Increase In Selenium Concentration Research Articles

Reduction in Placental Metal and Metalloid in Preeclampsia: A Case-Control Study.

Preeclampsia is a primary placental disorder, with impaired placental vascularization leading to uteroplacental hypoperfusion. We aimed to investigate differences in metal and metalloid content between the placentas of women with preeclampsia and healthy controls. This was a case-control study in 63 women with preeclampsia and 113 healthy women. Clinical data were obtained from medical records. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the placental metals and metalloids content. Compared with healthy control subjects, preeclampsia was associated with a significantly lower concentration of essential elements (magnesium, calcium, iron, copper, zinc, and selenium) in the placental tissue. After multivariable adjustment, an interquartile range (IQR) increase in selenium concentration was associated with a reduced risk of preeclampsia with an OR of 0.50 (95% CI: 0.33-0.77). The joint effects of multiple selected metals and metalloids were associated with a reduced risk of preeclampsia. The lower placental magnesium, chromium, iron, zinc, and selenium concentrations of preeclampsia cases indicate a potential link to its pathogenesis. It also provides an intriguing avenue for future research in revealing the underlying mechanisms and potential intervention strategies for preeclampsia.

Selenium enrichment and quality improvement of Origanum vulgare plants grown under in vitro condition with salicylic acid

One of the important sources of human selenium intake is vegetables, so increasing of selenium in edible parts of plants, biofortification, provides an effective approach to reduce selenium deficiency. Origanum vulgare L. is an important medicinal plant which is also used as a valuable spice. The present study was done to evaluate the ability of selenium accumulation of micropropagated O. vulgare under sodium selenate and/or salicylic acid treatment. Micropropagation of O. vulgare was done from shoot-tips as explants on modified Murashige & Skoog (MS) medium. After 1 month, rooted plantlets were transferred to modified Murashige & Skoog solidified medium containing sodium selenate (0, 25 and 50 µM) and/or salicylic acid (0 and 100 mgL−1). After 4 wk, growth, selenium accumulation, biochemical parameters and oxidative stress indicators were determined. The results showed that the plantlets were able to accumulate 16.1 µg g−1 DW and 28.27 µg g−1 DW selenium in shoots at 25 and 50 µM selenate sodium concentrations respectively. Both concentrations of selenium increased shoot dry weight, length of shoot and root, soluble sugars and total protein content, peroxidase and superoxide dismutase activity. On the contrary, malondialdehyde content decreased under selenium treatment. It was found that by increasing selenium concentration the content of total protein, H2O2 and antioxidant enzymes activity increased significantly. Application of salicylic acid in combination with selenium improved growth but did not affect on selenium accumulation. The obtained results can be considered as the first report of biofortification of O. vulgare under tissue culture technique.

Blood Selenium Concentrations Are Inversely Associated with the Risk of Undernutrition in Older Adults.

Selenium is an essential trace element with an antioxidant and anti-inflammatory capacity that has been associated in experimental studies with beneficial effects on appetite control, the regulation of the gut microbiota, and control of the anabolic-catabolic balance. The main aim of the present study was to evaluate the association between circulating selenium concentrations and the risk of developing undernutrition in older adults. This was a cohort study with 1398 well-nourished community-dwelling individuals aged ≥ 65 years residing in Spain in 2017, who were followed for a mean of 2.3 years. Whole blood selenium was measured at baseline using inductively coupled plasma-mass spectrometry. Undernutrition was assessed at baseline and at follow-up, and defined as having at least one of the three GLIM phenotypic criteria (involuntary weight loss, a low body mass index, and a reduced muscle mass) and at least one of the two etiologic criteria (reduced food consumption or nutrient assimilation and inflammation/disease burden). During the follow-up, 142 participants (11%) developed moderate undernutrition and 113 (8.8%) severe undernutrition. The standardized relative risks of moderate and severe undernutrition at the 75th percentile of Se levels versus the 25th were 0.90 and 0.70, respectively. In dose-response analyses, the risk of severe undernutrition decreased linearly with increasing selenium concentrations. This association was independent of protein intake or diet quality and was stronger among participants with a diagnosis of a musculoskeletal disorder. The results suggest that an adequate dietary selenium status is needed to prevent undernutrition in older adults. Also, this may open the door for clinical trials with selenium supplementation, at doses considered as safe, to prevent undernutrition.

Increasing selenium concentration in Finnish organic milk using participatory action approach

Selenium (Se) is an essential trace element for animals. In Finland, Se supplementary feeding and Se-enriched macronutrient fertilisers are used in conventional farming because the Se availability from soil is extremely low. The objective of this study was to improve Se concentration in organic milk by replacing sodium selenite (SS) in mineral-vitamin mixture with selenium yeast (SY) either completely or partly (50/50). The feeding experiment was conducted on 15 certified organic dairy farms in Eastern Finland during spring 2008. The cross-over design consisted of three treatments (SS treatment, SY treatment, and SS/SY treatment), three experimental periods (28 days each), and three farm groups (different order of treatments). Replacing SS with the same amount (0.2 mg Se kg-1 feed dry matter) of SY more than doubled Se concentration in organic milk and their mixture resulted in slightly lower Se concentrations. In conclusion, SY supplementary feeding is needed to improve Se concentration in organic milk and Se supply to cows, their calves, and consumers.

Genetically Predicted Body Selenium Concentration and estimated GFR: A Mendelian Randomization Study

Selenium is a trace mineral that is commonly included in micronutrient supplements. The effect of selenium on kidney function remains unclear. A genetically predicted micronutrient and its association with estimated glomerular filtration rate (eGFR) can be used to assess the causal estimates by Mendelian randomization (MR). In this MR study, we instrumented 11 genetic variants associated with blood or total selenium levels from a previous genome-wide association study (GWAS). The association between genetically predicted selenium concentration and eGFR was first assessed by summary-level MR in the chronic kidney disease(CKDGen) GWAS meta-analysis summary statistics, including 567,460 European samples. Inverse-variance weighted and pleiotropy-robust MR analyses were performed, in addition to multivariable MR adjusted for the effects of type 2 diabetes mellitus. Replication analysis was performed with individual-level UK Biobank data, including 337,318 White individuals of British ancestry. Summary-level MR analysis indicated that a genetically predicted 1 SD increase in selenium concentration was significantly associated with lower eGFR (-1.05 [-1.28,-0.82] %). The results were similarly reproduced by pleiotropy-robust MR analysis, including MR-Egger and weighted-median methods, and consistent even in the multivariable MR adjusted for diabetes. In the UK Biobank data, genetically predicted higher selenium concentration was also significantly associated with lower eGFR (-0.36 [-0.52,-0.20] %), and the results were similar when body mass index, waist circumference, hypertension, and diabetes mellitus covariates were adjusted (-0.33 [-0.50,-0.17] %). This MR study supports the hypothesis that higher genetically predicted body selenium is causally associated with lower eGFR.

The Effect of Maternal Dietary Selenium Supplementation on Blood Antioxidant and Metabolic Status of Ewes and Their Lambs.

This study investigated the effect of dietary selenium supplementation (organic and inorganic) of late-gestation ewes on blood selenium concentrations and metabolic and antioxidant status indicators in ewes and their lambs. In addition, the efficacy of selenium transfer from ewes to lambs during the suckling period was determined. The study was conducted on 30 Merinolandschaf ewes and their lambs and lasted four months. The feed mixture of the control group (group I) contained no added selenium, while the feed mixture of group II was enriched with 0.3 mg/kg of organic selenium sources and the third group with 0.3 mg/kg of inorganic selenium sources. In ewes and their lambs, selenium supplementation significantly (p < 0.01; p < 0.05) increased selenium concentration, glutathione peroxidase, and superoxide dismutase activity and decreased malondialdehyde concentration compared to the control group. Selenium supplementation had a positive effect on metabolism and hematological indicators in lambs. A positive correlation was found between antioxidant indicators in the whole blood of ewes and lambs. The good transfer of selenium from ewes to lambs was complemented by higher correlation coefficients when the feed mixture was supplemented with organic compared to inorganic selenium.

Effects of Selenium on Growth and Selenium Content Distribution of Virus-Free Sweet Potato Seedlings in Water Culture.

Understanding the selenium tolerance of different sweet potato [Dioscorea esculenta (Lour.) Burkill] is essential for simultaneously for breeding of new selenium-tolerant varieties and improving the selenium content in sweet potato. Therefore, a greenhouse experiment was conducted from February to April 2022 to evaluate the effect of sweet potato cultivars and selenium (Na2SeO3) concentrations (0–40 mg/L) on plant growth, physiological activities and plant selenium content distribution. The results showed that when the selenium concentration was more than 3 mg/L, the plant growth was significantly affected and the plant height and root length were significantly different compared to the control. While the selenium concentration was 20 and 40 mg/L had the greatest effect on plant growth when the number of internodes and leaves of the plant decreased, the root system stopped growing and the number of internodes of the plant, the number of leaves and the dry-to-fresh weight ratio of the plant a very significant level compared to reached control. The relative amount of chlorophyll in leaves under treatment with a selenium concentration of 1 mg/L was increased, and the relative amount of chlorophyll in 3 mg/L leaves gradually increased with the increase in the selenium concentration. The values of the maximum photochemical efficiency PSII (fv/fm) and the potential activity of PSII (fv/fo) compared to the control under treatment with 40 mg/L selenium concentration and photosynthesis of plants was inhibited. The selenium content in root, stem and leaf increased with the increase in selenium concentration, and the distribution of selenium content in the plant was leaf <stem <root, and the selenium content in root was significantly higher than that in stem and leaf. In summary, the appropriate concentration of selenium tolerance has been determined to be 3 mg/L. The aquatic culture identification method of selenium tolerance of sweet potatoes and growth indices of various selenium tolerant varieties (lines) established in this study will provide a technical basis for selenium tolerant cultivation and mechanism research.

Increased selenium concentration in the synthesis of CdSe magic-sized quantum dots affects how the brain responds to oxidative stress.

CdSe magic-sized quantum dots (MSQDs) have been widely used as fluorescent probes in biological systems due to their excellent optical properties with a broader fluorescence spectrum and stable luminescence in biological media. However, they can be cytotoxic and alter the redox balance depending on the amounts of Cd2+ adsorbed on their surface. Thus, the present study aimed to evaluate whether increases in selenium concentration in the synthesis of CdSe-MSQDs decrease the oxidative stress caused by Cd2+ -based quantum dots. CdSe-MSQDs synthesized with different concentrations of selenium were investigated against oxidative stress in the brain of chicken embryos by examining total antioxidant capacity, lipid peroxidation, thiol, and glutathione contents, as well as the activities of glutathione peroxidase, superoxide dismutase (SOD), catalase (CAT), and glutathione reductase. In addition, the vascularization of the chorioallantoic membrane (CAM) analysis was performed. Higher selenium concentrations alter the surface defect levels (decrease free Cd2+ ) and controlled the oxidative effects of CdSe-MSQDs by reducing the lipid peroxidation, restoring the glutathione defense system and the antioxidant enzymes SOD and CAT, and maintaining the vascular density of the CAM. The current findings reinforce the study of the effects of the presence of Cd2+ ions on the surface of quantum dots, changing toxicity, and aiming interesting strategies of nanomaterials in biological systems.

Study of the Electrical and Dielectric behaviour of selenium doped CCTO ceramics prepared by a facile sol-gel route

A facile sol-gel technique was successfully employed to prepare CaCu3-xSexTi4O12 (x = 0, 0.1, 0.2, 0.3 mM) nanoparticles and after subsequent calcination and sintering at 950 °C and 1050 °C respectively, ceramics of these nanoparticles were obtained. The powder XRD profile reveals that samples have the perovskite phase of CaCu3Ti4O12. SEM micrograph shows the dense microstructure of the ceramics and EDX analysis illustrates the elemental composition of the products. The dielectric behaviour of these ceramics was studied as a function of frequency (1 Hz-1 MHz) with different selenium concentrations at ambient temperature. The results indicate that doping of selenium over the copper (Cu) site enhances the dissipation factor and depresses the dielectric constant (εr) of CaCu3Ti4O12 ceramics. The AC conductivity of the substance was found to decrease with an increase in selenium concentration. The magnitude of high resistivity at high concentrations was mainly caused by the rapid increase in mobility of the charge carriers in the ceramics and follows the positive temperature coefficient of the resistance (PTCR) type behaviour. Electric modulus spectrum of undoped and selenium doped CaCu3Ti4O12 samples indicate that the existence of the non-Debye type of relaxation behaviour. The results suggest that the change in dielectric properties of selenium doped CaCu3Ti4O12 samples may be associated with the lack of oxygen vacancies in the ceramic specimens.

Selenium Alleviates Inflammation in Staphylococcus aureus-Induced Mastitis via MerTK-Dependent Activation of the PI3K/Akt/mTOR Pathway in Mice.

Mastitis caused by Staphylococcus aureus infection not only causes serious economic losses, but also affects human health. Se plays an important role in body immunity. However, the mechanisms by which Se regulates mastitis induced by S. aureus are still principally unknown. The purpose of this study is to investigate whether Se can inhibit mastitis induced by S. aureus through regulation of MerTK. Sixty BALB/c female mice were fed low, normal, or high Se concentrations for 7weeks and then randomly divided into six groups (Se-Low Control group (LSN), Se-Normal Control group (NSN), Se-High Control group (HSN), Se-Low S. aureus group (LSS), Se-Normal S. aureus group (NSS), Se-High S. aureus group (HSS)). The regulation of Se on MerTK was detected via histopathological staining, western blot analysis, enzyme-linked immunosorbent assay, and qRT-PCR. With increased selenium concentrations, the levels of IL-1β, IL-6, and TNF-α decreased, while the phosphorylation levels of MerTK, PI3K, AKT, and mTOR increased. Therefore, this study showed that Se could alleviate S. aureus mastitis by activating MerTK and PI3K/AKT/mTOR pathway.

Mutual influence of selenium nanoparticles and FGF2-STAB\xae on biocompatible properties of collagen/chitosan 3D scaffolds: in vitro and ex ovo evaluation

In a biological system, nanoparticles (NPs) may interact with biomolecules. Specifically, the adsorption of proteins on the nanoparticle surface may influence both the nanoparticles' and proteins' overall bio-reactivity. Nevertheless, our knowledge of the biocompatibility and risk of exposure to nanomaterials is limited. Here, in vitro and ex ovo biocompatibility of naturally based crosslinked freeze-dried 3D porous collagen/chitosan scaffolds, modified with thermostable fibroblast growth factor 2 (FGF2-STAB®), to enhance healing and selenium nanoparticles (SeNPs) to provide antibacterial activity, were evaluated. Biocompatibility and cytotoxicity were tested in vitro using normal human dermal fibroblasts (NHDF) with scaffolds and SeNPs and FGF2-STAB® solutions. Metabolic activity assays indicated an antagonistic effect of SeNPs and FGF2-STAB® at high concentrations of SeNPs. The half-maximal inhibitory concentration (IC50) of SeNPs for NHDF was 18.9 µg/ml and IC80 was 5.6 µg/ml. The angiogenic properties of the scaffolds were monitored ex ovo using a chick chorioallantoic membrane (CAM) assay and the cytotoxicity of SeNPs over IC80 value was confirmed. Furthermore, the positive effect of FGF2-STAB® at very low concentrations (0.01 µg/ml) on NHDF metabolic activity was observed. Based on detailed in vitro testing, the optimal concentrations of additives in the scaffolds were determined, specifically 1 µg/ml of FGF2-STAB® and 1 µg/ml of SeNPs. The scaffolds were further subjected to antimicrobial tests, where an increase in selenium concentration in the collagen/chitosan scaffolds increased the antibacterial activity. This work highlights the antimicrobial ability and biocompatibility of newly developed crosslinked collagen/chitosan scaffolds involving FGF2-STAB® and SeNPs. Moreover, we suggest that these sponges could be used as scaffolds for growing cells in systems with low mechanical loading in tissue engineering, especially in dermis replacement, where neovascularization is a crucial parameter for successful skin regeneration. Due to their antimicrobial properties, these scaffolds are also highly promising for tissue replacement requiring the prevention of infection.

Increase of selenium concentration in wheat grains through foliar application of sodium selenate

Selenium (Se) in small amounts is an essential element for human beings and provides several health benefits. However, its deficiency in the population is commonly reported in the scientific literature. Thus, the biofortification of wheat crops shows promise as it is one of the world’s most consumed foods. The present work aimed to obtain a recommendation for selenium fertilization through foliar application for wheat (Triticum spp.) crops, with the goal of promoting the biofortification of the grains. For this purpose, an experiment was performed in field conditions, in which Se was applied in the form of sodium selenate at 4 different doses (0, 5, 10 and 20 g ha−1). After the physiological maturation of the wheat plants, samples were analyzed in order to assess the Se concentration in the aerial parts of the plants and in the grains, and to evaluate the agronomic productivity and efficiency. The Se dose of 5 g ha−1 provided Se accumulation in wheat grains and represented the highest efficiency in absorption with no compromise to the productivity. This dose can supply up to 75 % of the recommended daily intake (RDI) of this nutrient. Thus, the biofortification of wheat crops was achieved and revealed to be more efficient when Se is applied at lower doses.

Calculations of selenium and cadmium concentration dependent elastic and thermal properties of zinc-blende specimens under CdxZn1-xSeyTe1-y quaternary system with density functional theory

First principle based investigations on mechanical and thermal properties have been executed for the zinc-blende specimens constituting the CdxZn1-xSeyTe1-y system. Elastic stiffness constants of specimens have been increased with increasing selenium concentration at any fixed cadmium concentration, while reverse tendencies have been observed with increasing cadmium concentration at any fixed selenium concentration. Hardness of specimens has been increased with increasing selenium concentration at any fixed cadmium concentration, while it has been decreased with increasing cadmium concentration at any fixed selenium concentration. The phonon dispersion spectra indicate dynamical stability in each binary, but instability in each ternary and quaternary alloy in their zinc-blende structures. Mechanical stability, elastic anisotropy, compressibility, ductility, plasticity, mixing of covalent and ionic bonding with prominent role of covalent over ionic, prominent role of bending over stretching in chemical bonds and central nature of interatomic forces have been observed in each compound. Calculated Debye temperature has established ZnSe as the hardest and CdTe as the softest among all the compounds. The anharmonic nature of interactions between the atoms in any compound has been confirmed with respective calculated Gruneisen parameter. The computed thermal conductivity and melting point temperature of each specimen have also been reported in the present article.

The effect of sodium selenate on biochemical and morphological parameters of blood and reproductive indicators of sheep of selected breeds used in the Czech Republic

Introduction: In the Czech Republic, there is a deficiency of selenium in sheep due to its low level of occurrence in soil, thus in fodder. Selenium deficiency in these animals can manifest in a number of diseases. Therefore, sheep should be supplemented with preparations containing selenium with vitamin E, because Se is closely related to vitamin E, which plays an important role in the immune system. Aim: The aim of the study was to assess the selenium status of selected sheep breeds in the Czech Republic and to determine the effect of selenium and vitamin E supplementation on selected hematological, biochemical and enzymatic blood indicators and on reproductive indicators. Material and methods: The research material consisted of sheep, used in the Czech Republic, of three breeds: Šumavka (16), Valaszka (16) and Zwartbles (16). At the 3rd month of gestation, the sheep were injected with sodium selenate with vitamin E. In the blood of sheep, hematological, biochemical and enzymatic parameters were analized, and reproductive indicators of sheep were determined. Results and discussion: The concentration of Se in sheep was quite low at the beginning of the experiment (from 0.145 (AVR group) to 0.219 µmol/l (BZR group) and the highest concentration (1.322 µmol/l I BZR group) on the test III. It was shown in experimental groups that with increasing selenium concentration, GSH-Px activity increased from the lowest level of 53.77 (ASR group) to the highes: 222.88 U/gHb (BZR group). In sheep from experimental groups (ASR, AVR, BZR groups) better fertility was obtained, amounting to 96.3%, 95.5%,89.4%, respectively. Conclusions: In all groups of sheep there was a selenium deficiency. Supplementation turned out to be an effective method of compensating for its deficiency. The proper selenium status ensured better reproductive indicators for sheep.

Band Edge Tailoring in Few-Layer Two-Dimensional Molybdenum Sulfide/Selenide Alloys

Chemical alloying is a powerful approach to tune the electronic structure of semiconductors, and has led to the synthesis of ternary and quaternary two-dimensional (2D) dichalcogenide semiconductor alloys (e.g. MoSSe2, WSSe2 etc.). To date, most studies have been focused on determining the chemical composition by evaluating the optical properties, primarily via photoluminescence and reflection spectroscopy of these materials in the 2D monolayer limit. However, a comprehensive study of alloying in multilayer films with direct measurement of electronic structure, combined with first principles theory, is required for a complete understanding of this promising class of semiconductors. We have combined first-principles density functional theory calculations with experimental characterization of MoS2(1-x)Se2x (where x ranges from 0 to 1) alloys using X-ray photoelectron spectroscopy to evaluate the valence and conduction band edge positions in each alloy. Moreover, our observations reveal that the valence band edge energies for molybdenum sulfide/selenide alloys increase as a function of increasing selenium concentration. These experimental results agree well with the results of density functional theory calculations showing a similar trend in calculated valence band edges. Our studies suggest that alloying is an effective technique for tuning the band edges of transition-metal dichalcogenides, with implications for applications such as solar cells and photoelectrochemical devices.

(X, T)-phase diagram of TlIn(S1–xSex)2 solid solutions (x = 0, 0.02, 0.06, 0.10, 0.15 and 0.25). Temperature dependences of thermal expansion and optical anisotropy parameters

ABSTRACT Basing on dilatometric and optical anisotropy studies, we have obtained (x, T)-phase diagram for TlIn(S1–xSex)2 solid solutions in the range 0 ≤ × ≤ 0.25 of selenium concentrations. It has been found that increasing selenium concentration leads to decrease in almost all of phase transition (PT) temperatures. At the same time, the temperature Ti of PT into incommensurate phase for the polytype c = c 0 increases at the selenium concentrations higher than 0.1, and we observe a tendency to broadening of the temperature region where the incommensurate phase exists. The incommensurate–ferroelectric PT reveals a notably diffuse character. We have also demonstrated that the TlIn(S1–xSex)2 solid solutions have a polytype structure. It manifests itself in availability of additional PT in the solid solutions with 0 ≤ × ≤ 0.05. Most probably, the latter corresponds to ferroelectric transformation in the polytype with c = 16c 0.

Selenium-associated DNA methylation modifications in placenta and neurobehavioral development of newborns: An epigenome-wide study of two U.S. birth cohorts

Background/AimSelenium (Se) levels in pregnancy have been linked to neurobehavioral development of the offspring. DNA methylation is a potential mechanism underlying the impacts of environmental exposures on fetal development; however, very few studies have been done elucidating the role of DNA methylation linking prenatal Se and child neurobehavior. We aimed to investigate the associations between placental Se concentration and epigenome-wide DNA methylation in two U.S. cohorts, and to assess the association between Se-related DNA methylation modifications and newborns’ neurobehavior. MethodsWe measured placental Se concentrations in 343 newborns enrolled in the New Hampshire Birth Cohort Study and in 141 newborns in the Rhode Island Child Health Study. Genome-wide placental DNA methylation was measured by HumanMethylation450 BeadChip, and newborn neurobehavioral development was assessed by the NICU Network Neurobehavioral Scales (NNNS). We meta-analyzed the associations between placental Se concentration and DNA methylation in each cohort, adjusting for covariates. We also fit multiple linear regression and ordinal logistic regression for methylation and newborn NNNS summary scores. ResultsWe identified five Se-related differentially methylated CpG sites. Among them was cg09674502 (GFI1), where selenium concentration was positively associated with methylation (β-coefficient = 1.11, FDR-adjusted p-value = 0.045), and where we observed that a one percent methylation level increase was associated with a 15% reduced odds of higher muscle tone in the arms, legs and trunk of newborns, (OR [95% Confidence Interval, CI] = 0.85 [0.77, 0.95]). We also observed for each interquartile range (IQR) increase in selenium concentration in the placenta, there was 1.76 times greater odds of higher hypotonicity (OR [95% CI] = 1.76 [1.12, 2.82]). ConclusionsPlacental selenium concentration was inversely associated with muscle tone of newborns, and hypermethylation of GFI1 could be a potential mechanism underlying this association.

Effects of different selenium concentrations on the stress resistance of grape seedlings

The effects of different concentrations of selenium (0.00, 0.05, 0.10, 0.25, 0.50, 1.00, 2.00 mg/L) on the stress resistance of grape seedlings were studied by pot experiment. The results showed that the proline content in different parts of grape seedlings showed an increasing trend with the increase of selenium concentration. The activities of SOD, POD and CAT, as well as the relative conductivity, malondialdehyde and soluble protein content of grape seedlings increased first and then decreased with the increase of exogenous selenium concentration. When the concentration of selenium was 0.50 mg/L, the antioxidant enzyme activity and the content of permeate in grape seedlings reached the maximum. In summary, low concentration of selenium can effectively improve the stress resistance of grape seedlings, but when the concentration of selenium is higher than 0.50 mg/L, it has a toxic effect on grape seedlings.

The selenium accumulation characteristics of grape seedlings

To study the selenium accumulation characteristics of fruit tree, different selenium concentrations (0.00, 0.05, 0.10, 0.25, 0.50, 1.00, 2.00 mg/L) were used on the grape seedlings, and the selenium accumulation characteristics of grape seedlings were studied by a pot experiment. With the increase of selenium concentration in culture medium, the biomass of grape seedlings had increase trend when the culture medium selenium was no more than 0.05 mg/L, and decreased when the culture medium selenium was exceeded than 0.05 mg/L. When the culture medium selenium was 0.05 mg/L, the biomass of grape seedlings got the maximum. For selenium content in plants, with the increase of selenium concentration in culture medium, the selenium contents in roots and shoots of grape seedlings increased. Therefore, lower selenium concentration in culture medium could promote the growth of grape seedlings, while higher selenium concentration inhibited, and grape seedlings had strong selenium uptake ability.

Study on the selenium accumulation of peach seedlings

An experiment was conducted to study the effect of peach seedlings (Prunus davidiana) grown in nutrient solution with different selenium concentration. The results showed that selenium concentration were 0.05 and 0.10 mg/L which caused a marked increase of roots and shoorts biomass, and the root/shoot ratio were relatively low (0.180 and 0.170) compared with control, and other selenium treatments decreased significantly the biomass. Consequently, 0.05 and 0.10 mg/L selenium treatments were conducive to peach seedlings growth, while the peach seedlings was inhibited significantly by the increasing concentration of selenium (≥ 0.10 mg/L). Selenium content of peach seedlings increased remarkably with the increase of selenium concentration that indicated the accumulation of selenium in peach seedlings had a linear relation with the dose of selenium. Above all, when selenium concentration in the range of 0-0.10 mg/ L, which not only promotes peach seedlings growth, but also increases peach seedlings selenium content.