Application Of Selenium Research Articles

Selenyum Uygulamalarının Silajlık Mısırın Verim Parametreleri Üzerine Etkileri

In this study, the effects of sodium selenite and sodium selenate applications on laying, plant appearance, number of worm cobs, random number of plants, plant height, cob/plant ratio, leaf/stem ratio of silage maize plant were investigated. Selenium was applied at eight different levels (0-5-10-15-25- 50-75-100 g Se ha-1). Selenite was applied to the soil in liquid form before planting seeds, and selenate was applied to the leaf when the corn plant was 50-70 cm tall. Selenium applications did not statistically affect lying, plant appearance, worm cob number, randomized plant number and plant height values. Selenite applications affected the cob/plant ratio and leaf/stem ratio values statistically, the interaction of the year X subject was significant. In 2013, there was a statistical difference between the subjects, the highest values were obtained with 52% from 5 g Se ha-1 application, with 45% and 47% from 10 g Se ha-1 and 25 g Se ha-1 applications, respectively. Selenate applications did not affect the cob/plant ratio values statistically, but the leaf/stem ratios were affected, the highest values were obtained with 43% from 100 g Se ha-1 applications. It is known that selenium applications do not affect the yield and other plant properties in plants, but increase the selenium concentration of the grain or plant. However, some studies show that selenium application affects positively the plant as our study. It is thought that the effect of selenium in plant development may vary depending on the type and variety of the plant, many factors increase the selenium activity, especially outside the soil and climatic conditions, the application time, rate and method, the form of selenium and the plant species are effective.

Effect of Three Nanoparticles (Se, Si and Cu) on the Bioactive Compounds of Bell Pepper Fruits under Saline Stress.

The bell pepper is a vegetable with high antioxidant content, and its consumption is important because it can reduce the risk of certain diseases in humans. Plants can be affected by different types of stress, whether biotic or abiotic. Among the abiotic factors, there is saline stress that affects the metabolism and physiology of plants, which causes damage, decreasing productivity and quality of fruits. The objective of this work was to evaluate the application of selenium, silicon and copper nanoparticles and saline stress on the bioactive compounds of bell pepper fruits. The bell pepper plants were exposed to saline stress (25 mM NaCl and 50 mM) in the nutrient solution throughout the crop cycle. The nanoparticles were applied drenching solution of these to substrate (Se NPs 10 and 50 mg L−1, Si NPs 200 and 1000 mg L−1, Cu NPs 100 and 500 mg L−1). The results show that saline stress reduces chlorophylls, lycopene, and β-carotene in leaves; but increased the activity of some enzymes (e.g., glutathione peroxidase and phenylalanine ammonia lyase, and glutathione). In fruits, saline stress decreased flavonoids and glutathione. The nanoparticles increased chlorophylls, lycopene and glutathione peroxidase activity in the leaves; and ascorbate peroxidase, glutathione peroxidase, catalase and phenylalanine ammonia lyase activity, and also phenols, flavonoids, glutathione, β-carotene, yellow carotenoids in fruits. The application of nanoparticles to bell pepper plants under saline stress is efficient to increase the content of bioactive compounds in fruits.

Influence of organic manures and biofortification of selenium on growth, yieldand selenium contentof cucumber (Cucumis sativus L.)

Field experiment was conducted to study the influence of organic manures and biofortification of selenium on growth, yield and selenium contentof cucumber (CucumissativusL.) during 2019 at Koneripalayam village in Perambalur district, Tamil Nadu. The popular variety Green Long suitable for this region was used for the present study. The experiment was carried out during two seasonsviz., Season I (February-May) and Season II (July-October)in randomised block design with fifteen treatments and three replications. The results of the experiment revealed that application of 25 tFYM ha -1 and 2 kg CBF ha -1 along with foliar application of Se (20 µg L-1) significantly recorded the highest vine length (209.1 cm and 214.6 cm), number of leaves (108.2 and 113.7), leaf length (15.7 cm and 15.9 cm) and leaf breadth (16.2 cm and 16.5 cm) in first and second season, respectively. The highest number of fruits per vine (13.3 and 16.5), fruit length (19.6 cm and 20.8 cm), fruit girth (17.1 cm and 18.2 cm), mean single fruit weight (78.1 g and 81.2 g), fruit yield vine-1 (723.5 g and 1009.2 g)and selenium content per fruit (8.1 µg kg-1 and 10.6 µg kg-1) in first and second season respectively was obtained with1 t EM ha -1 + 2 kg CBF ha -1 + Se (20 µg L-1) as foliar application. Among all the organic manures, farmyard manure was proved to be superior in respect of growth parameters and enriched manure in respect of yield parameters. The foliar application of selenium was found to be the best method of its supplementation in plants and relatively higher values of Se content in fruits were noted with higher dose of Se as folior application.

The application of selenium combined with gibberellin enhances the yield and quality of Chrysanthemum morifolium Ramat cv. Hangju

The flowers of Chrysanthemum morifolium Ramat cv. Hangju (Hangbaiju) are taken as a traditional medicine and health promoting tea due to their flavonoids. Selenium (Se) and gibberellic acid (GA) affect the flavonoid content of C. morifolium. However, few studies have evaluated the effects of Se combined with GA on Hangbaiju. Here, two-year field experiments were conducted with Se (sodium selenite [Na2SeO3]) and GA (50 and 100 mg L−1) applications alone or in combination, and the treatments were denoted as CK, Se50, Se100, GA50, GA100, Se50+GA50, and Se100+GA100. Se and GA application decreased the leaf soluble sugar contents, increased the soluble protein contents, and enhanced superoxide dismutase (SOD) and catalase (CAT) activities. The enhanced SOD and CAT activities were more pronounced with GA applications alone than other treatments. Se and GA applications increased the flower yield of Hangbaiju, and the highest values were recorded with Se50+GA50 in 2017 and 2018. When Se was applied alone or in combination with GA, the soluble sugar contents in Hangbaiju flowers showed the same trend as the flavonoid content; when GA was applied alone, the opposite trend was recorded. This fact suggested that Se and GA application modulate plant allocation of photosynthates to different metabolic pathways. Se application alone or in combination with GA increased the Se and flavonoid contents; the highest values of soluble sugar, protein and water extract contents were recorded with the Se50+GA50 application in 2017 and 2018, and the results provide an innovative approach to enhance the yield and quality of Hangbaiju flowers.

Selenium applications enhance 2‐acetyl‐1‐pyrroline biosynthesis and yield formation of fragrant rice

AbstractSelenium (Se) is a beneficial element for plants and a necessary element for humans. Previous studies showed Se could increase 2‐acetyl‐1‐pyrroline (2‐AP) content in fragrant rice (Oryza sativa L.), but the underlying molecular mechanism remains largely unexplored. There are several methods for Se application in rice production, and it is not clear which is better. This study investigated the effects of three different Se application methods on 2‐AP biosynthesis, yield formation, and grain Se concentration of fragrant rice through a four‐season field experiment with two fragrant rice cultivars. For soil application, Se was applied as Se mineral powder as basal application to soil (36 g Se ha−1); for foliar application (FA), sodium selenate solution (40 μmol L−1) was applied as a foliar spray at heading stage; and for seed priming, fragrant rice seeds were primed with sodium selenate at 80 mg kg−1 concentration. The treatment without Se was taken as control (CK). The results showed Se applications increased grain 2‐AP content and grain yield by 3.95–22.32% and 1.03–8.05%, respectively. Compared with CK, Se applications regulated transcript levels of genes PRODH, BADH2, DAO, OAT, and P5CS2, which are involved in 2‐AP biosynthesis. Selenium applications also increased the contents of precursors (Δ1‐pyrroline, proline and pyrroline‐5‐carboxylic acid) and enhanced the activities of enzymes (proline dehydrogenase, △1‐pyrroline‐5‐carboxylic acid synthetase, ornithine aminotransferase, diamine oxidase), which are related to 2‐AP. Furthermore, Se applications increased grain Se concentration by 14.12–63.25%. The highest grain yield, grain 2‐AP content, and grain Se concentration were all recorded in the FA treatment.

Application of selenium and silicon to alleviate short-term drought stress in French marigold (Tagetes patula L.) as a model plant species

AbstractSelenium (Se) and silicon (Si) are the beneficial elements that may significantly modify plants’ tolerance to various types of biotic and abiotic stress. They may be particularly important due to the current climate changes. The aim of model experiments was to assess how selenium and silicon could alleviate short-term drought stress in French marigold (Tagetes patula L. “Pascal”). Tagetes plant species are economically important annual plants and are also very popular decorative flowering species in city parks due to its beautiful colored flowers and resistance on drought stress. Silicon was applied in the form of silica sol and choline-stabilized orthosilicic acid (ch-OSA). Selenium was applied in the form of sodium selenate (Na2SeO4). They were tested at the following concentrations (mg dm−3 of NS): silica sol – level I (23.25), level II (31.0); ch-OSA – level I (0.21), level II (0.63); and Se – level I (0.4), level II (0.8). The experiment showed that silicon had stimulating effect on the biometric parameters of control plants cultivated under an optimal water regime. When the plants treated with selenium were exposed to stress, the values of their biometric parameters were generally higher than in the plants treated with silicon. Both silicon and selenium significantly modified the gas exchange parameters. During the growing season, the net photosynthesis activity (PN), stomatal conductance (gs), and transpiration rate (E) tended to decrease, but they increased significantly when selenium and silicon were applied. In general, the factors significantly modified the plants’ content of macro- and micronutrients as well as the proportions between them. Both selenium and silicon alleviated the short-term drought stress in French marigolds as a model plant, but when silicon was applied, the positive effect was modified by the source and its concentration.

Selenium biofortification enhances ROS scavenge system increasing yield of coffee plants

There are conclusive evidences of selenium (Se) deficiency in Brazilian soils and foods. Brazil is the largest producer and consumer of coffee worldwide, which favors agronomic biofortification of its coffee. This study aimed to evaluate effects of foliar application of three formulations and six rates of Se on antioxidant metabolism, agronomic biofortification and yield of coffee beans. Seven Se concentrations (0, 10, 20, 40, 80, 100 and 160 mg L−1) were applied from three formulations of Se (sodium selenate, nano-Se 1500, and nano-Se 5000). Selenium application up to 40 mg L−1 increased the concentration of photosynthetic pigments such as chlorophylls, pheophytins and carotenoids in coffee leaves. Foliar application of Se ranging from 20 to 80 mg L−1 decreased lipid peroxidation and concentration of hydrogen peroxide, but increased superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase activities in coffee leaves. These results indicated that foliar Se application stimulates antioxidative metabolism to mitigate reactive oxygen species. Foliar application of 20 mg Se L−1 of sodium selenate increased coffee yield by 38%, and 160 mg Se L−1 of nano-Se 5000 increased dramatically coffee yield by 42%. Selenium concentration in grains ranged from 0.116 to 4.47 mg kg−1 (sodium selenate), 4.84 mg kg−1 (nano-Se 1500) and 5.82 mg kg−1 (nano-Se 5000). The results suggest the beneficial effect of Se on the increment of photosynthetic pigments, antioxidative metabolism, increased coffee yield and nutritional quality of grains. The recommended foliar Se application in this study can mitigate abiotic stressors such as high temperatures resulting in higher yield of coffee plants.

1Selenium supply alters the subcellular distribution and chemical forms of cadmium and the expression of transporter genes involved in cadmium uptake and translocation in winter wheat (Triticum aestivum)

BackgroundCadmium (Cd) accumulation in crops affects the yield and quality of crops and harms human health. The application of selenium (Se) can reduce the absorption and transport of Cd in winter wheat.ResultsThe results showed that increasing Se supply significantly decreased Cd concentration and accumulation in the shoot and root of winter wheat and the root-to-shoot translocation of Cd. Se application increased the root length, surface area and root volume but decreased the average root diameter. Increasing Se supply significantly decreased Cd concentration in the cell wall, soluble fraction and cell organelles in root and shoot. An increase in Se supply inhibited Cd distribution in the organelles of shoot and root but enhanced Cd distribution in the soluble fraction of shoot and the cell wall of root. The Se supply also decreased the proportion of active Cd (ethanol-extractable (FE) Cd and deionized water-extractable (FW) Cd) in root. In addition, the expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 significantly increased with increasing Cd concentration in root, and the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root was downregulated by increasing Se supply, regardless of Se supply or Cd stress. The expression of TaHMA3-b in root was significantly downregulated by 10 μM Se at both the 5 μM and 25 μM Cd level but upregulated by 5 μM Se at the 25 μM Cd level. The expression of TaNramp5-a, TaNramp5-b, TaHMA3-a, TaHMA3-b and TaHMA2 in shoot was downregulated by increasing Se supply at 5 μM Cd level, and 5 μM Se upregulated the expression of those genes in shoot at 25 μM Cd level.ConclusionsThe results confirm that Se application limits Cd accumulation in wheat by regulating the subcellular distribution and chemical forms of Cd in winter wheat tissues, as well as the expression of TaNramp5-a, TaNramp5-b and TaHMA2 in root.

Selenium loss and changes in product quality during cooking of selenium enriched potato tubers

Selenium biofortification is increasingly applied to improve selenium contents in the edible parts of crops. Potato (Solanum tuberosum L.) is a major food crop with wide availability of consumption, which is suitable for selenium biofortification. However, the processing and product quality of selenium-enriched potatoes has rarely been reported. Herein, selenium-enriched potato tubers (0.24 mg kg−1 fresh weight) were used to investigate selenium retention, loss details, and quality changes in different processed products. Final selenium contents of the products varied with different processing methods (P <0.01). Compared to fresh tubers, steaming resulted in the lowest loss rate of selenium (28.64 %), mainly related to decoction. Moderate loss rates of selenium were recorded in boiled tubers (42.44 %), French fries (44.73 %), and crisps (50.86 %), mainly related to decoction, cutting and hot cleaning, respectively. The highest loss rate was attributed to starch extraction (98.69 %), mainly related to crude protein. Selenium application delayed enzymatic discoloration of fresh-cut tubers (P < 0.05) and increased the proportion of large- to medium-sized starch granules (>30 μm) (P < 0.05) compared to the control. To minimize selenium loss, steaming is superior to boiling and frying for the processing of selenium-enriched potatoes, and it is not feasible to produce selenium-enriched starch.

Methionine selenium antagonizes LPS‐induced necroptosis in the chicken liver via the miR‐155/TRAF3/MAPK axis

Organic selenium has antioxidation and disease treatment effects. To explore the mechanisms of how methionine selenium alleviates necroptosis in the liver and whether this process is related to microRNA(miRNA) and the mitogen-activated protein kinase (MAPK) pathway,an animal model of methionine selenium and the lipopolysaccharide (LPS) interaction was established. The morphology, inflammatory factor (tumor necrosis factor-α [TNF-α]), necroptosis-related genes (RIP1, RIP3, MLKL, and caspase 8), MAPK pathway-related genes (JNK, ERK, and p38, p-JNK, p-ERK, and p-p38), gga-miR-155, TRAF3 (predicted target of gga-miR-155), and oxidative stress-related indicators (SOD, MDA, CAT, GSH, and GSH-Px) were analyzed from the perspective of the miR-155/TRAF3/MAPK axis to elucidate the mechanism of methionine selenium on the LPS-induced necroptosis mechanism in the chicken liver. The current results suggested that methionine selenium antagonizes oxidative stress, inflammation, and the MAPK pathway, thereby antagonizing the occurrence of necroptosis through multiple mechanisms. At the same time, methionine selenium affects miR-155/TRAF3/MAPK signaling, reduces miR-155 expression, and upregulates TRAF3 expression to inhibit necroptosis. Thisinformation provided new ideas and a theoretical basis for the practical application of methionine selenium, and it also enriched the study of miRNAs in birds and provided a reference for comparative medicine.

Optimization of Bacillus cereus Fermentation Process for Selenium Enrichment as Organic Selenium Source.

Selenium is an essential trace element and micronutrient for human health. Application of organic selenium in plants and microorganisms as trace element supplement is attracting more and more attention. In this study, Bacillus cereus, an important probiotic, was used for selenium enrichment with sodium selenite as selenium source. The growth curve of B. cereus was investigated, and 150 μg/ml was selected as the concentration of selenium for B. cereus fermentation. With application of response surface methodology, the optimal fermentation conditions were obtained as follows: inoculation quantity of 7%, culture temperature of 33°C, and shaking speed of 170 rpm, leading to the maximal selenium conversion ratio of 94.3 ± 0.2%. Field emission scanning electron microscope and energy dispersive spectrometry evidenced that inorganic selenium had been successfully transformed. This study may contribute to get a strain with high Se conversion ratio, so as to extract organic selenium in the form of selenoprotein to be used for further application.

The mixed application of organic and inorganic selenium shows better effects on incubation and progeny parameters

This experiment aims to study the effects of dietary selenium (Se) sources on the production performance, reproductive performance, and maternal effect of breeder laying hens. A total of 2,112 Hyline brown breeder laying hens of 42 wk of age were selected and randomly divided into 3 groups, with 8 repeats in each group and 88 chickens per repeat. The sources of dietary Se were sodium selenite (SS, added at 0.3 mg/kg), L-selenomethionine (L-SM, added at 0.2 mg/kg), and combination of SS and L-SM (SS 0.15 mg/kg + L-SM 0.15 mg/kg). The pretest period was 7 d, and the breeding period was 49 d. Compared with 0.3 mg/kg SS, the addition of 0.2 mg/kg L-SM in the diet significantly increased the hatchability (P < 0.05) and the Se content (P < 0.05) in egg yolk and chicken embryo tissues and improved the activity of yolk glutathione peroxidase (GSH-px) effectively (P < 0.05). Treatment with 0.2 mg/kg L-SM also reduced the content of yolk malondialdehyde (P < 0.05) and significantly improved the antioxidant performance of 1-day-old chicks, as manifested by increased activity of antioxidant enzymes (GSH-px, total antioxidant capacity and the ability to inhibit hydroxyl radicals) in serum, pectoral, heart, and liver (P < 0.05). This treatment decreased the malondialdehyde content (P < 0.05) and increased the expression of liver glutathione peroxidase 4 and deiodinase 1 mRNA (P < 0.05). Adding L-SM to the diets of chickens increased the hatchability of breeder eggs as well as the amount of Se deposited and antioxidant enzyme activity in breeder eggs and embryos. Compared with SS, L-SM was more effectively transferred from the mother to the embryo and offspring, showing efficient maternal nutrition. For breeder diets, the combination of organic and inorganic Se (0.15 mg/kg SS + 0.15 mg/kg L-SM) is an effective nutrient supplementation technology program for effectively improving the breeding performance of breeders and the antioxidant performance and health level of offspring chicks.

Strategies for applying selenium for biofortification of rice in tropical soils and their effect on element accumulation and distribution in grains

This study aimed to investigate the effects of the selenium (Se) application via soil (SeVI) and leaf (SeIV and SeVI) on agronomic attributes of rice and the spatial distribution of Se and other elements in biofortified rice grains. For this, a field trial was conducted using six Se rates (0, 5, 10, 20, 40, and 80 g ha−1). Physiological evaluations in rice leaves, rice grain yield, and Se and other elements content were assessed. Spatial distributions of Se and other elements were visualized mapping the biofortified rice grains with μXRF. The results showed that the strategies and rates of Se applied to the plants were effective for producing Se-rich rice grains. Although Se application did not change the rice yield, it affected some enzyme activities, improving the antioxidant system of the plant. The spatial distribution of the different elements found in the biofortified rice grains varied substantially, with Se accumulations mainly in the endosperm, whereas P, K, Fe, and Zn accumulate in the embryo. Agronomic biofortification of rice with Se, via soil or leaf, is a promising strategy to be adopted in tropical soils in order to produce rice grains with adequate Se contents for human consumption.

Effects of foliar selenium application on growth and rhizospheric soil micro-ecological environment of Atractylodes macrocephala Koidz

Atractylodes macrocephala (A. macrocephala), a famous medicinal herb in China, is widely cultivated and consumed in China with various beneficial effects. Numerous studies have shown that selenium (Se) plays an important role in promoting plant growth, although Se has not been considered an essential element for higher plants. The objectives of this research were to determine the effects of foliar Se application (0, 2.5, 5.0, 10.0 and 20.0 mg m−2 Se in sodium selenite, sprayed monthly from May to August) on the growth and rhizospheric soil micro-ecological environment of A. macrocephala, and explore the possible mechanisms underlying plant response to foliar Se application through a field experiment. The results were: The foliar application of 5.0 mg m−2 Se significantly increased the survival rate of A. macrocephala compared to the control. The yield of A. macrocephala was increased when the Se level maintained belowed 10.0 mg m−2 but decreased when Se level reached 20.0 mg m−2. The Se content in the rhizome of A. macrocephala showed a significant positive correlation with the Se level, while the insect attack rate was significantly negatively correlated with the Se level. However, foliar Se application hardly affected the concentration of bioactive compound atractylenolide in the rhizome of A. macrocephala. Notably, the application of foliar Se changed the content of partial soil nutrients, microbial diversity and composition in the rhizosphere soil of A. macrocephala. Bacterial diversity was positively correlated with A. macrocephala growth whereas fungal diversity was negatively correlated, suggesting that microbial diversity in the rhizosphere soils is closely related to plant growth. Moreover, correlation analysis showed that available potassium, Burkholderia and Cupriavidus in rhizospheric soil might be critical factors for promoting the growth of A. macrocephala. Overall, the foliar application of Se at moderate concentration was beneficial for the growth of A. macrocephala, and 5.0-10.0 mg m−2 Se level was the optimum. Our findings revealed novel insights into the response of A. macrocephala to foliar Se application from plant growth, rhizospheric soil nutrient and microbial community composition .

Selenium and silica nanostructure-based recovery of strawberry plants subjected to drought stress

Drought is an important environmental stress that has negative effects on plant growth leading to a reduction in yield. In this study, the positive role of nanoparticles of SiO2, Se, and Se/SiO2 (SiO2-NPs, Se-NPs and Se/SiO2-NPs) has been investigated in modulating negative effects of drought on the growth and yield of strawberry plants. Spraying of solutions containing nanoparticles of SiO2, Se, and Se/SiO2 (50 and 100 mg L−1) improved the growth and yield parameters of strawberry plants grown under normal and drought stress conditions (30, 60, and 100%FC). Plants treated with Se/SiO2 (100 mg L−1) preserved more of their photosynthetic pigments compared with other treated plants and presented higher levels of key osmolytes such as carbohydrate and proline. This treatment also increased relative water content (RWC), membrane stability index (MSI) and water use efficiency (WUE). In addition, exogenous spraying of Se/SiO2 increased drought tolerance through increasing the activity of antioxidant enzymes including catalase (CAT), ascorbate peroxidase (APX), guaiacol peroxidase (GPX) and superoxide dismutase (SOD) as well as decreasing lipid peroxidation and hydrogen peroxide (H2O2) content. Increase in biochemical parameters of fruits such as anthocyanin, total phenolic compounds (TPC), vitamin C and antioxidant activity (DPPH) in strawberry plants treated with Se/SiO2 under drought stress revealed the positive effects of these nanoparticles in improving fruit quality and nutritional value. In general, our results supported the positive effect of the application of selenium and silicon nanoparticles, especially the absolute role of Se/SiO2 (100 mg L−1), on the management of harmful effects of soil drought stress not only in strawberry plants, but also in other agricultural crops.

Effect of foliar application of selenium on morphological and physiological indices of savory (Satureja hortensis) under cadmium stress.

Cadmium is a heavy metal that pollutes the environment and affects plants physiologically and morphologically. Selenium is considered as a beneficial element, with effective roles in increasing plant tolerance to environmental stresses. A greenhouse factorial pot experiment was conducted to study the impact of selenium on traits of Savory plants under Cd stress. Experimental factors included soil contamination with cadmium (0, 75, 100, and 150 μM) and foliar spraying of selenium (0, 10, 20, and 40 μM of Sodium Selenate). Biomass, photosynthetic pigments including chlorophyll a, chlorophyll b, total chlorophyll, proline, total soluble solids, cell membrane leakage, relative water content of leaves antioxidant enzymes, and Cd and Zn concentration in shoot and root were recorded. Results revealed that Cd stress decreased vegetative growth criteria, photosynthetic pigments include chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid almost, 55%, 57%, 57%, and 68%, respectively, while poline, cell membrane leakage, peroxidase (POD), and catalase (CAT) antioxidant enzymes were increased with increasing Cd concentrations. Foliar spray of selenium reduced the toxic effects of Cd stress on savory plants via enhancing of proline content and stimulation of CAT and POD enzymes and limitation of cell membrane leakage. Also, selenium foliar spray improved chlorophyll content under Cd stress condition and decreased cadmium accumulation 29% in root, respectively. In general, these results suggest that foliar application of selenium could mitigate Cd toxicity and improve growth and antioxidant capacity of savory under different level of cadmium heavy metal stress.

Biofortification of Forage Peas with Combined Application of Selenium and Zinc Under Mediterranean Conditions

Agronomic biofortification can be used to alleviate the deficient intake of selenium (Se) and zinc (Zn) by livestock. These two essential micronutrients for human and animals play an important role in many physiological functions and biological processes. The aim of the present study was to evaluate the suitability of forage peas, crop with an increasing importance as plant protein source, to be biofortified with a combined treatment of Zn (as ZnSO4-7H2O) and Se (as Na2SeO4). A 2-year field experiment was established in southern Spain under semiarid Mediterranean conditions, by following a split-split-plot design. The study year (2017/2018, 2018/2019) was considered the main-plot factor, soil Zn application (50 kg Zn ha−1, nil Zn) as a subplot factor, and foliar application (nil, 10 g Se ha−1, 8 kg Zn ha−1, 10 g Se ha−1 + 8 kg Zn ha−1) as a sub-subplot factor. The combined application of 50-kg soil Zn ha−1 and the foliar application of 10 g Se ha−1 + 8 kg Zn ha−1 was the most effective treatment to increase the concentration in forage of Zn and Se, 4-fold and 5-fold, respectively, as well as the Zn bioavailability, forage yield (close to 30%), and crude protein (~ 8%). Thus, forage peas could be considered a very suitable crop to be included in biofortification programs under Mediterranean conditions with Zn and Se as target minerals.

Foliar application of zinc and selenium alleviates cadmium and lead toxicity of water spinach – Bioavailability/cytotoxicity study with human cell lines

The present study investigated the effects of foliar application of zinc (Zn) and selenium (Se) on bioavailability of Zn and Se and toxicity of cadmium (Cd) and lead (Pb) to different water spinach ecotypes (LA and HA) grown in slightly (XZ) or moderately (LJY) contaminated fields via in vitro digestion combined with Caco-2/HL-7702 cell model. The obtained results revealed that foliar application of Zn and Se promoted yield, increased total, bioaccessible and bioavailable fractions of Zn and Se in plants, indicating that foliar application is a feasible way of biofortification. Although there was no significant effect on liver cell proliferation (MTT), membrane stability (LDH) and hepatocyte enzyme (ALT and AST) activities, the obvious ecotype and soil dependent fluctuations of lipid peroxidation (MDA) and antioxidant enzyme (SOD, POD and CAT) activities in serum highly suggest that the low accumulator and clean field should be used in agricultural production rather than the high accumulator and contaminated farmland. Moreover, foliar application of Zn and Se improved nutritional quality of all water spinach genotypes in both fields, including increased Fe, vitamin C, cellulose and chlorophyll, maintained concentrations of potassium (K), manganese (Mn), copper (Cu), protein, and nitrate. These results demonstrate that this agricultural management practice may prove to be an effective approach for minimizing health risk and alleviating “hidden hunger” in the developing countries.

Effects of biochar and foliar application of selenium on the uptake and subcellular distribution of chromium in Ipomoea aquatica in chromium-polluted soils

The potential toxicity of Cr to plants poses a severe threat to human health. Biochar and Se can reduce the absorption of Cr and its phytotoxicity in plants, but the associated mechanisms at subcellular levels have not been addressed in depth. A study was designed to investigate the effects of biochar, foliar application of Se, and their combination on the physicochemical and biological properties of the soil, Cr availability, Cr absorption, and Cr subcellular distribution in each part of the plant, and biomass and quality of two water spinach (Ipomoea aquatica) genotypes. The results showed that biochar, Se, and their combination increased the organic matter content and available NPK nutrients in the soil and improved the urease, phosphatase, catalase, and sucrase activities in the soil. Furthermore, they also increased the number of bacteria, actinomycetes, and fungi in the soil, were conducive to dry matter accumulation in I. aquatica, and increased the contents of soluble sugar and soluble protein in its leaves. The Cr contents in the roots and shoots of I. aquatica under different treatments were reduced compared with those in the control group. The content of Cr(VI) in the root-soil of I. aquatica with low Cr accumulation and the contents of Cr in various parts of I. aquatica were lower than those in I. aquatica with high Cr accumulation, and the absorbed Cr was mainly accumulated in the roots. Cr was mainly distributed in the cell walls and soluble fractions of the roots, stems, and leaves of I. aquatica and was less distributed in the organelles. Biochar and Se helped to increase the proportion of Cr in the cell walls of the roots and soluble fractions of the leaves of I. aquatica. The effects of improving the soil properties, passivating and inhibiting Cr absorption by I. aquatica, and reducing the Cr proportion in the organelles of biochar were superior to those of Se application. The foliar application of Se and biochar had no synergistic effect on inhibiting Cr absorption by I. aquatica. Based on these findings, the application of biochar in Cr-contaminated soil or foliar application of Se with low Cr-accumulating plants may be effective means of reducing the Cr absorption by plants and its toxicity to ensure the safe production of agricultural products in Cr-contaminated regions.

Soil and foliar applications of silicon and selenium effects on cadmium accumulation and plant growth by modulation of antioxidant system and Cd translocation: Comparison of soft vs. durum wheat varieties

Minimization of Cd accumulation in wheat is an effective strategy to prevent Cd hazard to human. This study compared and highlighted the roles of soil and foliar applications of Se and Si effects on Cd accumulation and toxicity in soft and durum wheat. Soil Se (0.5–1.0 mg kg–1) and Si (3–6 mg kg–1) applications provided an effective strategy to reduce wheat grain Cd concentrations of both wheat varieties by 59–61 % and 16–30 %, but foliar Se (0.125−0.25 mM) and Si (2.5–5 mM) application reduced grain Cd of soft wheat by 20–36 %. Both soil and foliar Se and Si applications significantly alleviated Cd toxicity by regulation of Cd transport genes, as reflected by increased the grain yield and antioxidant enzymes activities, and reduced MDA in wheat tissues. Selenium applications were more effective than Si on the reduction of Cd-induced toxicity and concentrations in soft wheat, but not in durum wheat due to more tolerant to Cd. Downregulation of influx transporter (TaNramp5) and upregulation of efflux transporter (TaTM20 and TaHMA3) in soft wheat may contribute to the Si/Se-dependent Cd mitigation and enhance the tolerance to toxic Cd. Overall, Se/Si applications, especially soil Se, can be efficiently used for reducing grain Cd uptake from Cd-contaminated soils.