Se Fertilization Research Articles

Growth and physiological responses of cabbage cultivars biofortified with inorganic selenium fertilizers

Selenium (Se) is essential for humans and animals. Problems associated with Se deficiency in the population diets is spread throughout the world and its related to low Se concentration in the foods. This study aimed to evaluate the effectiveness of different sources and Se concentration on agronomic biofortification of cabbage and its effects on nutritional and photosynthetic parameters. Two cabbage cultivars were treated with five Se concentrations (0, 5, 15, 30 and 60 μM) and two sources (selenate and selenite). The concentration of Se in the cabbage heads increased continuously up to 60 μM, but with no effect on the N, P and S concentrations. At low Se concentration (5 μM), there was an increase in the net photosynthesis, stomata conductance, intern carbon concentration and transpiration, besides increases in photosynthetic pigment levels, which led to an increase of over 100% in head dry mass and yield. The cultivars responded differently to the treatments, but both were highlighting the efficiency of Se fertilization in the heads. Both chemical forms of Se can be used at low concentrations (5 and 15 μM) for the agronomic biofortification of cabbage, however, selenite demonstrated to be most efficient.

Crosstalk between Selenium and Sulfur Is Associated with Changes in Primary Metabolism in Lettuce Plants Grown under Se and S Enrichment.

This study investigated the beneficial effects of selenium (Se) and sulfur (S) enrichment on the primary metabolism in butterhead lettuce. The plants were treated with three levels of Se via foliar application in the presence of two S levels in the nutrient solution under greenhouse conditions. The lettuce plants that were exposed to the lower selenate level (1.3 μM) in combination with the adequate and high S supplies (1 and 2 mM, respectively) accumulated 38.25 ± 0.38 µg Se g−1 DM and 47.98 ± 0.68 µg Se g−1 DM, respectively. However, a dramatic increase in the Se concentration (122.38 ± 5.07 µg Se g−1 DM, and 146.71 ± 5.43 µg Se g−1 DM, respectively) was observed in the lettuce heads that were exposed to the higher selenate foliar application (3.8 μM) in response to the varied sulfate concentrations (S1 and S2, respectively). Under higher Se and S supplies in the lettuce plants, the levels of organic acids, including malic acid and citric acid, decreased therein to 25.7 ± 0.5 and 3.9 ± 0.3 mg g−1 DM, respectively, whereas, in the plants that were subjected to adequate S and lower Se fertilization, the malic acid, and citric acid levels significantly increased to 47.3 ± 0.4 and 11.8 ± 0.4 mg g−1 DM, respectively. The two Se levels (1.3 and 3.8 μM) under the S1 conditions also showed higher concentrations of water-soluble sugars, including glucose and fructose (70.8.4 ± 1.1 and 115.0 ± 2.1 mg g−1 DM; and 109.4 ± 2.1 and 161.1 ± 1.0 mg g−1 DM, respectively), compared to the control. As with the glucose and fructose, the amino acids (Asn, Glu, and Gln) exhibited strikingly higher levels (48.7 ± 1.1 μmol g−1 DM) under higher S and Se conditions. The results presented in this report reveal that the “crosstalk” between Se and S exhibited a unique synergistic effect on the responses to the amino acids and the soluble sugar biosynthesis under Se and S enrichment. Additionally, the Se-and-S crosstalk could have an important implication on the final nutritional value and quality of lettuce plants.

The salicylic acid mediates selenium-induced tolerance to drought stress in tomato plants

The role of selenium (Se) in mitigating detrimental effects of drought stress on the plants has been reported, but the mechanism is still unclear. In this study, the function of Se fertilization on tomato (Solanum lycopersicum L.) under drought stress was characterized. Our results showed that the growth reduction caused by drought stress was alleviated by application of exogenous Se to a large extent. In addition, the treatment of Se significantly increased the net photosynthetic rate (Pn), transpirational rate (Tr), stomatal conductance (Gs) and water use efficiency (WUE) than in the absence of Se under drought stress treatment. Se addition also significantly inhibited the increase of malondialdehyde (MDA), soluble sugar and proline levels of tomato leaves and produced less reactive oxygen species (ROS) accumulation under drought stress. Furthermore, Se supplementation to the nutrient solution significantly increased the endogenous salicylic acid (SA) and methylated SA (MeSA) levels in tomato roots and promoted the conversion from SA to MeSA in tomato leaves under drought stress conditions via regulating the expression levels of several genes involved in SA biosynthesis and conversion such as PAL1, ICS, SAMT and SABP2. But the pretreatment with ABT (1-aminobenzotriazole, a SA inhibitor) abolished the beneficial effect of Se on drought stress tolerance of plants. These results suggested that Se application promoted photosynthetic efficiency and plant growth, alleviated drought-induced oxidative stress, and increased the endogenous SA levels, thereby imparting drought stress tolerance of tomato plants. This study may provide a theoretical basis for utilization of Se fertilizer to improve the yield and quality of agricultural products under stress.

Transcriptome analysis revealed accumulation-assimilation of selenium and physio-biochemical changes in alfalfa (Medicago sativa L.) leaves.

Selenium (Se) is an increasing concern for investigators predominantly because of its consumption in the human body mainly from crops. As the fourth largest plant crop globally, alfalfa is one of the most important forages. Alfalfa was fertilized with selenium(IV) (Se(IV)) under field conditions to study the accumulation and assimilation of Se(IV) and to assess the impact of Se fertilization. It was analyzed that the physio-biochemistry, Se species, combined with transcriptome after spraying Se(IV) at different times (0, 12, and 48 h). 9402 and 12 607 differentially expressed genes (DEGs) were identified at 12 h (versus 0h) and 48 h (versus 12 h). DEG functional enrichments proposed two time-specific biological processes: Se(IV) accumulation was the primary process at 0-12 h, and its assimilation mainly occurred during 12-48 h. This was further proved by the separation of various Se speciation at different times. It showed that Se-supplementation also affected the soluble protein, soluble sugar, pigment contents and antioxidant capacity. Selenium-biofortification could improve the stress resistance of alfalfa by enhancing antioxidant system to scavenge reactive oxygen species (e.g. hydrogen peroxide) and boosting carbohydrate metabolism. By integrating physio-biochemistry, Se-related metabolites, and transcriptome under Se(IV) treatment, this study provides data to guide further work on Se-fortification in alfalfa. © 2022 Society of Chemical Industry.

Effects of inorganic and organic selenium intervention on resistance of radish to arsenic stress

Arsenic (As) pollution, a potential threat for human health, in vegetables is one of the primary sources of As intake by the human body. In the Pot Experiment, the As content, physiological index and antioxidant enzyme activity of radish were determined. The results demonstrated that the order of As concentration in radish tissues was roots > stems > leaves. Organic selenium (Se) can inhibit the absorption of arsenic in radish more effectively than inorganic Se. The application of organic Se and low concentration of selenite (Se(IV)) significantly enhanced the stress resistance of radish for increasing superoxide dismutase and peroxidase activity, increasing soluble protein, chlorophyll and proline content, and reducing malondialdehyde content. In contrast, the high concentration of Se(IV) and selenate (Se(VI)) treatment group demonstrated stress and toxicological effects on radish. This study provides an idea for further research on the remediation mechanism of Se to As toxicity and provides a reference for the adoption of Se fertilizer in agriculture.

Selenium Biofortification of Lettuce Plants (Lactuca sativa L.) as Affected by Se Species, Se Rate, and a Biochar Co-Application in a Calcareous Soil

Selenium biofortification of lettuce plants was studied for two rates (5 and 10 mg kg−1 soil) of either selenate or selenite and for the effect of 5% w/w biochar addition. Lettuce seedlings were grown in pots containing 1 kg of a calcareous soil. Twelve weeks later, the plants were harvested and selenium (Se), phosphorus (P), and sulfur (S) concentrations were determined in heads and roots. Plant growth characteristics were measured and plant biometrics were assessed by NDVI, NDRE, and SPAD measurements. The highest Se concentration of 315.19 mg kg−1 D.W. and the highest amount of Se taken up by plants (950.5 μg/pot) were observed for the low selenate rate with biochar. The corresponding values for selenite treatments were an order of magnitude lower. Although in general, minor to severe toxicity symptoms occurred with selenium application in no biochar treatments (except selenite low rate), the addition of biochar secured plant growth and increased S and P concentrations in plants, regulating Se uptake by plants at high selenite rate and allowing maximum plant uptake at the low selenate rate. To propose an appropriate Se fertilization rate, the fate of excess selenates in the soil environment should be examined and experimentation under soil conditions is necessary.

Effects of two different selenium fertilizers on accumulation of selenium and heavy metals in rice grains in field trials

Selenium (Se) is a nutritionally important micronutrient for humans. The use of Se fertilizers is often the most feasible approach to precisely increase Se contents in rice grains, but the effects of common commercial Se fertilizers on producing Se-rich rice remain to be investigated. In this study, we compared the effects of liquid and granular Se fertilizers on the accumulation of Se and heavy metals in rice grains of four different varieties in field. Results showed that Se accumulation in rice grains was affected by the form of fertilizers, applied concentrations of Se fertilizers, and rice varieties. Liquid fertilizer displayed significantly higher Se transfer efficiency than granular fertilizer, whereas the granular fertilizer had a slightly higher effect on organic Se accumulation. More than 95.5% Se in grains were organic Se, with selenomethionine (SeMet) being the dominant one. The proportion of organic selenocysteine (SeCys2) in grains was significantly higher in treatments with liquid fertilizer. Both forms of fertilizers significantly reduced the accumulation of cadmium, lead, and arsenic. Collectively, our study provides a reference for producing Se-rich rice in a more competitive manner in practice.

Selenium in Wheat from Farming to Food.

Selenium (Se) plays an important role in human health. Approximately 80% of the world's population does not consume enough Se recommended by the World Health Organization. Wheat is an important staple food and Se source for most people in the world. This review summarizes literature about Se from 1936 to 2020 to investigate Se in wheat farming soil, wheat, and its derived foods. Se fortification and the recommended Se level in wheat were also discussed. Results showed that Se contents in wheat farming soil, grain, and its derived foods around the world were 3.8-552 μg kg-1 (mean of 220.99 μg kg-1), 0-8270 μg kg-1 (mean of 347.30 μg kg-1), and 15-2372 μg kg-1 (mean of 211.86 μg kg-1), respectively. Adopting suitable agronomic measures could effectively realize Se fortification in wheat. The contents in grain, flour, and its derived foods could be improved from 93.94 to 1181.92 μg kg-1, from 73.06 to 1007.75 μg kg-1, and from 86.90 to 587.61 μg kg-1 on average after leaf Se fertilizer application in the field. There was a significant positive correlation between the Se content in farming soil and grain, and it was extremely the same between the foliar Se fertilizer concentration rate and the grain Se increased rate. The recommended Se fortification level in cultivation of wheat in China, India, and Spain was 18.53-23.96, 2.65-3.37, and 3.93-9.88 g hm-2, respectively. Milling processing and food type could greatly affect the Se content of wheat-derived food and should be considered seriously to meet people's Se requirement by wheat.

Effects of Foliar Spraying with Different Concentrations of Selenium Fertilizer on the Development, Nutrient Absorption, and Quality of Citrus Fruits

Selenium (Se) fertilizer has a good effect on many field crops, but there are few reports on the application of Se fertilizer on citrus. We investigated the effects of 0 mg/L (CK, water treatment), 50 mg/L, 100 mg/L, 150 mg/L, and 200 mg/L sodium selenite aqueous solutions on the growth, nutrition, and fruit quality of 15-year-old citrus unshiu (Citrus reticulata Blanco cv. Succosa). The results showed that a low concentration of Se fertilizer promoted the growth and development of the citrus plan, and a high concentration of Se fertilizer was found to slightly inhibit the growth and development of the plant. Among the different treatment groups, 150 mg/L selenium fertilizer showed have the best effect on these evaluated parameters. The results thus suggest that 150 mg/L of Se fertilizer promotes the formation of chlorophyll in the leaves of the test plant and increases the longitudinal and transverse diameter of the fruits and weight of single fruit, significantly enhancing the activity of antioxidant enzymes in the leaves, promoting the absorption of nutrients in the leaves, increasing the contents of total sugar and vitamin, and decreasing the acidity in the fruits and the pericarp thickness. It also promoted the accumulation of the total selenium content in the leaves and fruits and consequently improved the quality of the fruits. These results showed that appropriate concentration of Se treatment can improve the activity of antioxidant enzymes to enhance plant stress resistance, regulate the content of sugar and acid in fruits, and improve the quality of fruits.

Using 77Se-Labelled Foliar Fertilisers to Determine How Se Transfers Within Wheat Over Time.

Foliar selenium (Se) fertilisation has been shown to be more efficient than soil-applied fertilisation, but the dynamics of absorption and translocation have not yet been explored. An experiment was undertaken to investigate time-dependent changes in the absorption, transformation, and distribution of Se in wheat when 77Se-enriched sodium selenate (Sefert) was applied to the leaves at a rate of 3.33 μg Se per kg soil (equivalent to 10 g ha−1) and two growth stages, namely stem elongation, Zadoks stage 31/32 (GS1), and heading stage, Zadoks stage 57 (GS2). The effect of urea inclusion in foliar Se fertilisers on the penetration rates of Se was also investigated. Wheat was harvested at 3, 10, and 17 days and 3, 10, and 34 days after Se applications at GS1 and GS2, respectively. Applying foliar Se, irrespective of the formulation, brought grain Se concentration to a level high enough to be considered adequate for biofortification. Inclusion of N in the foliar Se solution applied at an early growth stage increased recoveries in the plants, likely due to improved absorption of applied Se through the young leaves. At a later growth stage, the inclusion of N in foliar Se solutions was also beneficial as it improved the assimilation of applied inorganic Se into bioavailable selenomethionine, which was then rapidly translocated to the grain. The practical knowledge gained about the optimisation of Se fertiliser formulation, method, and timing of application will be of importance in refining biofortification programs across different climatic regimes.

Comparative study of the effects of selenium yeast and sodium selenite on selenium content and nutrient quality in broccoli florets (Brassica oleracea L. var. italica).

Approximately 0.5-1 billion people worldwide face the risk of selenium (Se) deficiency because of the low Se concentration in their diets. Broccoli can accumulate Se and comprises a source of daily Se supplement for humans. Se biofortification is an effective strategy for enhancing Se content in crops. In the present study, the effects of Se yeast and selenite application on the Se content and nutrient quality of broccoli were investigated. Broccoli growth was promoted by Se yeast but inhibited by selenite. The total Se content of broccoli florets remarkably increased with increasing exogenous Se fertilizer concentrations. The main Se species in broccoli florets were methyl-selenocysteine and selenomethionine, and their contents were significantly higher under Se yeast treatments than under selenite treatments. Se(VI) was detected only under selenite treatments. Se yeast and selenite had different influences on soluble sugar, soluble protein, vitamin C and free amino acid contents in broccoli florets. The total phenolic acid and glucosinolate contents were substantially increased by Se yeast and selenite, although the total flavonoid content was reduced by Se yeast. Tests on antioxidant enzyme activities revealed that several antioxidant enzymes (catalase, peroxidase, superoxide dismutase and glutathione peroxidase) responded to Se yeast and selenite treatments. Se yeast is preferred over selenite for maximizing Se uptake and nutrient accumulation in Se-rich broccoli cultivation. However, an extremely high Se content in broccoli florets cannot be directly consumed by humans, although they can be processed into Se supplements. © 2021 Society of Chemical Industry.

Selenium Nanoparticles as an Innovative Selenium Fertilizer Exert Less Disturbance to Soil Microorganisms.

Selenium (Se) is an essential trace element in the human body. Se-enriched agricultural products, obtained by applying Se fertilizer, are important sources of Se supplement. However, Se fertilizer may cause a series of environmental problems. This study investigated the transformation of exogenous selenium nanoparticles (SeNPs) and selenite (SeO32–) in soil and explored their effects on soil microbial community and typical microorganisms. SeNPs exhibited a slow-release effect in soil, which promoted the growth of soil microorganisms and enriched soil probiotics. SeO32– was converted to a stable and low toxic state in soil, increasing persistent free radicals and decreasing microbial abundance and diversity. The influences of SeNPs and SeO32– on two typical soil microorganisms (Bacillus sp. and Escherichia coli) were also evaluated, and SeNPs were more difficult to enter into microorganisms directly, with lower toxicity and higher safety. These results indicated that SeNPs were a more environment-friendly Se additive for agriculture applications. This work provides useful information for better understanding the environmental fate and behavior of Se fertilizer in the soil.

Selenium fertigation with nanobubbles influences soil selenium residual and plant performance by modulation of bacterial community

Although selenium (Se) is an essential microelement for humans and animals, it is a potentially toxic element due to its bioaccumulation potential. In this study, Se fertilizer was supplied in a greenhouse vegetable (cucumber) plantation using an innovative system consisting of nanobubbles (NB_Se) and compared to that under conventional conditions of fertigation (C_Se) with six doses. The results revealed thatNB_Se significantly reduced soil Se accumulation (38%−144%) and increased cucumber Se content compared with the C_Se treatments at the same Se dose. NB_Se significantly lowered the soil bacterial diversity, with an initial increase and then decrease with the Se doses. Bacterial associations and potential keystone taxa also differed between the NB_Se and C_Se. The greater abundance of oxidizing bacteria (indicated by the function composition of bacterial community) and the improved soil redox environment created by NBs sustained more available Se for plants, leading to a reduction in soil Se residual and an increase in the plant Se content. Our results highlight the feasibility and efficiency of NB_Se and demonstrate the important implications of Se for the maintenance of soil health and sustainability.

Effect of foliar application of the selenium-rich nutrient solution on the selenium accumulation in grains of Foxtail millet (Zhangzagu 10).

The foliar application of selenium (Se) is an effective method for biofortification of Se in crop grains in order to provide sufficient Se for human health. As a staple food in China, the foxtail millet (Setaria italica L.), which had been Se biofortification, would be helpful to overcome Se deficiency in the diet. The Se fertilizer and its application technology are vital for reducing environmental risk while enriching selenium. Hence, the Se-rich nutrient solution developed by ourselves was used, and the effect of its amount and growth stage applied on the accumulation of Se in grains of foxtail millet (Setaria italica L.) was studied in the present study. The results were as follows: (1) the Se concentration in grains increased with the Se application rate increasing, and the highest Se concentration in grains was 1.83 mg kg-1 at the sprayed concentration of 61.5 gSe hm-2; (2) the accumulation of Se sprayed in the grain-filling stage was 1.3-1.6 times higher than that in the joint stage; and (3) the organ damage could be found under low Se/S ratio, which happened in the rice leaves when the Se rate was higher than 76.875 gSe m-2 with the low sulfate application compared with the formulation. This Se-rich nutrient solution could be used to produce the Se-rich millet grains and foliar application in the reproductive stage to produce qualified Se-rich millet.

Selenium and salt interactions in sage (Salvia officinalis L.): Growth and yield, chemical content, ion uptake

Salinity (NaCl) is a major abiotic stress that limits crop production, especially under rainfed conditions. Selenium (Se), as an important micronutrient, plays a vital role in mitigating the detrimental effects of different abiotic stresses. The objective of this research was to examine the effect of Se fertilization on sage (Salvia officinalis L.) under different salt stresses. The results showed that Se treatments caused significant improvements in the dry weight (DW) of sage under salt stress. It was found that the DW was increased in the combined treatment of 10 ppm of Se and 100 mM/L of NaCl and was reduced at the highest level of NaCl (100 mM/L). The highest essential oil percentages were recorded in the first harvest (5 ppm of Se), and the control treatment in the second and third harvests but significantly affected the low and high NaCl levels in the sage. Additionally, the results in this study showed that the application of Se from 2.5 ppm to 10 ppm significantly increased the essential oil components when under salt stress. The results showed that 5 ppm of Se and 50 mM/L of NaCl increased SO42− and PO43− concentrations in the first and third harvests. In addition, significant increases in K+ uptakes and decreases in Na+ uptakes were detected when the Se was added while the sage was under salt stress, and the highest Ca2+ and Mg2+ concentrations were all found in the Se treatments as well as in the combined treatments of Se and NaCl.

Combined foliar and soil selenium fertilizer improves selenium transport and the diversity of rhizosphere bacterial community in oats.

Agronomic selenium (Se) biofortification of grain crops is considered the best method for increasing human Se intake, which may help people alleviate Se-deficiency. To investigate the efficiency of agronomic Se biofortification of oat, four Se fertilizer application treatments were tested: topsoil (T), foliar (S), the combination of T and S (TS), and control without Se application (CK). Compared with CK, TS significantly increased the 1000-grain weight, grain yield, Se contents in all parts of oats, contents of soil available N, K, and organic matter by 18%, 8.70%, 19.7-60.2%, 6.00%, 8.02%, and 17.95%, respectively. Leaves, roots, and ears had the highest conversion rate of exogenous Se in S (644.63%), T (416.00%), and TS (273.20%), respectively. TS also increased the activities of soil urease, alkaline phosphatase, and sucrose and the diversity of soil bacterial communities. TS and T increased the relative abundance of bacteria involved in the decomposition of organic matter, such as Actinobacteria, Gemmatimonadetes, Chloroflexi, and Bacteroidetes positively correlated with soil nutrients and enzyme activities, and reduced Proteobacteria and Firmicutes negatively correlated with them, Granulicella, Bacillus, Raoultella, Lactococcus, Klebsiella, and Pseudomonas. Furthermore, TS significantly increased the relative abundance of Planctomycetes, Chlorobi, Nitrospinae, Nitrospirae, Aciditeromonas, Gemmatimonas, Geobacter, and Thiobacter. T significantly increased the abundance of Lysobacter, Holophaga, Candidatus-Koribacter, Povalibacter, and Pyrinomonas. S did not significantly change the bacterial communities. Thus, a combined foliar and soil Se fertilizer proved conducive for achieving higher yield, grain Se content, and improving Se transport, the diversity of rhizosphere bacterial community, and bacterial functions in oats.

Combined foliar and soil selenium fertilizer increased the grain yield, quality, total se, and organic Se content in naked oats

BackgroundNaked oat (Avena nuda L.) is one of the most important, nutritionally rich grain crops produced worldwide. To determine the most reasonable selenium (Se) application method for naked oat, field experiments were conducted in the Loess Plateau from 2017 to 2018 to investigate the effects of Se fertilizer on grain yield, quality, Se content, and forms using a randomized block design with four treatments: foliar Se fertilizer application (S), soil Se fertilizer application (T), combined foliar and soil Se fertilizer application (TS), and control (CK) with no Se fertilizer. ResultsCompared to CK, the grain yield and Se content under the Se fertilizer treatments increased by 4.86–10.04% and 72.5–203.08%, respectively. Se forms of naked oat grains in T, S, and TS were mainly selenomethionine (SeMet). The SeMet content average increased by 45.69% (T), 53.75% (TS), and 51.19% (S), and the SeCys (selenocysteine) content increased by 90.73% (TS) and 75.43% (S), the Se fertilizer treatment increased the Se content in the roots, stems, leaves, and ears of oats. TS treatment, the Se content in ears was the highest. Se application significantly affected the crude protein and crude ash contents with the maximum recorded value observed in TS. Moreover, TS had significantly higher content of globulin, glutenin, and lysine, leucine, cystine, glutamic acid, and total amino acid contents for two consecutive years (P < 0.05). Se application significantly affected the iron (Fe), zinc (Zn), and calcium (Ca) contents (P < 0.05) with the Ca and Zn contents in the seeds reaching the maximum recorded values in TS. ConclusionsBased on these findings, combined foliar and soil Se fertilizer was determined to be the best Se application method on naked oats.

Valorization of selenium-enriched sludge and duckweed generated from wastewater as micronutrient biofertilizer

Selenium (Se) is an essential trace element for humans and animals with a narrow window between deficiency and toxicity levels. Application of conventional chemical Se fertilizers to increase the Se content of crops in Se deficient areas could result in environmental contamination due to the fast leaching of inorganic Se. Slow-release Se-enriched biofertilizers produced from wastewater treatment may therefore be beneficial. In this study, the potential of Se-enriched biomaterials (sludge and duckweed) as slow-release Se biofertilizers was evaluated through pot experiments with and without planted green beans (Phaseolus vulgaris). The Se concentration in the bean tissues was 1.1–3.1 times higher when soils were amended with Se-enriched sludge as compared to Se-enriched duckweed. The results proved that the Se released from Se-enriched biomaterials was efficiently transformed to health-beneficial selenoamino acids (e.g., Se-methionine, 76–89%) after being taken up by beans. The Se-enriched sludge, containing mainly elemental Se, is considered as the preferred slow-release Se biofertilizer and an effective Se source to produce Se-enriched crops for Se-deficient populations, as shown by the higher Se bioavailability and lower organic carbon content. This study could offer a theoretical reference to choose an environmental-friendly and sustainable alternative to conventional mineral Se fertilizers for biofortification, avoiding the problem of Se losses by leaching from chemical Se fertilizers while recovering resources from wastewater. This could contribute to the driver for a future circular economy.

Silicon and selenium fertilizer management improved productivity and aroma of fragrant rice

AbstractBoth Si and Se are the nutrient elements which had significant effects on crop growth and development. However, the application of Si and Se fertilizer management in field production of fragrant rice (Oryza sativa L.) was rarely reported. The present study was conducted with the objective to explore the effects of Si and Se fertilizer on fragrant rice performance though a six‐season field experiment. The Se rates were set at three levels: 0 g ha−1 (Se0), 36 g ha−1 (Se1), and 72 g ha−1 (Se2). The SiO2 rates were set at three levels: 0 kg ha−1 (Si0), 22.45 kg ha−1 (Si1), and 45 kg ha−1 (Si2). Compared with Si0Se0 treatment, Si and Se treatments significantly increased SPAD values and net photosynthetic rates of fragrant rice at tillering stage and heading stage. Higher grain yield, effectively panicle number and seed‐setting rate were also recorded in Si1Se1, Si1Se2, Si2Se1, and Si2Se2 treatments than Si0Se0 treatment in each cropping season. Moreover, Si and Se fertilizer management significantly increased the grain 2‐acetyl‐1‐pyrroline (2‐AP, main component of fragrant rice aroma) concentrations and the Si2Se1 treatment produced the highest or equally highest grain 2‐AP concentration in each cropping season.

Selenium Biofortification of Bamboo Shoots by Liquid Se Fertilization in the Culm Pith Cavity

Selenium is an essential micronutrient for human beings, but millions of people around the world suffer from Se deficiency. Soil fertilization and foliar fertilization are two major agronomic pract...