Increasing Salt Concentration Research Articles

Influence of Soil Salinization on Active Layer Thickness of Frozen Soil

The climate of the Qinghai–Tibet Plateau is distinct. Given the large temperature difference between day and night, drought in perennial years, low rainfall and large evaporation volume, the frozen soil in some areas of the Qinghai–Tibet Plateau will occur in soil salt. The presence of salt in frozen soil salt changes the water thermal characteristics of the frozen soil, which will affect the changes in its activity layer. In this paper, the Beiluhe area of the Qinghai–Tibet Plateau was selected as the research object, and the numerical calculation model of water, heat and salt of salinised frozen soil was established. Considering the influence of salt crystallisation and salt on the freezing temperature of the active layer, the effects of different salt concentrations, water contents and salt type on the temperature of frozen soil and the thickness of the active layer were compared and analysed. Therefore, the salt of soil degenerates frozen soil under the action of sodium chloride and sodium sulphate, and the presence of sodium chloride and sodium sulphate is not conducive to the stability of frozen soil for many years. During soil salinisation, the content of sodium chloride in frozen soil increases; the temperature of permafrost initially decreases and then increases; the initial freezing time of the active layer is postponed in the freezing and cooling stages, the time when the water in the active layer with a salt concentration of 0.2–0.8% was delayed by 21, 32, 54 and 65 days; the temperature of the active layer decreases, which is the opposite in the thawing and heating stages, and the thickness of the active layer increases with the increase in salt concentration. During soil salinisation, the content of sodium sulphate in frozen soil increases; the freezing temperature of the active layer initially decreases and then increases and finally decreases, which is contrary to the temperature of the active layer in the warm season. The thickness of the active layer initially increases (with a maximum increase in 0.82 m) and then decreases and finally increases with the increase in salt concentration. The content of sodium sulphate in frozen soil has little effect on the initial freezing time of the active layer. High water content is conducive to the stability of permafrost. When the content of sodium chloride in frozen soil is constant, the water content increases; the temperature change of frozen soil is smaller; the temperature of the active layer in the warm season is lower; the thickness of the active layer is smaller, and the frozen soil tends to be more stable. When the content of sodium sulphate is constant, the increase in water content generally reduces the warm-season temperature of the active layer and the thickness of the active layer (−6 m the temperature of 30% and 40% water content in −6 m is 0.17 °C and 0.24 °C lower than that of 20% water content). However, analysis of the thickness of the active layer of the frozen soil containing sodium sulphate must combine the influence of water content and freezing temperature.

Impact of divalent ions on the conformations of single and double stranded DNA: A coarse-grained molecular dynamics study.

We developed a unified model to investigate the impact of physiologically relevant divalent ions Mg2+ and Ca2+ on conformations of double stranded DNA (dsDNA) and single-stranded DNA (ssDNA) in a background of monovalent ions Na+ and Cl-. We introduced explicit ions within the framework of coarse-grained three-interaction-site model (TIS-DNA) to take into account the direct interaction between the counterions and DNA. Simulations using the TIS-DNA model, we could quantitatively reproduce a number of experimental observables for both the dsDNA and ssDNA, without any adjustable parameters. We showed that divalent cations populate distinct conformations in different proportions, depending on the nucleotide sequence. With increase in salt concentration, an increased population of dA30 conformations with crooked helical motifs form while dT30 primarily populates collapsed-coil conformations.

Whey protein isolate nanofibrils formed with phosphoric acid: Formation, structural characteristics, and emulsion stability

In this study, phosphoric acid was used to replace hydrochloric acid which is widely reported in the production of whey protein isolate fibrils (WPF). The pH, temperature, and protein concentration for the phosphoric acid-induced fibrillation were optimized (4% w/v, pH 2.5, 90 °C). Under this condition, the mean particle size and molecular weight decreased significantly while the ζ-potential increased slightly, it suggested that the fibrillation was accompanied by hydrolysis. WPF was already formed via intermolecular interactions at 6 h, which exhibited a semiflexible and unbranched filament of about 10 nm in diameter. A few single-filament flexible fibrils (about 5 nm in diameter) formed at 24 h. Thioflavin T analysis supported by Intrinsic fluorescence showed that the use of phosphoric acid accelerated the fibrillation. The ANS fluorescence and Second-derivative UV–vis spectra indicated the increase in surface hydrophobicity, peaking after 12 h of heating. Compared with the hydrochloric acid induced, WPF induced by phosphoric acid exhibited a shorter lag phase and maintained a more stable dispersion state with a nanoscale particle size. The great interfacial properties and proper aspect ratio (length/diameter) provided the contribution that WPF effectively absorbed at the oil-water interface. Moreover, the emulsion stability of the WPF improved with increasing salt concentration. The phosphoric acid-induced WPF had the best emulsion stability at pH 5.5 which was further enhanced by proper heating. • The whey protein isolate fibrils (WPF) were formed via phosphoric acid. • The optimal preparation of WPF was at pH 2.5, 4%, 90 °C. • The surface hydrophobicity of WPF-12 (WPF formed at 12 h) reached the highest. • The WPF-12 exhibited excellent emulsion stability at pH 5.5.

Complexes of charged disordered polyelectrolyte-like proteins: From thermodynamics to stuctural plasticity.

The highly charged IDPs ProTα and H1 (−44 and +53, respectively) form a high-affinity, yet disordered complex and thus define a limiting case in the spectrum of disorder in IDP complexes [1-3]. Temperature-dependent single-molecule FRET (smFRET) experiments and isothermal titration calorimetry (ITC) reveal ProTα-H1 complexation to be enthalpically unfavorable. Using smFRET, we also identify stoichiometrically defined ternary complexes between ProTα and H1 at equilibrium and quantitate their salt-dependent stabilities, allowing us to accurately analyze ensemble experiments such as ITC performed with micromolar protein concentrations, where ternary complex formation is pronounced. Salt-dependent measurements show that counterion release entropy is a dominant driving force of complexation. An analytical polymer theory for polyelectrolyte complexation that explicitly accounts for counterions explains the thermodynamic results and suggests that the positive binding enthalpy is dominated by the relative exothermicities of counterion condensation and interchain ion-pair formation. Despite its high affinity, the disordered complex shows remarkable plasticity and expands continuously with increasing salt concentration, as seen from inter- and intramolecular FRET using various ProTα and H1 labeling variants. However, the salt-dependent expansion is non-uniform, which can be explained by differences in charge densities in different ProTα and H1 segments. Our investigations provide a comprehensive framework for the unconventional behavior of polyelectrolyte-like biomolecular complexes.

Quantifying Coupling Effects Between Soil Matric Potential and Osmotic Potential

AbstractSoil matric potential and osmotic potential are widely accepted as two independent components of total soil water potential. However, laboratory observations repeatedly demonstrated that matric potential can vary with salt concentration, implying a potential coupling between matric potential and osmotic potential. To date, it remains elusive whether matric potential and osmotic potential are independent or not and why so, and a theoretical theory for quantifying the coupling between them is still missing. Herein, a theoretical model is developed to quantitatively explain this problem via a lens provided by a recent concept of soil sorptive potential (SSP). The proposed model substantiates that matric potential and osmotic potential are not independent. The increasing salt concentration can notably depress two variables underpinning SSP, namely relative permittivity and electrical double layer thickness, leading to non‐negligible decreasing (more negative) of matric potential in the high suction range, and increasing (less negative) of it in the low suction range. In turn, the soil‐water interactions redistribute ions in soil water, raising osmotic potential especially for clay with high cation exchange capacity. The proposed model shows excellent performance in capturing experimental data, validating its accuracy. A parametric study implies that the neglection of coupling effects can lead to a significant underestimation of soil hydraulic conductivity in the film flow regime.

Saltiness enhancement: Impact of acid added to bread with heterogeneously distributed sodium chloride

The current global sodium consumption exceeds recommended daily intakes and there is a great need to reduce the sodium content in foods for a healthier society. The current study investigated the effect of combining sensory interaction principles and heterogeneous distribution of NaCl in bread on sensory properties, structure, and NaCl distribution. Breads were prepared in three different arrangements of NaCl distribution: homogenous, layered, and layered with lactic acid. Within each arrangement, four NaCl levels were tested. The breads were evaluated by a sensory panel for perceived saltiness, sourness, and qualitative texture, measured for stiffness, and the NaCl distribution was determined by X-ray fluorescence microscopy (XFM). Perceived saltiness was significantly enhanced in breads beyond heterogeneous NaCl distribution when lactic acid was added. Stiffness measurements were affected by layering of bread, the layers without NaCl were stiffer with an increase in overall salt concentration. The heterogeneous distribution of NaCl in layered breads could be visualised by XFM and textural consequences of layering bread are discussed. The current study demonstrates the potential of combining principles of pulsation of taste and sensory interactions together to enhance salt perception, and hence suggesting the approach as a possible further strategy for NaCl reduction in bread.

Effect of salt on solution behavior of spinning medium and properties of meat analogue fibers

Wet-spinning receives increasing interest as a potential method for mimicking natural animal muscle fibers. Here we systematically studied the effect of type and content of salt ions on the behavior of spinning solution composed of sodium alginate (SA) and soybean protein isolate (SPI), as well as the properties of meat analogue fibers. The properties of the composite spinning solution are first determined by adding salt ions, allowing for control over rheological chacracteristics. After wet-spinning, the SEM images illustrated higher salt content resulting in a more porous structure. FTIR proved the salt changed the secondary structure of the protein of the SA/SPI composite fibers. More importantly, increasing salt content could improve the juiciness of the meat analogue fibers by enhancing the water holding capacity and changing the moisture distribution. Generally, our work not only enriched the details of preparing meat analogue fibers based on plant proteins and polysaccharides by the wet-spinning method but also provided a theoretical reference for their industrial production.

Sodium chloride inhibits effective bubbly drag reduction in turbulent bubbly Taylor-Couette flows.

Using the Taylor-Couette geometry we experimentally investigate the effect of salt on drag reduction caused by bubbles present in the flow. We combine torque measurements with optical high-speed imaging to relate the bubble size to the drag experienced by the flow. Previous studies have shown that a small percentage of air (4%) can lead to dramatic drag reduction (40%). In contrast to previous laboratory experiments, which mainly used fresh water, we will vary the salinity fromthat of fresh water to the average salinity of ocean water. We find that the drag reduction is increasingly more inhibited for increasing salt concentrations, going from 40% for fresh water to just 15% for seawater. Salts present in the working fluid inhibit coalescence events, resulting in smaller bubbles in the flow and, with that, adecrease inthe drag reduction. Above a critical salinity, increasing the salinity has no further effect on thesize of bubbles in the flow and thus the drag experienced by the flow. Our new findings demonstrate the importance of sodium chloride on the bubbly drag reduction mechanism, and will further challenge naval architects to implement promising air lubrication systems on marine vessels. This article is part of the theme issue 'Taylor-Couette and related flows on the centennial of Taylor's seminal Philosophical Transactions paper (part 1)'.

The Effect of Alkali Iodide Salts in the Inclusion Process of Phenolphthalein in β-Cyclodextrin: A Spectroscopic and Theoretical Study.

The formation of the inclusion complex between β-cyclodextrin (CD) and phenolphthalein (PP) was investigated by means of UV-Vis and FT-IR spectroscopies. The thermodynamic parameters were calculated in the absence and presence of LiI, KI, NaI and CsI iodide salts. The enthalpy change during the formation was found to be negative for all solutions with iodide salts. The enthalpy change was found to decrease in the sequence no salt > NaI > KI> CsI > LiI. Moreover, it was observed that with increasing salt concentration enthalpy decreases monotonically. The interaction between the two molecules was mostly attributed to hydrogen bonding and Van der Waals interactions. Thermodynamic properties revealed that electrostatic forces also contribute when LiI is present in solutions. A molecular docking study was performed to elucidate the docking between phenolphthalein and cyclodextrin. The FT-IR spectra of CD, PP and the CD-PP complex were recorded to establish the formation of the inclusion complex. Semi-empirical and DFT methods were utilized to study theoretically the complexation process and calculate the IR vibrational spectra. The adequate agreement between theoretical and experimental results supports the proposed structural model for the CD-PP complexation.

Bioaccessibility of per- and polyfluoroalkyl substances in food and dust: Implication for more accurate risk assessment

Humans are exposed to per- and polyfluoroalkyl substances (PFASs) mainly through oral exposure route, while little is known about their bioaccessibility (BC) in oral matrices. Here, the BC of 13 PFASs in simulated vegetable (VFs) and animal foods (AFs) as well as indoor dust was investigated using a physiology-based extraction test. The BC of PFASs in the AFs (78.5 ± 13.6 %) was distinctly higher than that in the VFs (60.6 ± 13.4 %), because high-saturated and long-chain fatty acids in the animal fat favored formation of more stable micelles. The BC of most long-chain PFASs was positively correlated with the protein content while negatively correlated with the carbohydrate content in the foods. The BC of polyfluoroalkyl phosphate diesters was negatively correlated with the lipid content. The BC of the very long-chain PFASs in the foods was 2.42–6.02 times higher than that in the dust, which might be attributed to their strong sequestration in dust. With the increase in bile salt concentration, the BC of PFASs in food increased and then remained constant, which was related to the changes in fatty acids and stability of the formed micelles. Comparing with the previous results obtained from animal study, the BC obtained in this study has the potential to predict PFAS bioavailability in food.

Strengthening Polylactic Acid by Salification: Surface Characterization Study.

Polylactic acid (PLA) is one of the market's most commonly used biodegradable polymers, with diverse applications in additive manufacturing, specifically fused deposition modeling (FDM) 3D printing. The use of PLA in complex and sophisticated FDM applications is continually growing. However, the increased range of applications requires a better understanding of the material properties of this polymer. For example, recent studies have shown that PLA has the potential to be used in artificial heart valves. Still, the durability and longevity of this material in such a harsh environment are unknown, as heart valve failures have been attributed to salification. Additionally, there is a gap in the field for in situ material characterization of PLA surfaces during stiffening. The present study aims to benchmark different dynamic atomic force microscopy (AFM) techniques available to study the salification phenomenon of PLA at micro-scales using different PLA thin films with various salt concentrations (i.e., 10%, 15%, and 20% of sodium chloride (NaCl)). The measurements are conducted by tapping mode AFM, bimodal AFM, the force spectroscopy technique, and energy quantity analysis. These measurements showed a stiffening phenomenon occurring as the salt solution is increased, but the change was not equally sensitive to material property differences. Tapping mode AFM provided accurate topographical information, while the associated phase images were not considered reliable. On the other hand, bimodal AFM was shown to be capable of providing the topographical information and material compositional mapping through the higher eigenmode's phase channel. The dissipated power energy quantities indicated that how the polymers become less dissipative as salt concentration increases can be measured. Lastly, it was shown that force spectroscopy is the most sensitive technique in detecting the differences in properties. The comparison of these techniques can provide a helpful guideline for studying the material properties of PLA polymers at micro- and nano-scales that can prove beneficial in various fields.

Power Generation by Halophilic Bacteria and Assessment of the Effect of Salinity on Performance of a Denitrifying Microbial Fuel Cell

Saline wastewater pollution is a critical issue that needs to be addressed. The present study focused on the development of a dual-chambered microbial fuel cell (MFC) treating saline wastewater at the anode. Halophilic exo-electrogenic bacteria enriched from seawater (Arabian Sea, Mumbai, India) were used in the anodic chamber of the MFC. Denitrification using denitrifying bacteria was employed in the cathodic chamber. The maximum power density was significantly increased from 96.77 mW/m2 to 162.09 mW/m2 with a rise in NaCl concentration from 20 to 40 g/L. Nitrate removal in the cathode chamber increased from 80 ± 3% to 89 ± 3.2% with increase in salt concentration from 20 g/L to 40 g/L and concomitantly COD removal in the anode chamber increased from 76 ± 3.8% to 83 ± 4%. Cyclic voltammetry (CV) analysis revealed higher electrochemical activity at 40 g/L salt concentration. Electrochemical impedance spectroscopy (EIS) analysis exhibited that charge transfer and solution resistances were lower when the salinity was increased. Microbial community analysis revealed the presence of Clostridium, Shewanella, and Bacillus as the most abundant genera in the anodic chamber. This study demonstrated the dual applicability of the system targeted for removal of organics from saline wastewater and nitrate removal from contaminated wastewater accompanied by power generation from the MFC.

Response of Pea Plants (Pisum sativum cv. Ran 1) to NaCl Treatment in Regard to Membrane Stability and Photosynthetic Activity.

Salinity is one of the most extreme abiotic stress factors that negatively affect the development and productivity of plants. The salt-induced injuries depend on the salt tolerance of the plant species, salt concentration, time of exposure and developmental stage. Here, we report on the response of pea plants (Pisum sativum L. cv Ran 1) to exposure to increasing salt concentrations (100, 150 and 200 mM NaCl) for a short time period (5 days) and the ability of the plants to recover after the removal of salt. The water content, membrane integrity, lipid peroxidation, pigment content and net photosynthetic rate were determined for the pea leaves of the control, treated and recovered plants. Salt-induced alterations in the primary photosynthetic reactions and energy transfer between the main pigment-protein complexes in isolated thylakoid membranes were evaluated. The pea plants were able to recover from the treatment with 100 mM NaCl, while at higher concentrations, concentration-dependent water loss, the disturbance of the membrane integrity, lipid peroxidation and an increase in the pigment content were detected. The net photosynthetic rate, electron transport through the reaction centers of PSII and PSII, activity of PSIIα centers and energy transfer between the pigment-protein complexes were negatively affected and were not restored after the removal of NaCl.

Effects of parental age on salt stress tolerance in an aquatic plant

Parental age influences components of offspring fitness in many species. The ability to tolerate stress also affects fitness, but less is known regarding changes in offspring stress tolerance with increasing parental age, especially in plants. We examined first and fifth‐born clonal offspring (using birth order as a proxy for parental age), and compared their fitness in several sub‐lethal concentrations of salt (NaCl), to investigate the interactive effects of birth order and salt stress on the offspring of the aquatic plant Lemna minor L. We found that increasing salt concentration reduced reproduction particularly at early ages, which detrimentally affected fitness, as measured by the intrinsic rate of natural increase. Fifth offspring had greater fitness than first offspring, potentially due to the hump‐shaped relationship between offspring fitness and birth order observed in other studies on Lemna, with fifth offspring near the peak of the hump. We found no interactive effect of birth order and salt concentration on offspring fitness; however, there were interactive effects on the time to first reproduction and the size of fronds. Specifically, first offspring exposed to increasing salt concentrations exhibited longer delays to first reproduction and grew to a greater size, while fifth offspring showed little change in either variable with increasing salt concentration. Thus, variation in birth order affected offspring response to salt stress, although not in terms of fitness. These results help illuminate factors impacting the age‐specific strength of natural selection and stress responses, and may be environmentally relevant in the context of environmental salinization.

Influence of mineral composition on nano-interfacial adhesion of asphalt mixtures exposed to chloride salt erosion

As a common pavement deicing salt, sodium chloride has adverse effects on asphalt pavement. In this study, molecular modeling methods were used to analyze the effects of mineral composition and chloride salt erosion on the interfacial adhesion properties of asphalt-aggregate composites. Four representative asphalts (AAA-1, AAK-1, AAM-1, and AAF-1), three representative minerals (α-quartz, calcium carbonate, and alumina), and sodium chloride solutions were selected to model the asphalt-aggregate composites exposed to chloride salt erosion. The effects of asphalt type, mineral composition, salt concentration, and erosion temperature on the interface adhesion of the asphalt mixture were considered. The chloride salt erosion resistance of the four components and asphalt molecules were further analyzed. The simulation results indicate that the effect of erosion temperature on the interfacial adhesion performance is minor. The interfacial adhesion decreased with the increase in chloride salt concentration. Alkaline minerals are more susceptible to chloride salt erosion, followed by neutral and acidic minerals. The adhesion energies of resin and aromatic decreased most significantly in alkaline minerals, followed by neutral minerals, and the least decreased in acidic minerals exposed to chloride salt erosion. Asphalt molecules with more aromatic rings, shorter alkyl side chains, and stronger polarity have strong resistance to chloride salt erosion and can form strong adsorption with the active sites on the mineral surface. However, asphalt molecules with long-chain alkanes, fewer aromatic rings, or longer alkyl side chains are difficult to resist chloride salt erosion.

ВИЗНАЧЕННЯ ЕФЕКТИВНОСТІ ВИЛУЧЕННЯ СУЛЬФАТІВ НА ЗВОРОТНООСМОТИЧНІЙ МЕМБРАНІ НИЗЬКОГО ТИСКУ

The dependence of the efficiency of the low-pressure reverse osmosis membrane Filmtec TW30-1812-50 on the initial concentrations of sodium sulfate in the range of 10-650 mg/dm3 at permeate recovery rates of 1-90 % using a pressure of 4 atm was determined. The effect of increasing the permeate recovery rate on selectivity, membrane performance, and the in-crease in the sulfate content of concentrates was determined. It is shown that the concentration of sulfates in permeate depends on their initial concentration in solutions and increases both with an increase in the initial concentration and with an increase in the degree of permeate extraction. The latter factor is quite significant at initial sulfate concentrations of 650 mg/dm3. The membrane performance increases with decreasing salt content in water and decreases with increasing permeate removal rate, which leads to an increase in salt concentration in the pre-membrane space. The selectivity of the membrane for sulfates is 94.9-99.3 % and increases with increasing concentration of sodium sulfate solutions in solutions, despite a certain increase in salt concentrations in permeates. It is shown that as the degree of permeate selection increases, the selectivity for solutions with low initial sulfate concentrations increases. A FFP-based process modeling was performed to determine the sulfate con-centration in the permeate and concentrate at any initial sulfate concentration in a certain range. It was found that the con-centrate solutions are stable in the entire range of concentrations used with an increase in the degree of permeate recovery from 10 to 90 %. Based on the research results, a method for determining the capacity of the plant and the osmotic and oper-ating pressures based on the salt concentration and the set pressure in the system was proposed. From the data obtained, it can be concluded that the permissible level of mineralization at which the use of low-pressure reverse osmosis membranes is ad-visable.

The role of ion solvation in lithium mediated nitrogen reduction.

Since its verification in 2019, there have been numerous high-profile papers reporting improved efficiency of lithium-mediated electrochemical nitrogen reduction to make ammonia. However, the literature lacks any coherent investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrolyte Interphase (SEI) properties. In this study, we discover that the salt concentration has a remarkable effect on electrolyte stability: at concentrations of 0.6 M LiClO4 and above the electrode potential is stable for at least 12 hours at an applied current density of -2 mA cm-2 at ambient temperature and pressure. Conversely, at the lower concentrations explored in prior studies, the potential required to maintain a given N2 reduction current increased by 8 V within a period of 1 hour under the same conditions. The behaviour is linked more coordination of the salt anion and cation with increasing salt concentration in the electrolyte observed via Raman spectroscopy. Time of flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy reveal a more inorganic, and therefore more stable, SEI layer is formed with increasing salt concentration. A drop in faradaic efficiency for nitrogen reduction is seen at concentrations higher than 0.6 M LiClO4, which is attributed to a combination of a decrease in nitrogen solubility and diffusivity as well as increased SEI conductivity as measured by electrochemical impedance spectroscopy.

盐和重金属复合胁迫对翅碱蓬萌发与生长的影响及调控措施

PDF HTML阅读 XML下载 导出引用 引用提醒 盐和重金属复合胁迫对翅碱蓬萌发与生长的影响及调控措施 DOI: 10.5846/stxb202107141901 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家水体污染控制与治理科技重大专项(2018ZX07601-003); 国家自然科学基金项目(41501551) Effects of combined stress of salt and heavy metals on germination and growth of Suaeda salsa and regulation measures Author: Affiliation: Fund Project: Supported by the Major Science and Technology Program for Water Pollution Control and Treatment (No. 2018ZX07601-003),National Natural Science Foundation of China（41501551） 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探究Zn、Cu与盐复合胁迫对翅碱蓬(Suaeda salsa)萌发生长的影响机理及其调控措施,以翅碱蓬为研究对象,采用水培试验方法,测定Zn、Cu和盐复合胁迫条件下翅碱蓬种子发芽率、萌发速率和幼苗渗透调节物质含量等指标,分析1.5 mg/L吲哚乙酸(IAA)、100 mg/L 赤霉素(GA)和0.3% 硝酸钾(KNO3)处理对Zn、Cu与盐复合胁迫条件下翅碱蓬萌发与生长的影响。结果表明:(１) Zn、Cu与高盐复合胁迫极显著降低翅碱蓬种子的发芽率,中高浓度的Zn、Cu与盐复合胁迫极显著降低翅碱蓬种子的萌发速率,Zn、Cu和盐复合胁迫对翅碱蓬种子的萌发生长影响表现为低促高抑效应,影响因子间存在明显的协同效应;(2)Zn、Cu和盐复合胁迫条件下,随着盐浓度的升高,翅碱蓬幼苗体内过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)3种抗氧化酶活性呈先升高后降低的变化趋势,Zn、Cu和高盐复合胁迫使翅碱蓬幼苗体内丙二醛(MDA)含量增加近2.5倍;(３)1.5 mg/L IAA溶液浸种12 h可显著提高Zn、Cu与高盐复合胁迫条件下翅碱蓬种子的发芽率和萌发速率,降低翅碱蓬幼苗MDA含量,显著增强其POD和CAT活性,从而降低复合胁迫对翅碱蓬的伤害,但不能完全消除复合胁迫的影响。建议在Zn、Cu与高盐复合胁迫条件下翅碱蓬补种前应用1.5 mg/L IAA溶液浸种12 h,提高翅碱蓬湿地生态修复效率。 Abstract:To explore the influence mechanism and regulation measures of the combined stress of Zn, Cu, and salt for the germination and growth of Suaeda salsa, Suaeda salsa was taken as the research object of this paper. Taking the method of hydroponic experiment, the germination percentage, germination rate and osmotic adjustment substance content of Suaeda salsa seeds under the combined stress of Zn, Cu and salt were determined. The effects of 1.5 mg/L indoleacetic acid (IAA), 100 mg/L gibberellin (GA) and 0.3% potassium nitrate (KNO3) on the germination and growth of Suaeda salsa under the combined stress of Zn, Cu and salt were studied. The results showed that: (1) the combined stress of Zn, Cu, and high concentration salt could significantly reduce the germination percentage of seeds of Suaeda salsa. The combined stress of Zn, Cu, and salt with the medium and high concentrations could significantly inhibit the germination rate of seeds of Suaeda salsa. The effect of Zn, Cu and salt combined stress on the germination and growth of Suaeda salsa seeds showed the effect of low concentration promotion and high concentration inhibition. There were obviously synergistic effects among the influencing factors. (2)The activity of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) in Suaeda salsa seedlings increased first and then decreased with the increase of salt concentration under the combined stress condition of the treatment of Zn, Cu, and salt. The content of malondialdehyde (MDA) in Suaeda salsa seedlings increased by nearly 2.5 times under the combined stress condition of Zn, Cu, and high concentration salt. (3)The 1.5 mg/L IAA solution for 12 h could significantly increase the germination percentage and germination rate of seeds under the combined stress of Zn, Cu, and excess salt, reduce the MDA content and significantly enhance the activity of POD and CAT, thereby reducing the damage of the combined stress to Suaeda salsa. It is suggested that under the combined stress of Zn, Cu and high salt, seeds of Suaeda salsa should be soaked in 1.5 mg/L IAA solution for 12 hours before replanting in coastal degraded wetland to improve the ecological restoration efficiency of Suaeda salsa wetland. 参考文献 相似文献 引证文献

The relationship between bacterial outer membrane vesicles and halophilic adaptation.

Many cells are known to actively release nano-sized outer membrane vesicles (OMVs) that contain bioactive proteins, lipids, and nucleic acids into the extracellular environment. These vesicles have been associated with adaptation to environmental stress in other species, but their role in halophilic salt stress adaptation is not known. This study aimed to isolate and characterize the OMVs of Halomonas caseinilytica KB2 at various salt concentrations [6% (KB2-6), 12% (KB2-12), and 18% (KB2-18)] and to identify the patterns of adaptations to increasing salinity in its structure, protein composition, and expression. Also, a comparison with the composition of OMVs of E. coli, a mesophilic bacterium, was performed. Bioinformatics and statistical analysis were carried out to elucidate the underlying proteome differences that may exist as a result of increasing salinity. The results show that OMV production in H. caseinilytica KB2 is promoted by a decrease in salinity. OMVs also revealed possible structural and metabolic changes happening in the cells which led to the deduction that cells become more stable with increasing salt concentrations. Cell wall integrity, protein expression and folding are important. Although H. caseinilytica KB2 OMVs show cellular changes with changing salt concentration, they may not play a direct role in adaptation to changing salinity.

Unraveling fluctuation in gelatin and monovalent salt systems: coulombic starvation.

Fluctuations play a key role in biological systems. Here, fluctuations in gelatin intensify with increasing salt concentration. We find a redistribution of hydrogen bonds in protein-salt systems due to unfulfilled hydration of the charges of gelatin and salt-ions, termed as coulombic starvation. This yielded three regions; no starvation, starvation of gelatin, and both gelatin-salt. The system reaches equilibrium with all charges being partially hydrated. This will aid in interpreting protein-metal ion interactions and designing biomaterials.