Saline Conditions Research Articles

Experimental Study on Impedance Spectrum-Based Detection of Water Holdup in Two-Phase Flow under Complex Salinity Conditions

Experimental Study on Impedance Spectrum-Based Detection of Water Holdup in Two-Phase Flow under Complex Salinity Conditions

Investigating functional mechanisms in the Co-biodegradation of lignite and guar gum under the influence of salinity

The biodegradation of guar gum by microorganisms sourced from coalbeds can result in low-temperature gel breaking, thereby reducing reservoir damage. However, limited attention has been given to the influence of salinity on the synergistic biodegradation of coal and guar gum. In this study, biodegradation experiments of guar gum and lignite were conducted under varying salinity conditions. The primary objective was to investigate the controlling effects and mechanisms of salinity on the synergistic biodegradation of lignite and guar gum. The findings revealed that salinity had an inhibitory effect on the biomethane production from the co-degradation of lignite and guar gum. The biomethane production declined with increasing salinity levels, decreasing from 120.9 mL to 47.3 mL. Even under 20 g/L salt stress conditions, bacteria in coalbeds could effectively break the gel and the viscosity decreased to levels below 5 mPa s. As salinity increased, the removal rate of soluble chemical oxygen demand (SCOD) decreased from 55.63% to 31.17%, and volatile fatty acids (VFAs) accumulated in the digestion system. High salt environment reduces the intensity of each fluorescence peak. Alterations in salinity led to changes in microbial community structure and diversity. Under salt stress, there was an increased relative abundance of Proteiniphilum and Methanobacterium, ensuring the continuity of anaerobic digestion. Hydrogentrophic methanogens exhibited higher salt tolerance compared to acetoclastic methanogens. These findings provide experimental evidence supporting the use of guar gum fracturing fluid in coalbeds with varying salinity levels.

Vertical non-uniform distribution of soil salinity enhances nitrogen utilization efficiency and influences δ15N distribution in tomato plants

Soil salinity typically exhibits non-uniform distribution in the natural environment. However, how vertically non-uniform distribution of soil salinity in the root zone (VNDSR) regulated plant nitrogen metabolism is still largely elusive. This study aimed to investigate the impact of VNDSR on leaf Malondialdehyde (MDA) content, upper and lower root activity, leaf Na+/Ca2+ and Na+/K+, various tomato organs’ nitrogen concentration (%) and natural abundance of nitrogen isotopes (δ15N,‰), and nitrogen utilization efficiency of tomato plants. Four treatments were established, including the upper layer of the root zone having soil salinity levels of 1 ‰, 1 ‰, 2 ‰, and 3 ‰, while the corresponding lower layer of the root zone had soil salinity levels of 1 ‰, 5 ‰, 4 ‰, and 3 ‰, respectively, denoted as T1:1, T1:5, T2:4, and T3:3. The results showed that under the same average soil salinity conditions and compared to the treatment with uniform soil salinity distribution in the root zone (T3:3), the VNDSR treatment (T1:5) significantly reduced leaf MDA content (p < 0.01), Na+/Ca2+ (p < 0.01) and Na+/K+ (p < 0.01), and stem δ15N values (p < 0.05). Moreover, the VNDSR treatment (T1:5) significantly increased the ratio of upper and lower root biomass-weighted root activity (p < 0.01), tomato fruit yield (p < 0.01), and nitrogen partial factor productivity (PFP, gg−1, p < 0.01) compared to uniform salt distribution treatment (T3:3). There were significant positive correlations (p < 0.05) between leaf δ15N values and Nitrogen Absorption Ratio (NAR, %, p < 0.05) and PFP (p < 0.05), indicating that under VNDSR, δ15N values can serve as an indicator that comprehensively reflects the information of plant nitrogen utilization efficiency. In conclusion, the VNDSR could mitigate the damage of salt stress to tomatoes, enhance plant nitrogen uptake and utilization efficiency, and promote the growth and development of tomatoes. Data AvailabilityThe datasets generated or analyzed during the current study are available from the corresponding author on reasonable request.

Growth Pattern and Survival of Mangrove Seedlings on the Coast of Peunaga Cut Ujong, West Aceh

Mangroves are coastal ecosystems with different abilities to adapt to changing environmental conditions. Habitat characteristics that continue to change cause morphological, anatomical, and physiological adaptations of mangrove species. This study aims to observe the survival and growth rate of Rhizhopora mucronata in Peunaga Cut Ujong, Meurebo, West Aceh. The mangroves were planted in 2022 and observed one year after planting. The observation and data collection of 35 tree samples were conducted every two weeks. The results showed a decrease in the survival rate from the third month of observation until the end, showing a decrease of 78%. In contrast, tree growth increased from months 1 to 5. Salinity conditions and substrates dominated by sand with minimal nutrients indicate adaptation to the growth of some relatively small mangrove species. Fluctuating salinity conditions with the dominance of sand have the potential to support the survival of R. mucronata, although with low growth. Its main influence still needs to be studied over a longer period. Keywords: adaptations, growth, morphometrics, salinity

Effects of High Salinity and Water Stress on Wetland Grasses from the Spanish Mediterranean Coast.

The impacts of climate change are reaching unprecedented levels, heightening the risk of species loss and ecosystem service degradation. Wetlands, highly threatened ecosystems, serve vital ecological functions by capturing carbon, filtering water, and harbouring diverse wildlife. Coastal wetlands encounter many challenges, such as increased drought periods and escalating salinity levels, severely impacting plant biodiversity. Assessing how plants respond to various environmental stress factors is imperative for devising successful conservation strategies. In the present study, we examined three representative grass species found in various habitats within the Albufera Natural Park, close to the city of Valencia on the Spanish Mediterranean coast: Imperata cylindrica, Phragmites australis, and Saccharum ravennae. High salinity and water stress conditions were induced by subjecting the plants to irrigation with solutions containing 200, 400, 600, and 800 mM NaCl or withholding irrigation altogether to mimic coastal flooding and drought scenarios. The treatments were maintained until noticeable wilting of the plants occurred, at which point a range of stress biomarkers were determined, including photosynthetic pigments, ions, osmolytes, oxidative stress markers, and antioxidant metabolites, as well as antioxidant enzyme activities. Saccharum ravennae displayed the highest sensitivity to salt stress, whereas I. cylindrica appeared to be the most tolerant. The primary salinity tolerance mechanism observed in I. cylindrica and P. australis was a blockage of ion transport from the root zone to the aerial part, together with the salt-induced accumulation of proline and soluble sugars to high concentrations in the former. No significant effects of the water deficit treatment on the growth or biochemical parameters were observed for any of the analysed species. These findings offer valuable information for the effective management and conservation of coastal wetlands facing the challenges posed by climate change.

Plasma Electrolytes Response in Mud Catfish, Clarias gariepinus (Burchell 1822) exposed to Different Regimes of Salinity and pH

Introduction: Aquatic organisms, especially fish, are highly sensitive to environmental changes that can profoundly affect their physiological processes essential for survival. Physico-chemical factors such as salinity and pH exert significant influences on osmoregulation and ion balance, which are critical for maintaining cellular homeostasis in fish. Aims: This study aims to explore how varying levels of salinity and pH affect plasma electrolyte concentrations in Clarias gariepinus, focusing on potassium (K+), sodium (Na+), chloride (Cl−), and bicarbonate (HCO3−) ions. The objective is to understand the physiological responses of C. gariepinus to these environmental factors and their potential as biomarkers for assessing aquatic ecosystem health. Materials and Methods: Juvenile C. gariepinus was exposed to different salinity levels (4 ‰, 6 ‰, 8 ‰) and pH levels (4, 6, 8) over 21 days. Plasma electrolyte concentrations were measured using an SFRI ISE 6000 Electrolyte Analyser. Statistical analysis included ANOVA and DMRT to identify significant differences (p &lt; 0.05) among experimental groups. Results: The study found significant variations in K+, Cl−, Na+, and HCO3- concentrations in C. gariepinus across different salinity and pH conditions. K+ levels decreased with increasing salinity, indicating stress-induced responses, while pH variations had less pronounced effects on K+ regulation. Cl− concentrations increased with higher salinity levels, suggesting adaptive osmoregulatory strategies. Na+ levels showed significant fluctuations across salinity and pH conditions, whereas HCO3− levels responded uniquely to changes in these parameters, demonstrating adaptive mechanisms in acid-base balance. Conclusion: This research underscores the adaptive responses of C. gariepinus to fluctuations in salinity and pH, highlighting their ability to maintain plasma electrolyte balance under varying environmental conditions. These findings contribute to understanding the ecophysiological adaptations of C. gariepinus and suggest the potential utility of plasma electrolytes as biomarkers for assessing the health of aquatic ecosystems.

Rhizobacteria associated with Parkinsonia aculeata L. under semi desertic drought and saline conditions

Rhizobacteria associated with Parkinsonia aculeata L. under semi desertic drought and saline conditions

In situ measurement of the three-dimensional distribution of labile copper in sediment pore water using a microneedle sensor with nanoporous structure

Conventional ex situ analytical methods for sediment pore water are susceptible to disruptions in the speciation equilibrium of metals due to changes in external conditions. This study introduced an innovative in situ method for detecting the three-dimensional distribution of labile copper (CuLabile) in sediment pore water with high spatial resolution using a highly stable microneedle electrochemical sensor. The sensor featured a nanoporous tip structure and embedded gold nanomaterials with excellent electrocatalytic performance. The nanoporous structure could prevent the nanomaterials from falling off because of friction during the in situ detection process in sediments. The sensor exhibited good detection performance under different salinity conditions with a detection limit of 0.2 nM. Vertical and three-dimensional distributions of CuLabile in sediment pore water were successfully obtained using the in situ microneedle sensor. The results showed that the concentration of CuLabile was in the range of 5.2–43.5 nM, with a maximum value at a depth of approximately 4 cm, while there was almost no difference in the horizontal direction of a specific sediment sample column. Furthermore, this functional sensor could be extended to the in situ detection of other labile metals in sediment pore water.

Integrated biofloc technology in red tilapia aquaculture: Salinity-dependent effects on water quality, parental stock physiology, reproduction, and immune responses

The study examines the impact of integrated biofloc technology (BFT), different salinity levels, and their combined effects over 90 days on various physiological parameters. The investigation includes growth performance and feed utilization, water quality, the chemical composition of biofloc and fish, digestive enzymes, reproductive performance, stress and biochemical indicators, and antioxidant-immune responses in red tilapia (Oreochromis spp.) broodstock. The fish were initially weighed (males: n = 270; 104 ± 0.96 g; females: n = 270; 93.2 ± 0.66 g) and subsequently divided into 12 treatment groups (6 for males and 6 for females) spread across 36 separate tanks (3 tanks per treatment; 45 fish per treatment; 15 fish/tank). The treatments involved three salinity levels (18, 28, and 36 ppt) in both clear water (CW) and BFT systems. The outcomes demonstrated that fish in the 36 ppt salinity with BFT treatment demonstrated significant improvements (P < 0.05) in growth parameters (final body weight, weight gain, and specific growth rate, feed intake, and feed conversion ratio). The condition factor in BFT groups increased in all salinity situations. The survival rates of broodstock were consistently high in all experimental conditions The study found that BFT and salinity significantly impacted (P < 0.05) whole body contents (moisture, protein, lipid, and ash) in both males and females. Water quality parameters showed variations between BFT and CW, with notable impacts (P < 0.05) on dissolved oxygen and pH. The BFT and salinity influenced digestive enzyme activities (protease, amylase, and lipase) and reproductive performance (males) and the 36 ppt salinity with BFT recorded the highest values. The hemato-biochemical and antioxidant-immune responses were also impacted by BFT and salinity exposure. The study highlights the potential benefits of incorporating BFT into red tilapia aquaculture systems, particularly in optimizing growth, health, and reproductive performance under various salinity conditions, which can enhance sustainable intensification, disease control, and environmental stewardship.

Characterization of Exopolysaccharides Having Potential Antiviral Properties from Priestia Aryabattai Strain MK1 and Bacillus sp. Strain MK2.

Viral diseases are a serious threat to humans while themost antiviral drugs have low efficiency and side effects on human health. Therefore, using microbial biopolymers as the drugs alternate to treat viral infections seems cost-effective and human friendly option. In the present study, thirty-four exopolysaccharides (EPSs) producing bacteria were isolated, and EPSs production capacity of five salt-tolerant isolates was determined under 0, 100 and 150 mM NaCl. Among these, two isolates exhibiting high anti-coliphage activity were identified through 16S rRNA gene analysis. Moreover, the EPSs were characterized by Fourier-transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) analysis, and their composition was determined. Five salt-tolerant bacteria (MK1, MK2, MK10, MK22 and MK29) exhibited higher production of EPSs at 100 mM NaCl compared to that under non-saline control. At 100 mM NaCl, the yield of EPSs ranged between 105 and 330mg 100 mL-1 broth. The EPSs produced by the isolates MK1 and MK2 exhibited higher anti-coliphage activity (plaque forming unit decreased from 43 × 106 mL-1 to 3 × 106 and 4 × 106 mL-1, respectively), and were comprised of glucose, fructose, galactose, sucrose, lactose and xylose sugars. FTIR spectroscopy depicted that EPSs are mainly composed of hydroxyl, aliphatic, carboxyl, sulfate and phosphate functional groups, which could have bound coliphage and thus conferred higher anti-coliphage activities to the EPSs. Phylogenetic analysis revealed that MK1 and MK2 isolates formed clades within genus Priestia and Bacillus sequences, respectively. High EPSs production capacity of bacterial isolates under saline condition and high anti-coliphage activity of the EPSs implies that bacterial biopolymers could be useful in antiviral drugs therapy.

Detection of closely linked QTLs and candidate genes controlling germination indices in response to drought and salinity stresses in barley

The aim of current study was to identify closely linked QTLs and candidate genes related to germination indices under control, salinity and drought conditions in barley. A total of nine (a major), 28 (eight major) and 34 (five major) closely linked QTLs were mapped on the seven chromosomes in response to control, drought and salinity conditions using genome-wide composite interval mapping, respectively. The major QTLs can be used in marker-assisted selection (MAS) projects to increase tolerance to drought and salinity stresses during the germination. Overall, 422 unique candidate genes were associated with most major QTLs. Moreover, gene ontology analysis showed that candidate genes mostly involved in biological process related to signal transduction and response to stimulus in the pathway of resistance to drought and salinity stresses. Also, the protein–protein interaction network was identified 10 genes. Furthermore, 10 genes were associated with receptor-like kinase family. In addition, 16 transcription factors were detected. Three transcription factors including B3, bHLH, and FAR1 had the most encoding genes. Totally, 60 microRNAs were traced to regulate the target genes. Finally, the key genes are a suitable and reliable source for future studies to improve resistance to abiotic stress during the germination of barley.

Extremozymes and compatible solute production potential of halophilic and halotolerant bacteria isolated from crop rhizospheric soils of Southwest Saurashtra Gujarat

Halophiles are one of the classes of extremophilic microorganisms that can flourish in environments with very high salt concentrations. In this study, fifteen bacterial strains isolated from various crop rhizospheric soils of agricultural fields along the Southwest coastline of Saurashtra, Gujarat, and identified by 16S rRNA gene sequencing as Halomonas pacifica, H. stenophila, H. salifodinae, H. binhaiensis, Oceanobacillus oncorhynchi, and Bacillus paralicheniformis were investigated for their potentiality to produce extremozymes and compatible solute. The isolates showed the production of halophilic protease, cellulase, and chitinase enzymes ranging from 6.90 to 35.38, 0.004–0.042, and 0.097–0.550 U ml−1, respectively. The production of ectoine-compatible solute ranged from 0.01 to 3.17 mg l−1. Furthermore, the investigation of the ectoine-compatible solute production at the molecular level by PCR showed the presence of the ectoine synthase gene responsible for its biosynthesis in the isolates. Besides, it also showed the presence of glycine betaine biosynthetic gene betaine aldehyde dehydrogenase in the isolates. The compatible solute production by these isolates may be linked to their ability to produce extremozymes under saline conditions, which could protect them from salt-induced denaturation, potentially enhancing their stability and activity. This correlation warrants further investigation.

Recent Advances in Geochemical and Mineralogical Studies on CO2–Brine–Rock Interaction for CO2 Sequestration: Laboratory and Simulation Studies

The urgent need to find mitigating pathways for limiting world CO2 emissions to net zero by 2050 has led to intense research on CO2 sequestration in deep saline reservoirs. This paper reviews key advancements in lab- and simulation-scale research on petrophysical, geochemical, and mineralogical changes during CO2–brine–rock interactions performed in the last 25 years. It delves into CO2 MPD (mineralization, precipitation, and dissolution) and explores alterations in petrophysical properties during core flooding and in static batch reactors. These properties include changes in wettability, CO2 and brine interfacial tension, diffusion, dispersion, CO2 storage capacity, and CO2 leakage in caprock and sedimentary rocks under reservoir conditions. The injection of supercritical CO2 into deep saline aquifers can lead to unforeseen geochemical and mineralogical changes, possibly jeopardizing the CCS (carbon capture and storage) process. There is a general lack of understanding of the reservoir’s interaction with the CO2 phase at the pore/grain scale. This research addresses the gap in predicting the long-term changes of the CO2–brine–rock interaction using various geochemical reactive transport simulators. Péclet and Damköhler numbers can contribute to a better understanding of geochemical interactions and reactive transport processes. Additionally, the dielectric constant requires further investigation, particularly for pre- and post-CO2–brine–rock interactions. For comprehensive modeling of CO2 storage over various timescales, the geochemical modeling software called the Geochemist’s Workbench was found to outperform others. Wettability alteration is another crucial aspect affecting CO2–brine–rock interactions under varying temperature, pressure, and salinity conditions, which is essential for ensuring long-term CO2 storage security and monitoring. Moreover, dual-energy CT scanning can provide deeper insights into geochemical interactions and their complexities.

A Prediction Model for Soil–Water Characteristic Curve Based on Machine Learning Considering Multiple Factors

Aiming at the problem of long soil–water characteristic curve (SWCC) testing times and the difficulty of prediction accuracy in complex environments, this paper establishes a SWCC prediction model based on a neural network machine learning algorithm which can take into account the influence of multiple factors such as temperature, deformation, and salinity. The input layer of the model can reflect the physical properties of the soil and the influence of the external environment, while the suction is taken as an input variable, which in turn can directly obtain the water content under the corresponding conditions. The predictive ability of the model is verified by comparing and analyzing the predicted results of the SWCC under different temperature, void ratio, and salinity conditions with the experimental results. The research in this paper provides a new method for predicting the SWCC considering multiple factors, and the prediction accuracy of the model is related to the amount of experimental data.

Identification and selection of reference genes for analysis of gene expression by quantitative real-time PCR in the euhalophyte Suaeda altissima (L.) Pall.

ABSTRACT Сoding sequences of seven housekeeping genes: actin SaACT7, ubiquitin-conjugating protein SaUBC10, glyceraldehyde-3-phosphate dehydrogenase SaGAPDH, protein of the large subunit of ribosomes SaL2, α-tubulin SaTUA, translation elongation factor SaeEF1α, and protein phosphatase SaPP2A were identified as candidate reference genes for expression analysis of target genes in the extremely salt tolerant plant Suaeda altissima (L.) Pall. The expression profiles of the genes differed. SaACT7 and SaeEF1α demonstrated the highest expression levels, while the lowest expression levels were found for SaPP2A and SaTUA. SaPP2A and SaeEF1α genes were the most stably expressed at different steady-state salinity levels and different nitrate concentrations in nutrient solutions (NSs). SaL2, SaPP2A, and SaeEF1α genes showed the greatest stability of expression when nitrate was added to nutrient solution of plants grown under conditions of nitrate deficiency. Less constant expression was demonstrated in this experiment by SaACT7 and SaTUA. SaL2, SaACT7, SaeEF1α, and SaUBC10 genes showed the smallest expression changes under salt shock. To validate the use of the most stably expressed genes for normalization of gene expression, we checked them as reference genes to study the expression of the nitrate transporter gene SaNPF6.3 in S. altissima roots under conditions of different salinity and different nitrate supply.

Experimental investigation of zwitterionic surfactant for enhanced oil recovery in unconventional reservoir: A study in the middle bakken formation

Some surfactants may not be effective in harsh reservoir environments because of their tendency to precipitate in high salinity and high temperature conditions. However, Zwitterionic surfactants are considered more tolerant to salinity and temperature. This study investigates the ability of zwitterionic surfactants to improve oil recovery in tight core samples obtained from the Middle Bakken (MB) Formation in North Dakota. The Laboratory tests to determine the efficacy of three betaine zwitterionic surfactants were carried out at a temperature of 90 °C and a high salinity formation brine of 29 wt% to simulate oil recovery under Bakken reservoir conditions. Before the imbibition experiment, the samples underwent petrophysical investigation, and the mineral compositions were determined using the XRD method. The three surfactant samples ME1, CD 2, and CG 3 applied in the study consistently changed the wetting condition of Bakken cores from contact angle of 143.2° to a range of 32°-42°, indicating changing from oil-wet to water-wet. The result obtained shows that the interfacial tension (IFT) between brine and crude oil was reduced from 34.5 mN/m to 8.9 × 10−1 mN/m, 1.19 mN/m, and 2.49 mN/m, respectively, at a critical micelle concentration (CMC) of 0.05 %. The surfactants demonstrated a significantly higher ability to recover oil from the core samples compared to the use of brine only. The imbibition experiments revealed an extra oil recovery of 16.4 % at CMC. Thus, the imbibition of surfactant formulations offers significant potential for enhancing oil recovery in the Bakken Formation.

Dynamics of Noctiluca scintillans blooms: A 20-year study in Jangmok Bay, Korea

This 20-year study (2001–2020) conducted in Jangmok Bay, Korea, assessed the intricate relationships between environmental factors and Noctiluca scintillans blooms. Granger causality tests and PCA analysis were used to assess the impact of sea surface temperature (SST), salinity, dissolved oxygen (DO) concentration, wind patterns, rainfall, and chlorophyll-a (Chl-a) concentration on bloom dynamics. The results revealed significant, albeit delayed, influences of these variables on bloom occurrence, with SST exhibiting a notable 2-month lag and salinity a 1-month lag in their impact. Additionally, the analysis highlighted the significant roles of phosphate, ammonium, and silicate, which influenced N. scintillans blooms with lags of 1 to 3 months. The PCA demonstrates how SST and wind speed during spring and summer, along with wind direction and salinity in winter, significantly impact N. scintillans blooms. We noted not only an increase in large-scale N. scintillans blooms but also a cyclical pattern of occurrence every 3 years. These findings underscore the synergistic effects of environmental factors, highlighting the complex interplay between SST, salinity, DO concentration, and weather conditions to influence bloom patterns. This research enhances our understanding of harmful algal blooms (HABs), emphasizing the importance of a comprehensive approach that considers multiple interconnected environmental variables for predicting and managing N. scintillans blooms.

Salt-tolerant plant growth-promoting bacteria as a versatiletool for combating salt stress in crop plants.

Soil salinization poses a great threat to global agricultural ecosystems, and finding ways to improve the soils affected by salt and maintain soil health and sustainable productivity has become a major challenge. Various physical, chemical and biological approaches are being evaluated to address this escalating environmental issue. Among them, fully utilizing salt-tolerant plant growth-promoting bacteria (PGPB) has been labeled as a potential strategy to alleviate salt stress, since they can not only adapt well to saline soil environments but also enhance soil fertility and plant development under saline conditions. In the last few years, an increasing number of salt-tolerant PGPB have been excavated from specific ecological niches, and various mechanisms mediated by such bacterial strains, including but not limited to siderophore production, nitrogen fixation, enhanced nutrient availability, and phytohormone modulation, have been intensively studied to develop microbial inoculants in agriculture. This review outlines the positive impacts and growth-promoting mechanisms of a variety of salt-tolerant PGPB and opens up new avenues to commercialize cultivable microbes and reduce the detrimental impacts of salt stress on plant growth. Furthermore, considering the practical limitations of salt-tolerant PGPB in the implementation and potential integration of advanced biological techniques in salt-tolerant PGPB to enhance their effectiveness in promoting sustainable agriculture under salt stress are also accentuated.

The use of Pisolithus albus found in saline areas to improve the growth of Eucalyptus seedlings under high salinity conditions

ABSTRACT Salinity is an abiotic factor limiting plant fitness and therefore forest crop productivity, and salt-affected areas have been expanding throughout the world. Ectomycorrhizal (ECM) fungi can improve the salt tolerance of woody plants, including Eucalyptus species To screen for salt-resistant Pisolithus albus (PA) isolates, 16 PA isolates were cultivated on modified Melin-Norkrans agar containing NaCl at concentrations of 0, 10, 20, and 30 dS m−1. The P. albus isolate PA33 had the greatest salt resistance under 10 and 20 dS m−1 NaCl, which are soil salinity levels in salt-affected areas of Thailand. We studied the effect of PA33 on Eucalyptus camaldulensis × E. pellita cuttings under salt stress (0 and 16 dS m−1) for 1 month. PA enhanced the growth of the Eucalyptus seedlings, as indicated by higher relative growth rates in height and root collar diameter of inoculated seedlings compared with non-inoculated seedlings. Moreover, the inoculated seedlings had less cell damage from NaCl, as indicated by significantly lesser leaf thickness and electrolyte leakage than the controls. These findings could lead to practices conferring socioeconomic and environmental benefits, as abandoned salt-affected areas could be reclaimed using such Eucalyptus seedlings inoculated with salt-tolerant ECM fungi.

Examination of role of the AMP-activated protein kinase (Ampk) signaling pathway during low salinity adaptation in the mud crab, Scylla paramamosain, with reference to glucolipid metabolism

It is known that the marine euryhaline crab, mud crab (Scylla paramamosain), is capable of adapting to low salinity conditions through an innate osmoregulatory system. However, the influence of nutritional conditions during low salinity adaptation has not been fully elucidated. In this study, transcriptome analysis was employed to examine whether low salinity affects the AMP-activated protein kinase (Ampk) signaling pathway, and thereby carbohydrate and lipid metabolism. Further analysis revealed that low salinity activated the expression of P-Ampk and promoted glycolysis and lipolysis, which enhances glycogen and lipid utilization. Nutritional deprivation confirmed that nutrients influenced the survival and osmotic pressure regulation of mud crab under to low salinity via the Ampk signaling pathway. During adaptation to low salinity, carbohydrates were the primary energy source in the initial 7 days, followed by lipids. Further investigation showed that pharmacological stimulation of mechanistic targets in the Ampk signaling pathway using metformin could promote the osmotic pressure regulation of mud crab, confirmed the pivotal role of this pathway in low salinity adaptation. Overall, the present study demonstrated that nutrition, metabolism and osmotic pressure regulation interactively contribute to salinity adaptation in mud crab. Specifically, low salinity induced remodeling of nutritional metabolism homeostasis and promoted glycolipid catabolism, thereby providing energy for osmotic pressure regulation in mud crabs.