High NaCl Research Articles

Dietary Modification Alters the Intrarenal Immunologic Micromilieu and Susceptibility to Ischemic Acute Kidney Injury.

The versatility of the intrarenal immunologic micromilieu through dietary modification and the subsequent effects on susceptibility to ischemic acute kidney injury (AKI) are unclear. We investigated the effects of high-salt (HS) or high-fat (HF) diet on intrarenal immunologic micromilieu and development of ischemic AKI using murine ischemic AKI and human kidney-2 (HK-2) cell hypoxia models. Four different diet regimens [control, HF, HS, and high-fat diet with high-salt (HF+HS)] were provided individually to groups of 9-week-old male C57BL/6 mice for 1 or 6 weeks. After a bilateral ischemia-reperfusion injury (BIRI) operation, mice were sacrificed on day 2 and renal injury was assessed with intrarenal leukocyte infiltration. Human kidney-2 cells were treated with NaCl or lipids. The HF diet increased body weight and total cholesterol, whereas the HF+HS did not. Although the HF or HS diet did not change total leukocyte infiltration at 6 weeks, the HF diet and HF+HS diet increased intrarenal CD8 T cells. Plasma cells increased in the HF and HS diet groups. The expression of proinflammatory cytokines including TNF-α, IFN-γ, MCP-1, and RANTES was increased by the HF or HS diet, and intrarenal VEGF decreased in the HS and HF+HS diet groups at 6 weeks. Deterioration of renal function following BIRI tended to be aggravated by the HF or HS diet. High NaCl concentration suppressed proliferation and enhanced expression of TLR-2 in hypoxic HK-2 cells. The HF or HS diet can enhance susceptibility to ischemic AKI by inducing proinflammatory changes to the intrarenal immunologic micromilieu.

Effect of saline condition and application of rice husk silica extract on lettuce growth in hydroponics

The development of hydroponic vegetable production in coastal areas is faced with the constraints of irrigation water quality that has high NaCl. The purpose of this research is to study the interaction of NaCl concentration in the planting media and the concentration of silica extract of rice husk on the growth of lettuce plants. The study was conducted in April 2019-June 2019 at the greenhouse Palasari-Cibiru Bandung city with altitude + 800 m above sea level. This study used a factorial complete randomized design consisting of 2 factors with three replications. The first factor is the concentration of NaCl (n1 = 0 ppm, n2 = 1,460 ppm, n3 = 2920 ppm, n4 = 4380 ppm, and n5 5850 ppm) and the second factor is the concentration of silica extract of rice husk (s1 = 0 ml l−1, 30 ml l−1, and 45 ml l−1). Growth parameters observed were plant height, number of leaves, leaf area, root length, and plant fresh weight. The results showed that there was an independent effect on the concentration of NaCl on fresh plant weight. In the condition of saline media with a concentration of NaCl 1,460 ppm-2,920 ppm and the concentration of silica extract of rice husk, 30 ml l-1 lettuce plants can grow in good condition.

Selection and Validation of Reference Genes for RT-qPCR Analysis in Spinacia oleracea under Abiotic Stress

Reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) is an accurate and convenient method for mRNA quantification. Selection of optimal reference gene(s) is an important step in RT-qPCR experiments. However, the stability of housekeeping genes in spinach (Spinacia oleracea) under various abiotic stresses is unclear. Evaluating the stability of candidate genes and determining the optimal gene(s) for normalization of gene expression in spinach are necessary to investigate the gene expression patterns during development and stress response. In this study, ten housekeeping genes, 18S ribosomal RNA (18S rRNA), actin, ADP ribosylation factor (ARF), cytochrome c oxidase subunit 5C (COX), cyclophilin (CYP), elongation factor 1-alpha (EF1α), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), histone H3 (H3), 50S ribosomal protein L2 (RPL2), and tubulin alpha chain (TUBα) from spinach, were selected as candidates in roots, stems, leaves, flowers, and seedlings in response to high temperature, CdCl2, NaCl, NaHCO3, and Na2CO3 stresses. The expression of these genes was quantified by RT-qPCR and evaluated by NormFinder, BestKeeper, and geNorm. 18S rRNA, actin, ARF, COX, CYP, EF1α, GAPDH, H3, and RPL2 were detected as optimal reference genes for gene expression analysis of different organs and stress responses. The results were further confirmed by the expression pattern normalized with different reference genes of two heat-responsive genes. Here, we optimized the detection method of the gene expression pattern in spinach. Our results provide the optimal candidate reference genes which were crucial for RT-qPCR analysis.

Genome-Wide Identification of the NHX Gene Family in Punica granatum L. and Their Expressional Patterns under Salt Stress

Most cultivated lands are suffering from soil salinization, which is a global problem affecting agricultural development and economy. High NaCl concentrations in the soil result in the accumulation of toxic Cl− and Na+ in plants. Na+/H+ antiporter (NHX) can regulate Na+ compartmentalization or efflux to reduce Na+ toxicity. This study aims to identify the NHX genes in pomegranate (Punica granatum L.) from the genome sequences and investigate their expression patterns under different concentrations of NaCl stress. In this study, we used the sequences of PgNHXs to analyze the physicochemical properties, phylogenetic evolution, conserved motifs, gene structures, cis-acting elements, protein tertiary structure and expression pattern. A total of 10 PgNHX genes were identified, and divided into three clades. Conserved motifs and gene structures showed that most of them had an amiloride-binding site (FFI/LY/FLLPPI), except for the members of clade III. There were multiple cis-acting elements involved in abiotic stress in PgNHX genes. Additionally, protein-protein interaction network analysis suggested that PgNHXs might play crucial roles in keeping a balance of Na+ in cells. The qRT-PCR analysis suggested that PgNHXs had tissue-specific expressional patterns under salt stress. Overall, our findings indicated that the PgNHXs could play significant roles in response to salt stress. The theoretical foundation was established in the present study for the further functional characterization of the NHX gene family in pomegranate.

Investigation on initial atmospheric corrosion of copper and inhibition performance of 2-phenyl imidazoline based on electrical resistance sensors

The initial atmospheric corrosion of copper was investigated by electrical resistance sensor under different environmental factors (relative humidity, temperature, and NaCl loading density). The corrosion rate of Cu increases evidently with NaCl loading density, temperature and RH, but decreases with prolonged test. 2-phenyl imidazoline (2-PI) presents increasing inhibition efficiency on Cu with elevated temperatures at low NaCl loading density (≤40 μg/cm2), mainly due to that elevated temperature enhances the vapour pressure of 2-PI, however, 2-PI shows inferior performance on pre-corroded Cu at high NaCl loading density, possibly due to that the defective corrosion product layer formed at high RH retards the adsorption of 2-PI. Finally, molecular dynamic simulations were conducted to evidence the competitive adsorption advantage of 2-PI against H2O on Cu2O surface through chelation of 1-N of imidazoline with Cu(I).

Effect of sodium chloride on the expression of genes involved in the salt tolerance of Bacillus sp. strain “SX4” isolated from salinized greenhouse soil

Abstract Salt stress is one of the important adverse conditions affecting bacterium growth. How bacteria isolated from greenhouse soil cope with salt stress and regulate the genes responsible for salt tolerance are still unclear. We conducted RNA transcriptome profiling of genes contributing to the salt tolerance of a Bacillus sp. strain (“SX4”) obtained from salinized soil. Results showed that NaCl effectively regulated the growth of “SX4” in terms of cell length and colony-forming unit number decrease. A total of 121 upregulated and 346 downregulated genes were detected under salt stress with reference to the control. The largest numbers of differential expression genes were 17 in carbon metabolism, 13 in the biosynthesis of amino acids, 10 in a two-component system, and 10 in ABC transporter pathways for adapting to salt stress. Our data revealed that cation, electron and transmembrane transport, and catalytic activity play important roles in the resistance of bacterial cells to salt ions. Single-nucleotide polymorphism and the mutation of base pair T:A to C:G play potential roles in the adaptation of “SX4” to high NaCl concentrations. The findings from this study provide new insights into the molecular mechanisms of strain “SX4” and will be helpful in promoting the application of salt-tolerant bacteria.

Determination and mitigation of chemical risks in sufu by NaCl and ethanol addition during fermentation

This work investigated the changes in the risk factors associated with sufu fermentation, and the effects of NaCl and ethanol content on biogenic amine precursors and biogenic amines. The results demonstrated that all physicochemical indexes of sufu in the fermentation process met the standard limits. High NaCl concentration had a significant effect on the decrease of total volatile basic nitrogen (TVB-N) and biogenic amine in sufu at the curing stage. Furthermore, cadaverine and histamine contents were significantly reduced with increasing NaCl content. During the post-fermentation stage, H2S, TVB-N and total biogenic amine contents significantly decreased with high concentrations of ethanol. In addition, 16 % ethanol content had a significant effect on the putrescine, cadaverine and histamine contents. These results demonstrated that suitable concentrations of salt and ethanol could be used to produce high-quality sufu products with low biogenic amine content.

Electrochemical migration behavior of low-temperature-sintered Ag nanoparticle paste using water-drop method

The electrochemical migration (ECM) behavior of low-temperature-sintered Ag nanoparticle paste electrode was investigated using water-drop method. The effects of applied direct current bias voltage and NaCl concentration on ECM behavior were discussed. Results show that: at low NaCl concentration levels, mean time to failure caused by ECM decreased with increasing NaCl concentration due to the increase of solution conductivity; at medium NaCl concentration levels, dendrite growth was retarded due to the formation of AgOH or other insoluble products, while at high NaCl concentration levels, due to the turbulent hydrogen evolution, the second spreading of water drop resulted in the circuit broken and thus inhibited ECM behavior. Moreover, mean time to failure decreased with the rising applied bias voltage. More importantly, hexadecyltrimethylammonium chloride (CTAC) was proved to act as an effective inhibitor to migrate dendrite growth by selected adsorption. And the ECM inhibition efficiency increased with the concentration of CTAC. Relevant mechanisms of ECM behavior and ECM inhibition effect of CTAC for low-temperature-sintered Ag nanoparticle paste were proposed.

Biopolymer production by halotolerant bacteria isolated from Caatinga biome.

Saline environments are extreme habitats with a high diversity of microorganisms source of a myriad of biomolecules. These microorganisms are assigned as extremophiles recognized to be producers of new natural compounds, which can be synthesized by helping to survive under harshness and extreme conditions. In Brazil, in the saline and semi-arid region of Areia Branca (Caatinga biome), halotolerant bacteria (able to growth at high NaCl concentrations) were isolated from rhizosphere of native plants Blutaparon portulacoides and Spergularia sp. and their biopolymer production was studied. A total of 25 bacterial isolates were identified at genus level based on 16S rRNA gene sequence analysis. Isolates were mainly Gram-positive bacteria from Bacillaceae, Staphylococcaceae, Microbacteriaceae, and Bacillales XII incertae sedis families, affiliates to Bacillus, Staphylococcus, Curtobacterium, and Exiguobacterium genera, respectively. One of the Gram-negative isolates was identified as member of the Pseudomonadaceae family, genus Pseudomonas. All the identified strains were halotolerant bacteria with optimum growth at 0.6-2.0M salt concentrations. Assays for biopolymer production showed that the halotolerant strains are a rich source of compounds as polyhydroxyalkanoates (PHA), biodegradable biopolymer, such as poly(3-hydroxybutyrate) (PHB) produced from low-cost substrates, and exopolysaccharides (EPS), such as hyaluronic acid (HA), metabolite of great interest to the cosmetic and pharmaceutical industry. Also, eight bacterial EPS extracts showed immunostimulatory activity, promising results that can be used in biomedical applications. Overall, our findings demonstrate that these biomolecules can be produced in culture medium with 0.6-2.0M NaCl concentrations, relevant feature to avoid costly production processes. This is the first report of biopolymer-producing bacteria from a saline region of Caatinga biome that showed important biological activities.

Effect of Process Variables on the Crevice Corrosion in Type-304 Stainless Steels

Background: Corrosion is a major problem in most industries making use of metals across the world. The protection of metals and pipelines in the petroleum industry against different forms of corrosion has been of interest to stakeholders for many years. Objective: In this study, the effects of NaCl concentration, crevice scaling factor and immersion time on the percentage area attacked and the maximum depth of crevice attack in type- 304 stainless steels were investigated. Method: The assembly and experimentation of crevice attack in type-304 stainless steels were according to ASTM G-78. Furthermore, the open circuit potential of the system was determined and numerical optimisation of the process factors was conducted. Results: The open-circuit potential for creviced SS-304 revealed a greater susceptibility to crevice corrosion at higher NaCl concentrations. It was observed that the percentage area attacked and the maximum depth of attack increased with increasing NaCl concentration and time. However, the higher scaling factors led to a lesser area and depth of attack. Numerical optimisation revealed that the optimum value (minimum) of % area attacked and the maximum depth of attack were 0.00005847% and 0.00984 mm at 2.43 wt% NaCl, 19.3 crevices scaling factor and 15 days, respectively. Conclusion: It can be concluded that by taking appropriate measures of maintenance and avoidance of moist environment (supplying O and H2O), the crevice corrosion of SS-304 can be mitigated.

Fabrication of whey protein isolate-sodium alginate nanocomplex for curcumin solubilization and stabilization in a model fat-free beverage

The present study aimed to fabricate whey protein isolate (WPI)-sodium alginate (ALG) nanocomplexes for curcumin (CUR) stabilization in a model fat-free beverage. Mass ratio of 5:1 at pH 5.0 in the absence of NaCl was optimized for WPI-ALG nanocomplex fabrication. Mean particle size and zeta-potential of CUR-WPI-ALG nanocomplex was 209.9 nm and −39.1 mV at pH 5.0, respectively. Highest loading amount (LA) of CUR in CUR-WPI-ALG nanocomplex were 15.26 μg/mg. No obvious precipitates were observed for CUR-WPI-ALG nanocomplex under simulated food processing and storage conditions including high sucrose, high NaCl, and thermal treatment at 90 °C for 2 h. Fluorescence results confirmed that the spontaneous interaction between CUR and WPI-ALG nanocomplex was primarily motivated by hydrophobic interaction and hydrogen bonding. Compared with CUR (free), chemical stability (UV light, and heat), and DPPH scavenging capacities of CUR in CUR-WPI-ALG nanocomplex were strikingly improved.

Evaluation of physio-biochemical potentials of alkaliphilic bacterial diversity in bauxite processing residues of diverse restoration history

Bauxite residue, the waste by-product of bauxite ore processing in alumina industry is mostly deposited around the areas of alumina plants and often leads to a number of environmental and human health problems. Here we report the physico-chemical and microbiological analysis of bauxite residue samples of different restoration history (0–40 years). The samples were characterized by high alkalinity (pH 8.5–12.5) and metal content along with poor organic matter. While the presence of Sodalite, Hematite, Boehmite, Gibbsite, Anatase and Quartz was confirmed by X-ray powder diffraction (XRD) analysis, heavy metal contamination was evaluated by applying contamination factor and pollution load index. The aerobic microbial density as well as activity of the samples were in general very low and ranged from 1.2 to 8.96 × 102 cfu/g and 0.32–0.96 µg fluorescein/g/h. A total of 12 phenotypically distinguishable bacteria were isolated in pure form which showed significant tolerance to nickel (Ni), chromium (Cr), aluminium (Al), iron (Fe), manganese (Mn), magnesium (Mg) and lead (Pb), high pH and NaCl and were resistant to a number of antibiotics. Further, tolerance to alkalinity, transformation of waste to neutral one, production of diverse enzymes, extracellular polysaccharide and formation of biofilm, the unique features of these bacterial isolates could be of immense importance for potential applications in bioremediation and bioleaching.

Effect of phospholipids on the physicochemical properties of myofibrillar proteins solution mediated by NaCl concentration

In this study, the effect of phospholipids on the physicochemical properties of myofibrillar proteins (MP) solution was investigated at different NaCl concentration (0.3–0.7 mol/L). The results indicated the phospholipids addition increased the average particle size (i.e., from 1277–651 to 1546–1087 nm at 0.3–0.7 mol/L NaCl) and turbidity (i.e., from 0.323–0.139 to 0.729–0.551 at 0.3–0.7 mol/L NaCl) due to the enhanced hydrophobic interaction, and decreased the modulus of MP solution due to the reduction of disulfide bonds between MP. At 0.3–0.5 mol/L NaCl concentration, the formation of MP-phospholipids (MP-P) complexes resulted in the decreased protein solubility (i.e., 50.93%–75.67% and 41.28%–74.60% for MP and MP-P, respectively) and the increased viscosity of MP solution. However, at NaCl concentration close to 0.7 mol/L, the rheological properties of MP-P complexes did not change significantly like that of MP groups. This indicated the phospholipids addition could inhibit the salting-out effect of MP due to enhanced hydrogen bond between MP and water. Moreover, the phospholipids addition enhanced the emulsifying activity and emulsifying stability of MP solution at a high NaCl concentration (0.7 mol/L).

Potassium Lactate as a Strategy for Sodium Content Reduction without Compromising Salt-Associated Antimicrobial Activity in Salami.

Reformulating recipes of ready-to-eat meat products such as salami to reduce salt content can mitigate the negative health impacts of a high salt diet. We evaluated the potential of potassium lactate (KL) as a sodium chloride (NaCl) replacer during salami production. NaCl and KL stress tolerance comparisons showed that four food-derived Listeria innocua isolates were suitable as biologically safe Listeria monocytogenes surrogates. Effects of the high salt (4% NaCl) concentration applied in standard salami recipes and a low salt (2.8% NaCl) plus KL (1.6%) combination on product characteristics and growth of contaminating Listeria and starter culture were compared. Simulated salami-ripening conditions applied in meat simulation broth and beef showed that the low salt plus KL combination retained similar to superior anti-Listeria activity compared to the high salt concentration treatment. Salami challenge tests showed that the low NaCl plus KL combination had comparable anti-Listeria activity as the high NaCl concentration during ripening and storage. No significant differences were detected in starter culture growth profiles and product characteristics between the high NaCl and low NaCl plus KL combination treated salami. In conclusion, KL replacement enabled a 30% NaCl reduction without compromising the product quality and antimicrobial benefits of high NaCl concentration inclusion.

Enhanced conversion of α-cellulose to 5-HMF in aqueous biphasic system catalyzed by FeCl3-CuCl2

This study was to investigate the optimal additions of the cellulose decomposition reaction to obtain the most yield of 5-HMF and other furan derivatives in various biphasic systems with FeCl3-CuCl2 mixed catalysts, and explore its depolymerization kinetics. A series of controllable reactions have been performed under mild environmentally friendly atmosphere. The experiment results showed that 49.13 wt% of 5-HMF was the maximum production along with 2.98 wt% other furan derivatives catalyzed by mixed Lewis acid FeCl3-CuCl2 under the two phases which included high concentration NaCl aqueous phase and n-butanol organic phase at 190 °C for 45 min. The conclusion suggested that two-phase systems benefited the yield of 5-HMF, furan derivatives via extracting the target products from reaction phase to organic phase to avoid rehydration of 5-HMF. The kinetic calculation revealed the conversion with mixed catalysts had lower reaction apparent activation energy (21.65 kJ/mol, 190-230 °C) and the reaction rate was faster than that with acid-based catalysts. Based on experiment exploration, the probable mechanism of cellulose decomposition with FeCl3-CuCl2 was proposed.

Поиск природных штаммов дрожжей - продуцентов глицерина

Screening of glycerol-producing yeasts resistant to high osmotic pressure of substrates has been carried out among collection strains and strains isolated from natural sources associated with bee habitat. In total, more than 170 strains of osmotolerant yeasts were investigated which belong to 9 genera and the following13 species: Candida apicola, C. magnolia, Debaryomyces hansenii, D. marama, D. polymorphus, Hansenula ciferri, Kluyveromyces lactis, K. marxianus, Pichia farinose, Saccharomyces cerevisiae, Starmerella bombi, Schizosaccharomyces pombe, and Zhygosaccharomyces rouxii. The Kluyveromyces lactis VKPM Y-4429 strain producing 77.4 g/L of glycerol for 24 h of cultivation on media with a high glucose (300 g/L) and NaCl (5-6%) content was selected. These conditions cause osmotic shock, and as a consequence, a higher glucose conversion to glycerol. glycerol biosynthesis, fermentation, osmotolerant yeast, screening The work was supported by the State Assignment № AAAA-A20-120093090016-9 and the work was carried out using the Unique Scientific Facility of the "All-Russian Collection of Industrial Microorganisms" National Bio-Resource Center, NRC «Kurchatov Institute»---GOSNIIGENETIKA (NBC VKPM).

Studying of the polarization modes TE and TM for oblique incidence of light on thin films

Reflectance, absorbance and phase difference of the polarization modes (s-polarized) and (p-polarized) were described theoretically by using optical multilayers of thin films. A high reflectance layers with very low absorbance at different incident angles (0°,30°,60°,80°) can be achieved in the infrared region by adopting design(Air|HL|4 PbTe). High refractive index PbTe and low refractive index NaCl are used in the infrared region at central wavelength 10 µm. Design (Air|HL|3 Glass) adopted in the visible region by using TiO2 and CaF2 materials at central wavelength 550 nm. Spectral band width of reflectance remain large (7 µm-18 µm) for s-polarization with increases of the incident angles of the light, but spectral band width of reflectance for p-polarization are decreasing with an increase of the angles where the smallest for incident angle (80°) that reach (6.2 µm to 14 µm) due to increase of the phase shift between two modes of polarization. The absorbance of p-polarization has a larger value than the absorbance of s-polarization mode that causing a decrease in the reflectivity of the TM modes than TE modes.

Physiological and genomic analysis of newly-isolated polysaccharide synthesizing cyanobacterium Chroococcus sp. FPU101 and chemical analysis of the exopolysaccharide.

A unicellular cyanobacterium that produces a large amount of exopolysaccharide (EPS) was isolated. The isolate, named Chroococcus sp. FPU101, grew between 20 and 30°C and at light intensities between 10 and 80 μmol m-2 s-1. Purified EPS from Chroococcus sp. FPU101 had a molecular size of 5.9 × 103 kDa and contained galactose, rhamnose, fucose, xylose, mannose, glucose, galacturonic acid, and glucuronic acid at a molar ratio of 17.2:15.9:14.1:11.0:9.6:9.5:13.0:9.7. The EPS content significantly increased when the NaCl concentration in the medium was increased from 1.7 to 100 mM. However, high NaCl concentrations did not significantly affect the molecular size or chemical composition of the EPS. The genes wza, wzb, wzc, wzx, wzy, and wzz that are involved in EPS synthesis were conserved in the genome of Chroococcus sp. FPU101, which was sequenced in this study. These results suggest that the Wzy-dependent pathway is potentially involved in EPS production in this organism.

耐盐和盐敏感型小麦品种对NaCl胁迫的生理响应及耐盐性差异

为探究小麦品种类型对盐胁迫的生理响应及敏感性差异，以耐盐型品种济麦22和盐敏感型品种河农6425为材料，对幼苗期植株施以不同浓度的NaCl胁迫处理，比较分析了两个品种幼苗在胁迫条件下的生长、生理生化和叶绿体荧光特征等方面的差异。结果表明，NaCl胁迫对幼苗地上和地下部分的生长表现浓度依赖性的抑制效应，对耐盐型品种的抑制程度较小。在生理响应方面，幼苗体内的Na⁺含量随NaCl 浓度的增加而上升，K⁺和Ca²⁺含量则表现相反的变化趋势，耐盐型品种幼苗在胁迫处理前、后均具有较高的K⁺/Na⁺比和Ca²⁺/Na⁺比；NaCl胁迫导致幼苗的光系统Ⅱ受损，表现在Fv/Fm、Fv/Fo、qP 和YⅡ 等叶绿体荧光参数数值下降，降幅在耐盐性品种上相对较小。在氧化胁迫和抗氧化系统方面，NaCl胁迫导致幼苗体内活性氧水平的上升和过氧化物酶（POD）、过氧化氢酶（CAT）等抗氧化酶的响应；POD活性在处理后的0-12 d范围内呈先下降后上升的趋势，CAT活性则呈先上升后下降的趋势。耐盐品种的POD活性在胁迫早期受抑制时间较短，随后的响应更迅速且上升幅度更高；耐盐品种的CAT活性上升幅度更高，且在胁迫后期对高浓度NaCl和长时间胁迫导致的酶活性抑制的耐受性更强。耐盐品种抗氧化酶的这一响应特征与其较低的活性氧上升幅度一致，也与其较低水平的代表膜损伤程度的丙二醛（MDA）积累一致。耐盐型品种根部的MDA积累经200 mmol/L NaCl处理1 d后达到峰值，而盐敏感品种根部的MDA积累经150 mmol/L NaCl处理1 d后即达到峰值。以上研究结果表明，耐盐型小麦品种济麦22可分别通过其较强的K⁺/Na⁺、Ca²⁺/Na⁺调节能力和抗氧化酶体系缓解盐胁迫所导致的渗透胁迫和活性氧伤害，从而表现出耐盐的特征。;Soil salinity is a major abiotic stress inhibiting plant growth, development, and productivity, especially in case of crop. Wheat is an important cereal crop affected by high salinity. A better understanding of the physiological mechanisms underlying salt tolerance will facilitate efforts to improve crop performance under salinity. This study used two general wheat varieties as experimental materials to explore the growth physiological response and sensitivity difference of different cultivated wheat types to salt stress and their salt tolerance. Jimai 22 is salt-tolerant and Henong 6425 is salt-sensitive. In a hydroponic experiment, the effects of different concentrations (0, 50, 100, and 200 mmol/L) of NaCl stress on both Jimai 22 and Henong 6425 seedlings were investigated. The seedlings growth, salt tolerance index, main ion content, physiological and biochemical index, and chloroplast fluorescence parameters were compared. The results showed that NaCl stress inhibited the growth of aboveground and underground parts of wheat seedlings in a concentration dependent manner. The higher the concentration of NaCl was, the greater the toxicity on wheat seedlings would become. And the inhibition degree on Jimai 22 seedlings was smaller than that on Henong 6425 seedlings. In terms of physiological response, the Na⁺ contents in both Jimai 22 and Henong 6425 were increased with the increase of NaCl concentration, while the contents of both K⁺ and Ca²⁺ exhibited opposite trend of changing. The salt tolerance variety Jimai 22 had higher both K⁺/Na⁺ and Ca²⁺/Na⁺ before and after NaCl stress than those on salt sensitive Henong 6425. NaCl stress damaged the photosystem II of both Jimai 22 and Henong 6425 leaves. The concrete manifestation of damage effect was the decrease of chloroplast fluorescence parameters containing Fv/Fm, Fv/Fo, qP and YⅡ under different NaCl concentration. And the lowered range of these parameters in Jimai 22 induced by NaCl stress was lower than that in Henong 6425. In terms of oxidative stress and antioxidant system, the reactive oxygen species (ROS) level was increased with NaCl concentration stress increased. And the activities of peroxidase (POD) and catalase (CAT) were also changed. In 12 d after NaCl treatment, the POD activity was decreased firstly and then increased, while CAT activity was increased firstly and then decreased. The activities of both POD and CAT induced by NaCl stress in Jimai 22 were higher than those in Henong 6425. In the early stage of NaCl stress, the POD activity was temporally suppressed and the rising amplitude of POD activity was very large subsequently. The CAT activities induced by NaCl stress in Jimai 22 were higher than those in Henong 6425. In later days of NaCl stress, Jimai 22 had stronger tolerance to high NaCl concentration and inhibition of antioxidant system induced by long term NaCl stress. The rising range of antioxidant enzyme was consistent with lower ROS and lower malondialdehyde (MDA) which represents the degree of membrane damage in Jimai 22 under NaCl stress. The MDA content of salt tolerant Jimai 22 roots reached the peak after 200 mmol/L NaCl stress for 1 d. While the MDA content of salt sensitive Henong 6425 roots reached the peak after 150 mmol/L NaCl stress for 1 d. Overall, these results suggested that salt tolerant Jimai 22 had higher salt tolerance. Under NaCl stress, Jimai 22 can not only alleviate the damage of both active oxygen and osmotic stress due to the increasing activities of both POD and CAT, but also alleviate the ion stress by maintaining higher level of both K⁺/Na⁺ and Ca²⁺/Na⁺ after different concentrations of NaCl stress. Results from this study could be helpful for further understanding the physiological mechanism of severe NaCl stress in crop, and may be useful for elucidating the salt-tolerant mechanism of different cultivated crop types.

The Effects of Dry and Wet Grinding Processes on The Salt Quality

Studies were conducted on the salt quality, such as NaCl percent and whiteness achieved by dry and wet grinding methods. Crude solar salt is carefully collected from traditional solar salt ponds to ensure the uniformity of the sample. Several salt processing methods were applied in this research, such as washing, grinding, and dewatering by centrifuge hydro extractor and drying. The effect of reducing salt particle size to 0.6 and 0.25 mm was also studied. The dry grinding method is conducted before the washing stage, while the wet grinding method is applied after the washing stage. Both dry and wet grinding methods provide high-quality salt products, indicating high NaCl percent and whiteness. The dry grinding method produces higher NaCl percent and whiteness than the wet grinding method. However, the wet grinding method was better in water management and equipment durability with loss of salt losses during the washing stage. Finally, both grinding methods have advantages and disadvantages, so for developing the salt processing industry, both methods should be correctly chosen and match product output requirements.