-protectants (proline, soluble protein and soluble sugar) was noted under stressed conditions, which was more pronounced in wheat seedling which experienced combined application of Si and Se. To conclude that, foliar application of Si alone mitigated the adverse effect of salinity, while the combined application of Si and Se was proved to be even more effective in alleviating the toxic effects of salinity stress on wheat seedlings.

Effects of foliar dressing of selenite and silicate alone or combined with different soil ameliorants on the accumulation of As and Cd and antioxidant system in Brassica campestris

This study was conducted to investigate the possibility of using a combined technology to synchronously reduce As and Cd accumulation in the edible parts of Brassica campestris. The results showed that a foliar application of selenite (Se) and silicon (Si) combined with soil ameliorants (including Ca-Mg-P fertilizer, sodium silicate and red mud) showed limited effects on the growth of B. campestris. The As concentration in the leaves of B. campestris in all treatments was below the Chinese safety standard. When sodium silicate and Ca-Mg-P fertilizer were added to the soil, the additional foliar application of Se and Si could in some cases help further reduce the concentrations of As and Cd in the leaves of B. campestris. However, when red mud was applied to the soil, the foliar application of Se and Si enhanced the Cd concentration in the leaves of B. campestris. In most cases, high levels of soil ameliorants plus foliar application of Se and Si significantly enhanced the As concentrations in both the soil solution and the roots of B. campestris but reduced the soil solution Cd concentration and the leaf As concentration. Most of the treatments reduced the thiobarbituric acid reactive substances (TBARS) concentration in the leaves of B. campestris, and the foliar application of Se and Si helped the soil ameliorants alleviate the oxidative stress resulting from As and Cd exposure. In this study, several treatments significantly increased the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). However, the enzymes peroxidase (POD) and catalase (CAT) were not induced by most treatments. In summary, the combined treatment of 1gkg−1 Ca-Mg-P fertilizer plus foliar spraying 2mmolL−1 sodium selenite was most effective in reducing the Cd concentration and a rather strong ability to reduce the As concentration and trigger the activities of SOD and APX in the leaves of B. campestris.

Effects of Selenium Application on Plant Growth and Some Quality Parameters in Peanut (Arachis hypogaea).

Selenium (Se) is an essential plant micronutrient and has been repetedly shown to enhance crop growth and crop tolerance to abiotic stresses when applied in trace amounts. However, physiological responses of different plants vary significantly to the Se fertilizer application. The aim of this study was to investigate the effect of Se application on yield and quality parameters of peanut under field conditions. A pot experiment was conducted where Se fertilizer was applied (i) To soil at 5 different doses, (ii) As folier fertilizer or (iii) Via seed soaking at 4 different doses. Two years field experiments were conducted under East Mediterranean conditions of Turkey. The yields were significantly increased by all types of Se applications. The highest yield (6130 kg ha-1) was obtained from foliar applications made 40 days after flowering. Increasing doses of Se increased 100 grain weight but oil, protein and nitrogen content of grains were not affected. Two years experiment clearly showed that external Se supply to peanut (all methods tested) increased yield formation in East Mediterranean conditions of Turkey. Here, particularly foliar application (3% sodium selenite) of Se 40 after flowering seems to be most effective way for its application.

Effect of humic acid-based amendments with foliar application of Zn and Se on Cd accumulation in tobacco

The smoke of tobacco is a major source of exposure to Cd in humans and therefore it is urgent to find a way to a method to reduce Cd accumulation in tobacco. A four-month tobacco pot experiment was conducted to investigate the effects of two base treatments (humic acid-based amendments) and two foliar treatments (Zn and Se) on Cd uptake by tobacco. The results showed that Cd in tobacco was mainly transferred into leaves, which could be significantly reduced by both applied amendments. The Cd contents in leaves were reduced by up to 67%. Foliar Zn alone significantly decreased Cd contents in leaves while foliar Se slightly increased them. When base and foliar treatments were combined, base treatments had dominant effects but those of foliar treatments were not distinct. The applied amendments did reduce Cd contents in all the parts of tobacco and the translocation into leaves and they were more effective than foliar Zn and Se.

Efficiency of foliar selenium application on oilseed rape (Brassica napus L.) as influenced by rainfall and soil characteristics

ABSTRACTThe Czech Republic is characterized by a low Se soil content, resulting in Se deficiency in crops, humans, and animals. This study investigated the response of oilseed rape to foliar application of selenate solution in a microscale field experiment conducted at two locations differing in soil and climatic conditions but with comparable total Se contents. Sodium selenate (Na2SeO4) was applied at two rates (25 and 50 g Se ha−1). The potential effect of Se application on the uptake of essential elements was also evaluated. The foliar Se application resulted in an effective stepwise increase in the Se contents of all the plant components studied (leaves > stems > roots > siliques ~ seeds), as expected. No significant influence of Se fortification on the other investigated macro- and microelements was observed. However, the soil and climatic conditions influenced the Se uptake, such that a higher Se content was observed in plants grown in the most acidic location (Cambisol soil) that had a higher oxidizable carbon content and higher average annual rainfall compared to the less acidic location (Luvisol soil). These observations indicated the necessity to optimize the Se application for the particular soil and climatic conditions to achieve a maximum biofortification effect.

Selenium in Soil-Crop-Animal System: A Holistic Perspective to Manage Animal and Human Health

Selenium (Se) dependent enzymes play important roles in physiological functions such as thyroid hormone metabolism, strengthens anti-oxidant defense system and immune system. However, about 800 million people worldwide are believed to be deficient in Se which is attributed to low Se levels in the soil. This is because Se in plant and animal products in human diet depends upon the available Se in the soil. Deficiency of Se can be prevented or treated by adequate dietary intake or through direct supplementation. There have been reports that patients with dilated cardiomyopathy, HIV viral loads and cancer have responded to Se supplementation. However, food fortification has been found to be more efficient than supplementation. Both agronomic biofortification and genetic biofortification have been used to increase Se content of food crops and animal products. Genetic engineering makes use of key genes of Se hyperaccumulators to increase Se accumulating potential of food crops. Agronomic biofortification increases Se content of food crops by adding Se rich fertilizers to the soil or foliar application of Se. Selenium can also be added to animal diets or feedstuff to increase Se content of meat, eggs, and milk. Although inorganic forms of Se are approved as feed additives, they are less efficient than organic sources such as selenomethionine (SeMet) which is the dominant form in plants and animals. Animal products have been found to have higher Se content than plant products with fish having the highest Se content. Fruits and vegetables have a low content of Se probably because of their low protein content. Recommendations for dietary intake of Se vary with country, age and sex. There are concerns that the present recommended Se daily allowance may not be adequate due to discovery of other selenoenzymes with higher Se requirements than gluthathione peroxidase. There may be a need to review the current recommended daily allowance for Se in order to improve human health.

Combined foliar selenium and zinc biofortification in field pea (Pisum sativum): accumulation and bioavailability in raw and cooked grains

Millions of people have an inadequate intake of selenium (Se) and zinc (Zn), and foliar biofortification may minimise these problems. To evaluate the efficacy of combined foliar Se and Zn fertilisation in field pea (Pisum sativum L.) grains, foliar Se and Zn applications were tested individually and in all combinations (0, 0.03% or 0.06% (w/v) NaSeO4, and 0, 0.25% or 0.5% (w/v) ZnSO4.7H2O) at early grain filling. Plant growth was not influenced by any of the treatments. There was a positive relationship between total Se or Zn concentration in raw or cooked grains and respective Se or Zn application dose. Grain Zn accumulation was positively influenced by the combined application of Se and Zn. Grain cooking caused a slight decrease in grain Se (by 7.4%) and Zn concentrations (by 19%); however, cooking enhanced Zn bioavailability. The consumption of 100 g of cooked, biofortified field peas would provide ~50% of recommended daily intake of Zn and 45% of Se. The present study successfully biofortified field peas with Se and Zn, with the combined foliar application of Se and Zn being the best option.

Possibility of selenium biofortification of winter wheat grain

The effect of foliar application of selenium (Se) fertilizers (sodium selenite and selenate) in two different Se doses (10 and 20 g/ha) on grain yield, Se content and mechanical and technological parameters of winter wheat grain was investigated in the field fertilization experiment. Foliar spray application of Se was applied at the growth stage of the 2<sup>nd</sup> node on the main stem (32 BBCH). Selenate foliar applications in dose 10 g Se per ha showed a significant increase of grain yield in comparison to control treatment without Se application. The mechanical and technological parameters of wheat grain were not significantly affected by both selenite and selenate foliar application. The average Se concentration was significantly lower in 2007/2008 (grain yield 8.72 t/ha) than 2006/2007 (yield 6.35 t/ha) growing season (0.133 versus 0.189 mg Se/kg dry matter). The grain Se absorption efficiency at foliar application of 10 and 20 g Se/ha of selenite and selenate were 1.35–1.45% and 13.24–15.14%, respectively.

Increasing Selenium and Yellow Pigment Concentrations in Foxtail Millet (Setaria italica L.) Grain with Foliar Application of Selenite.

Although addition of selenium (Se) is known to increase Se in crops, it is unclear whether exogenous Se is linked to nutritional and functional components in foxtail millet (Setaria italica L.). In this study, we examined the potential of increasing Se and yellow pigment (YP) in foxtail millet grain by foliar application of Se. Field experiments were conducted during the growing season of foxtail millet in 2013 and 2014 to assess the effects of foliar spray of sodium selenite (10-210gSeha(-1)) on the yield, Se uptake and accumulation, total YP, and microminerals in the grain. Average grain yields with Se application were 5.60 and 4.53tha(-1) in the 2years, showing no significant differences from the unfertilized control. However, grain Se concentration increased linearly with Se application rate, by 8.92 and 6.09μgkg(-1) in the 2years with application of 1gSeha(-1) (maximum grain recovery rates of Se fertilizer, 52 and 28%). Likewise, total grain YP concentration markedly increased by 0.038 and 0.031mgkg(-1) in the 2years with application of 1gSeha(-1). Grain Mn, Cu, Fe, and Zn concentrations were not significantly affected by Se application. This study indicated that foliar application of Se effectively and reliably increased the concentrations of Se and YP in foxtail millet grain without affecting the yield or mineral micronutrient concentrations. Thus, foliar-applied selenite has a significant potential to increase the concentrations of selenium and YP (putative lutein (Shen, J Cereal Sci 61:86-93, 2015; Abdel-Aal, Cereal Chem 79:455-457, 2002; Abdel-Aal, J Agric Food Chem 55:787-794, 2007)) of foxtail millet and, thus, the health benefits of this crop.

Mycorrhizal inoculation and/or selenium application affect post-harvest performance of snapdragon flowers

The effect of mycorrhizal inoculation and/or selenium (Se) application as possible agents to improve post-harvest performance of cut snapdragon (Antirrhinum majus L.) flowers had been studied. Rhizophagus intraradices was inoculated to half of plants at the seedling stage. One third of non-inoculated plants and one third of plants inoculated with R. intraradices were not supplied with Se. One third of non-inoculated and inoculated plants were foliar-sprayed with either 100 or 200 μg of seleninic acid per plant before flowering. Flowers were harvested at dawn, packed dry or placed in water and stored in darkness at 5 °C. Afterwards, the vase-life of cut flowers was evaluated. Plant growth and water parameters as well as photosynthetic pigments and organic solutes in leaves were determined at harvesting. The results showed that mycorrhizal inoculation improved plant height, length and basal diameter of flowering stems. In plants untreated with Se, mycorrhizal inoculation increased starch, phenolics, chlorophylls and carotenoids but decreased soluble sugars and proline in leaves. Mycorrhizal inoculation counteracted the reductions in carbohydrates, proline and proteins caused by Se in non-inoculated plants. Type of storage strongly influenced post-harvest performance of cut flowers, being dry storage the most beneficial for delaying senescence. In comparison with non-inoculated plants untreated with Se, neither mycorrhizal inoculation nor the foliar application of Se, alone or combined, prolonged the vase-life of cut flowers. High dose of Se decreased the vase-life of flowers from non-inoculated snapdragons and mycorrhizal inoculation counteracted this negative effect. Changes in water status and carbohydrate metabolism in plants inoculated or not with R. intraradices may have resulted in unusual development of flowering stems and post-harvest performance of flowers after spraying high dose of Se. Further research is needed to confirm this hypothesis.

Exogenously applied selenium reduces oxidative stress and induces heat tolerance in spring wheat

Heat stress (HS) is a worldwide threat to productivity of wheat, especially in arid and semiarid regions of the world. Earlier studies suggested the beneficial effects of selenium (Se) on the growth of some crop species grown under stressful environments. In the present study, we assessed whether Se application could increase antioxidative potential, and thus enhance tolerance to heat in wheat at the sensitive stage i.e., heading stage. At the heading stage, after foliar application of sodium selenate solutions (0, 2 and 4 mg Se L−1), the plants of wheat cultivars, namely Chakwal-97 (drought tolerant) and Faisalabad-08 (drought sensitive), were subjected to HS (38 ± 2 °C). The HS significantly altered antioxidative potential, affected growth, photosynthetic pigments and grain yield in both cultivars. Exogenous application of low (2 mg L−1) Se increased chlorophyll a and total chlorophyll contents and modulated the growth of wheat plants under HS. However, high concentration (4 mg L−1) of Se was much more effective in increasing grains per spike and grain yield in heat stressed plants of both wheat cultivars. Exogenous Se increased both enzymatic (catalase and ascorbate peroxidase activities) and non-enzymatic (carotenoids, anthocyanins and ascorbic acid contents) antioxidants while decreased oxidants (hydrogen peroxide and malondialdehyde contents) under HS in both wheat cultivars. In conclusion, foliar application of Se (4 mg L−1) was much more effective in mitigating the deleterious effects of HS on grain yield of wheat plants. The results suggested that Se-mediated up-regulation of antioxidative system (both enzymatic and non-enzymatic) helped the wheat plants to increase fertility, and hence avoid reduction of grain yield under HS.

Will selenium increase lentil (Lens culinaris Medik) yield and seed quality?

Lentil (Lens culinaris Medik), a nutritious traditional pulse crop, has been experiencing a declining area of production in South East Asia, due to lower yields, and marginal soils. The objective of this study was to determine whether selenium (Se) fertilization can increase lentil yield, productivity, and seed quality (both seed Se concentration and speciation). Selenium was provided to five lentil accessions as selenate or selenite by foliar or soil application at rates of 0, 10, 20, or 30 kg Se/ha and the resulting lentil biomass, grain yield, seed Se concentration, and Se speciation was determined. Seed Se concentration was measured using inductively coupled plasma optical emission spectrometry (ICP-OES) after acid digestion. Seed Se speciation was measured using ICP-mass spectrometry with a high performance liquid chromatography (ICP-MS-LC) system. Foliar application of Se significantly increased lentil biomass (5586 vs. 7361 kg/ha), grain yield (1732 vs. 2468 kg /ha), and seed Se concentrations (0.8 vs. 2.4 μg/g) compared to soil application. In general, both application methods and both forms of Se increased concentrations of organic Se forms (selenocysteine and selenomethionine) in lentil seeds. Not surprisingly, the high yielding CDC Redberry had the highest levels of biomass and grain yield of all varieties evaluated. Eston, ILL505, and CDC Robin had the greatest responses to Se fertilization with respect to both grain yield, seed Se concentration and speciation; thus, use of these varieties in areas with low-Se soils might require Se fertilization to reach yield potentials.

Agronomic biofortification of maize, soybean and groundnut with selenium in intercropping and sole cropping systems

Agronomic biofortification of staple food crops with micronutrients important for human nutrition, such as selenium (Se), is currently being advocated to address widespread deficiencies in the diets of populations in sub-Saharan Africa. Previous research has shown that there is likely to be widespread dietary Se deficiency in Malawi due to low concentration of Se in edible parts of the staple crops, such as maize (Zea mays L), on low-pH soils, but that this could be addressed through agronomic biofortification using Se-enriched fertilisers. Farmers often intercrop maize with legumes such as groundnut (Arachis hypogaea) and soybean (Glycine max). Therefore, a field study during the 2012/2013 cropping season examined the effect of foliar application of Se on its concentration in grains and stover of maize, soybean and groundnut grown as intercrops or sole crops at three sites in Malawi. Mean Se concentrations were highest in soybean seed, followed by groundnut seed and maize grain, both in plots with added Se and without. Application of 10 g ha-1 of Se increased Se concentration in maize grain by 8-fold, in groundnut seed by 9-fold and in soybean seed by 18-fold; thus universal adoption could increase estimated average dietary Se supply in Malawi from between 21 and 31 µg cap-1 d-1 to between 68 and 78 µg cap-1 d-1. Key words: Selenium, intercropping, food security, hidden hunger, biofortification, fertilizers, mineral micronutrient deficiencies.

Effect of selenium foliar spray on physiological and biochemical processes and chemical constituents of wheat under drought stress

Selenium (Se) is considered an essential micronutrient for humans, animals and plants due to its physiological and antioxidative properties. The positive role of Se in attenuation of drastic effects of various environmental stresses in plants is, however, still unclear and need to be explored. The present study aimed at investigating the physiological and biochemical changes induced by Se foliar spray to improve the drought tolerance potential of wheat. Additionally, we also examined the effect of supplemental Se on uptake of nutrients using detection by ICP-OES. Foliar Se application significantly lowered osmotic potential (13%) that markedly improved turgor by 63%, enhanced transpiration rate (60%), improved accumulation of total soluble sugars (33%) and free amino acids (118%) and activity of antioxidant system which ultimately increased the grain yield by 24%. Supplemental Se also significantly increased Se contents (5.77µgg−1DW) and improved Fe (91%) and Na (16%) uptake, whereas it reduced Zn accumulation by 54% and did not affect Ca contents. The results supported our hypothesis that supplemental Se influences nutrients uptake and wheat yield through maintenance of turgor and gas exchange characteristics and enhancement in antioxidant system activity.

Enhancing selenium concentration in lentil (Lens culinaris subsp. culinaris) through foliar application

SUMMARYSelenium (Se) is an essential micronutrient for human and animal health. Globally, more than one billion people are Se deficient due to low dietary Se. Low dietary intake of Se can be improved by Se supplementation, food fortification and biofortification of crops. Lentil (Lens culinaris Medikus subsp. culinaris) is a popular cool-season food legume in many parts of the world; it is naturally rich in Se and therefore has potential for Se biofortification. An Se foliar application experiment at two locations and a multi-location trial of 12 genotypes at seven locations were conducted from April to December 2011 in South Australia and Victoria, Australia. Foliar application of a total of 40 g/ha of Se as potassium selenate (K2SeO4) – 10 g/ha during full bloom and 30 g/ha during the flat pod stage – increased seed Se concentration from 201 to 2772 μg/kg, but had no effect on seed size or seed yield. Consumption of 20 g of biofortified lentil can supply all of the recommended daily allowance of Se. After Se foliar application, cultivars PBA Herald XT (3327 μg/kg), PBA bolt (3212) and PBA Ace (2957 μg/kg) had high seed Se concentrations. These cultivars may be used in lentil biofortification. In the genotypic evaluation trial, significant genotype and location variation was observed for seed Se concentration, but the interaction was not significant. In conclusion, foliar application of Se as K2SeO4 is an efficient agronomic approach to improve seed Se concentration for lentil consumers and there is also scope for genetic biofortification in lentil.

Selenium protects olive (Olea europaea L.) from drought stress

The aim of this study was to evaluate if Se could be effective in reducing the stress caused by drought on olive (Olea europaea L.). Young water-stressed trees (cv. Maurino) were treated with sodium selenate solutions (50 and 150mgSeL−1) by foliar spray. Gas exchange, relative water content (RWC) and fruit yield were compared with well irrigated trees and stressed untreated trees. Furthermore, the activity of antioxidant enzymes ascorbate peroxidase (APX; EC 1.11.1.11), catalase (CAT; EC 1.11.1.6) and glutathione peroxidase (GPOX; EC 1.11.1.9) and the variations in the content of malondialdehyde (MDA) were investigated. The results indicated that under water stress, foliar application of Se could increase photosynthesis (PN) and fruit yield, regulate the water status of trees and maintain a sufficiently high level of leaf water content that was not achieved by the inhibition of transpiration rate (E), which instead was higher than that in water-stressed untreated trees. Se increased the activities of APX, CAT and GPOX, and reduced the content of MDA, which otherwise accumulated during oxidative perturbations. This research is the first that shows that Se application can improve olive resistance to drought, and more in general in a tree species, by protecting the cells from oxidative injuries and regulating water status.

Soil and foliar application of selenium in rice biofortification

Selenium (Se) is essential for humans and animals because of its antioxidant properties, which form part of a series of chemical reactions. The aim of this study was to evaluate the effect of different Se application forms and sources on rice growth, grain yield, and rice Se concentration and accumulation, as well the content of N, P, Mg, S, B, Cu, Fe, Mn, and Zn in rice grains. The experiment was carried out in a greenhouse with 4-dm3 pots containing a sandy clay loam Red-Yellow Latosol. The experimental design was a completely randomized 2×2×2 factorial scheme (two Se doses×two forms of Se application, soil or foliar×two Se sources, selenate or selenite), with five replicates. Selenium in rice plants was analyzed by total reflection X-ray fluorescence spectrometry (TXRF). The results shows that soil selenate application was more effective for shoot dry matter production and grain Se accumulation than selenite. Foliar application of both selenate and selenite increased grain yield. This study provides useful information concerning agronomic biofortification of rice, showing that both soil and foliar Se application could be used for increasing Se content in edible parts, which could result in health benefits.

Increasing Se concentration in maize grain with soil- or foliar-applied selenite on the Loess Plateau in China

Selenium (Se) is an essential mineral nutrient for animal and human growth. Deficiency in this element is a worldwide nutrition problem. Thus, this study determined the potential of increasing Se content in maize grain by using various Se fertiliser application techniques to improve the nutritional status of local residents. Field experiments were conducted on the Loess Plateau for two growing seasons to investigate the effects of different Se fertiliser application methods and application rates on the Se content in maize grain as well as the Se recovery, yield and status of other nutrients in maize grain under rain-fed conditions. Results show that soil and foliar Se applications exhibited no significant effects on maize biomass and grain yield as well as N, P, K, Ca, Mg, Fe, Mn, Cu and Zn contents in maize grain. However, both foliar and soil Se applications significantly improved the Se content in maize grain. Selenium content in maize grain is found to be linearly correlated with Se application rates, increasing from 0.12μgkg−1 to 0.33μgkg−1 by soil application at 1g of Se ha−1 and from 8.23μgkg−1 to 8.67μgkg−1 by foliar application at the same rate. Foliar application of Se showed higher Se recoveries in the grain compared with soil Se application: the former exhibited a maximum grain Se recovery rate of 52‰ and 106‰ in maize during the first and second growing seasons, respectively, whereas the latter was only 1.69‰ and 0.95‰, respectively. On the Loess Plateau in China, both soil and foliar Se applications effectively improved the Se content in maize grain. Compared with soil Se application, foliar Se application can improve the grain Se content in maize at reduced costs.

Impact of double Zn and Se biofortification of wheat plants on the element concentrations in the grain

Optimisation of the concentrations of essential mineral elements in staple grain diet and reduction in non-essential and potentially toxic elements would considerably alleviate mineral malnutrition and improve the health of humans. Here, wheat (Triticum aestivum L.) plants were biofortified with Zn and/or Se to determine the changes across 36 elements in the grain. The element concentrations were determined by multielemental k<sub>0</sub>-instrumental neutron activation analysis (k<sub>0</sub>-INAA). In comparison to grain from non-biofortified plants, Zn fertilisation increased the grain Zn, Ca, and Mo concentrations, whereas the foliar application of Se only increased the grain Se concentrations. Double biofortification (combined Zn fertilisation and foliar Se) was more effective for the increased Se concentrations in the grain, in comparison to the Se-only biofortified plants, with the grain Zn, Ca and Mo concentrations remained at the same levels as those for the Zn-only biofortified plants. Except for Ba, Br and Rb, the concentrations of the elements analysed were below the detection limits. Double biofortification might be a feasible strategy to efficiently coordinate the mineral quality of wheat grain, although the considerable concentrations of other essential and non-essential elements should not be neglected.