Increased Water Retention Research Articles

Influence mechanisms of dissolved organic matter and iron minerals on naphthalene attenuation during river infiltration

Natural attenuation of naphthalene (NAP) in riverbank filtration zones is vital for maintaining water quality and is affected by dissolved organic matter (DOM) and iron minerals. However, the effects of DOM and iron minerals on the attenuation of NAP remain unclear. In this study, the attenuation mechanisms of NAP under the influence of DOM and iron minerals were explored in a riverside source area. Field dynamic monitoring data revealed that the NAP concentration in groundwater is mainly influenced by DOM, effective bound‑iron, and the intensity of river water infiltration recharge. Column experiments indicated that DOM with α-Fe2O3 or α-FeO(OH) reduced medium permeability by 8.16 % or 6.85 %, respectively, increasing water retention time. However, they had different effects on the attenuation of NAP. The coexistence of α-Fe2O3 and DOM enhanced NAP attenuation capacity by 9.13 %–45.91 %, while α-FeO(OH) and DOM reduced it by −13.25 % to −24.13 %. These effects were attributed to changes in the medium permeability, particle size, secondary mineral formation, and microbial community structure. Specifically, α-Fe2O3 and DOM reduced medium permeability, increasing the adsorption and biodegradation reaction time of NAP, and promoted secondary mineral (FeCO3) formation, increasing the adsorption capacity of medium for NAP, while α-FeO(OH) and DOM underwent cementation, resulting in larger particles and reduced adsorption capacity for NAP. Additionally, α-FeO(OH) and DOM promoted Shewanlla growth, inhibiting NAP attenuation by competing with NAP-degrading bacteria. These findings improve the understanding of the natural attenuation of polycyclic aromatic hydrocarbons (PAHs) in riverbank filtration, offering a basis for evaluating and controlling PAH pollution risks.

Impact of Inline Polyacrylamide Polymer Flocculation on the Mechanical and Hydrological Properties of Saline Tailings

This study examines the geotechnical and hydro-mechanical behaviour of a model slurry used in high-solids, high-salinity applications, both before and after inline flocculation with an anionic polyacrylamide. Initial evaluations showed untreated tailings (UT) with a water content of 107%, void ratio of 2.6, and dry density of 0.711 t/m3, compared to polymer-amended tailings (PAT) with 53% water content, a void ratio of 1.6, and a dry density of 1.069 t/m3. Post-flocculation consolidometer tests revealed a distinct consolidation mode, with PAT showing 60% less settlement within the first 48 h and achieving 50% more free water drainage. Polymer treatment improved consolidation parameters, yielding a lower compressibility index (Cc of 0.74 vs. 1.05 for raw slurry), a higher coefficient of consolidation (Cv of 0.005 cm2/s for PAT vs. 0.0009 cm2/s for raw slurry), and an increased water retention capacity. Additionally, PAT demonstrated a final void ratio of 0.62 compared to 0.51 for the UT sample and an internal porosity characterised by discrete voids, supporting enhanced stability for long-term rehabilitation. These findings underscore the potential of inline flocculation to improve tailings management in saline conditions.

Correlating Catalyst Growth with Liquid Water Distribution in Polymer Electrolyte Fuel Cells.

This study investigates the impact of liquid water distribution in a polymer electrolyte fuel cell (PEFC) on the spatially heterogeneous platinum (Pt) catalyst degradation. The membrane electrode assemblies (MEAs) are aged using accelerated stress tests (ASTs) in varied cathode gas environments (N2 and air) to instigate Pt catalyst degradation. The study employs high-resolution neutron imaging and synchrotron micro-X-ray diffraction (micro-XRD) to map liquid water distribution and Pt particle size, respectively. Neutron radiographs reveal liquid water accumulation primarily within the diffusion media, especially under flow field lands, due to thermal resistance differences between channels and lands. Aged MEAs exhibit increased water retention, likely due to increased hydrophilicity of the diffusion media with aging. Synchrotron micro-XRD maps unveil significant heterogeneity in Pt particle size distribution in the aged MEAs, correlated with preferential liquid water accumulation under flow field lands. This study highlights the critical role of flow field design and water distribution in catalyst degradation, underscoring the need for innovative strategies to enhance fuel cell durability and performance.

Assessing the Impacts of Nature-Based Solutions on Ecosystem Services: A Water-Energy-Food-Ecosystems Nexus Approach in the Nima River Sub-Basin (Colombia)

Forest ecosystem services are critical for maintaining ecological balance and supporting human well-being from different perspectives. However, rapid land use changes driven by agricultural expansion, urbanization, and industrial activities have significantly altered forest ecosystems, degrading the services they provide. We here conduct an ecosystem service assessment through biophysical and economic estimates for a multipurpose Andean water sub-basin in western Colombia. We compare a business as usual (BAU) with a forest nature-based solution (NbS) scenario focused on forest landscape restoration. The research employed participatory methods for the NbS selection and economic valuation techniques to evaluate water flow regulation, water provisioning, water purification, and food provisioning services. Results show that the NbS scenario yielded a net positive economic impact across most evaluated ecosystem services, with notable trade-offs. Specifically, the NbS scenario increased water retention by 2.9% compared to BAU. Water flow regulation demonstrated the most substantial economic benefit, increasing by EUR 11.39 million/year in the NbS scenario. On the other hand, the food provisioning service presented a reduction of EUR 3.2 million/year in the NbS scenario. These findings highlight the potential of forest-based NbS to address the Water–Energy–Food–Ecosystem (WEFE) nexus challenges. The study’s outcomes provide valuable insights for policymakers and practitioners, supporting the development of Payment for Ecosystem Services schemes and integrating ecosystem service valuation into land use planning and decision-making processes.

Raw feedstock vs. biochar from olive stone: Impact on the sorption–desorption of diclosulam and tropical soil improvement

The addition of carbon-rich materials, such as raw feedstocks (RAW) and biochars, to agricultural soils is on the rise. This activity has many advantages, such as improving fertility, increasing water retention, and sequestering carbon. However, they can also increase the sorption of residual herbicides in the soil, reducing the effectiveness of weed control. Thus, the objective of this study was to evaluate soil improvement and the sorption–desorption process of diclosulam in soil unamended and amended with RAW from olive stone and their biochars produced in two pyrolysis temperatures (300 and 500 °C). Oxisol was used in this study, unamended and amended with RAW and biochars (BC300 and BC500) in a rate of 10% (w w−1). The sorption–desorption process was assessed by batch-equilibrium experiments and the analysis was performed using high-performance liquid chromatography (HPLC). The addition of the three materials to the soil increased the contents of pH, organic carbon, P, K, Ca, Mg, Zn, Fe, Mn, Cu, B, cation exchange capacity, base saturation and decreased H + Al. The unamended soil had Kf (Freundlich sorption coefficient) values of diclosulam sorption and desorption of 1.56 and 12.93 mg(1 − 1/n) L1/n Kg−1, respectively. Unamended soil sorbed 30.60% and desorbed 13.40% of herbicide. Soil amended with RAW, BC300, and BC500 sorbed 31.92, 49.88, and 30.93% of diclosulam and desorbed 13.33, 11.67, and 11.16%, respectively. The addition of RAW and biochars from olive stone has the potential to change the soil fertility, but does not interfere with the bioavailability of diclosulam in weed control under field conditions, since the materials slightly influenced or did not alter the sorption–desorption of diclosulam.

Manure‐biochar blends effectively reduce nutrient leaching and increase water retention in a sandy, agricultural soil: Insights from a field experiment

AbstractOrganic amendments are commonly applied singularly to soils to improve physical, biological and chemical properties, but their combination may be even more advantageous than when applied alone. In this study manure was applied singularly and in combination with biochar (90:10 and 50:50 ratios) to a drought prone agricultural Regosol in a field evaluation. Samples were collected twice a year for 2 years and subjected to testing for moisture retention, nutrient status and microbial activity whilst weed growth was monitored by drone. Substantial seasonal variability in all parameters measured was observed, though all amendments increased actual soil moisture content between 18 and 41% initially; without the addition of biochar (i.e., manure alone) this reverted back to reduced moisture content towards the second year of sampling. None of the tested amendment combinations significantly affected soil‐saturated hydraulic conductivity. Cation exchange capacity decreased as a result of manure addition alone, the addition of 10% biochar and 50% biochar increased this significantly (23%–54% increase). Though microbial biomass and enzyme soil health indicators showed no decisive changes as a result of amendment application, and plant biomass was variable by ground sampling, drone imagery proved that plant heights and health were generally increased as a result of biochar addition to manure, compared with manured soil alone. In summary, despite much field seasonal variability limiting the interpretation of the data, this study nonetheless demonstrates a useful maintenance of improved soil moisture achieved by adding biochar together with manure to a drought‐prone soil agricultural soil.

Combining insitu rainwater harvesting and integrated nutrient management of organic manure improves soil moisture, fertility and crop yields in marginalized areas: A review

Soil moisture stress and infertility are major biophysical constraints which limit crop production and food security in marginalized areas. Marginal areas are mainly associated with low rainfall which is insufficient to support crops until maturity is reached. The use of insitu rainwater harvesting methods such as planting pits, tied ridges, mulching, Zai pits and half-moon can be a solution to reduce moisture stress. This alone cannot improve crop yields hence the need to use integrated nutrient management (INM) of animal manure, biofertilisers, mineral fertiliser and composts to improve soil fertility, structure and increase water retention ability. Combining rainwater harvesting with INM has the potential to mitigate effects of climate change, improve crop yields and meet food demand in marginal areas. Various nutrient sources used as INM can restore soil health, increase microbial population, nutrient mineralisation and improve soil quality. Use of biofertilisers in agriculture reduces soil toxicity, improve nutrient availability and create a conducive environment for crop growth and development. Integration of tied ridges with cattle manure and mineral fertiliser has the potential of increasing infiltration rates, reducing surface runoff and increase crop yields with 50-150% regardless of soil type. This chapter sought to come up review the effects of rainwater harvesting methods and INM on soil fertility, moisture stress and crop yields in marginalized areas.

Evaluating the effects of insoluble date fruit (Phoenix dactylifera L.) fibers on meat analogue patties composed of pea and wheat protein isolates

This study aimed to evaluate the effects of date pomace fibers (DF) on the physicochemical properties of plant-based ground patty analogues. Previously optimized pea and wheat protein isolates were incorporated with varying concentrations of DF, i.e., 0 %, 2.5 %, 5 %, 7.5 %, and 10 % w/w. The addition of DF increased water retention in the patties, leading to subsequent changes in the patty structure. Frequency sweep results confirmed that the presence of DF contributed to structural stability, where patties exhibited more solid-like characteristics and stronger internal bonds, which also increased hardness from ∼65 g to 160–175 g. This could positively correlate with the brittleness of the patties, where large deformation results showed that high DF formulations were more brittle, which reduced springiness, as evident in DF7.5 (from ∼2 mm in DF0 to 1.89 mm in DF7.5). The microstructure revealed that high DF content increased patty fibrousness and led to a uniform structure. Therefore, high DF concentrations seemed to positively impact the analogue structure. DF also contributed to patty analogue color by imparting brown–red tones which may result in a closer appearance to conventional beef patties. This study establishes a foundation for further studies to be conducted on determining the optimum DF concentration that yields patty analogues with desirable structure as well as appearance.

Separation layers and their influence on green roof water storage

ABSTRACT This study deals with how adding separation layers to flat roofs improves their design, construction, and sustainability. Better understanding and use of these layers leads to increased durability, lower maintenance, and simpler execution, with potential for material reuse and performance enhancement. Currently, the optional nature of separation layers hinders the overall sustainability of roofing systems, so this research seeks to guide building professionals in selecting suitable separation layers for flat roofs, considering factors like location, function, material composition, and mass. Particularly, it examines the impact of Water Storage layers on self-sustaining green roofs, aiming to enhance thermal performance, especially when water is scarce. Results indicate that installing these layers significantly increases water retention below the drainage layer, primarily in extensive green roofs, where values rise by 17%. Water Storage layers also extend water availability after rainfall, raising maximum daily humidity levels inside the roof by up to 10% on the third day post-rainfall compared to green roofs without such a layer. Highlights The optional character related to separation layers lends a voluntary aspect to sustainability. Proper selection of separation layers’ characteristics ensures optimal roof functionality. The Water Storage separation layer increases humidity on the green roof's inner layers. The Water Storage separation layer extends the time for water usage on green roofs.

Biochar Production from Plant Residues: A Sustainable Approach for Carbon Sequestration and Soil Fertility Improvement

This review article explores the sustainable practice of producing biochar from plant residues, effectively transforming green waste into a valuable resource commonly referred to as “green gold”. It discussed mainly on the pyrolysis process of biochar production, and the impact of different pyrolysis methods on the resulting biochar's properties, including surface area, porosity, and nutrient holding capacity. Further, the review analyzes the multifaceted benefits of biochar for soil health and plant growth. It highlights how biochar can improve soil structure, increase water retention, and enhance nutrient availability, leading to healthier and more productive agricultural lands. Additionally, the review explores biochar's potential in influencing the soil microbial community, potentially promoting beneficial organisms and suppressing harmful pathogens. It also explores biochar's role in mitigating climate change by capturing and storing atmospheric carbon, effectively reducing greenhouse gas emissions. However, a balanced perspective is maintained by acknowledging potential drawbacks associated with biochar use, such as the need for further research to optimize production methods and potential negative impacts on certain soil fauna. This review highlights biochar's promise as a sustainable, cost-effective solution for agriculture and environmental issues. Biochar adoption can lead to a greener future through carbon capture, soil health, and waste management.

Unraveling the role of anthropogenic and hydrologic drivers with respect to the optical and molecular properties of dissolved organic matter and organic phosphorus in a P-contaminated river

Anthropogenic and hydrological drivers are key factors influencing the fate of dissolved organic matter (DOM) and dissolved organic phosphorus (DOP) in river runoff. However, how anthropogenic disturbances and hydrological conditions jointly affect the composition and characteristics of DOM and DOP in river runoff remains unclear. This study used fluorescence spectroscopy, Fourier transform ion cyclotron resonance mass spectrometry, and the stable water isotopes to interpret the chemical composition and properties of DOM and DOP as well as their linkages to anthropogenic disturbances and hydrological conditions in a typical P-contaminated tributary to the central Yangtze River. The results show in the wet season, the average abundance of humic-like components in DOM exceeded 60 %, while the average abundance of tryptophan-like components in DOM exceeded 50 % in the dry season. During the dry season, hydrological conditions had a greater impact on highly unsaturated DOM compounds compared to anthropogenic disturbances because a decrease in precipitation reduced the transport of terrestrial DOM into aquatic systems and increased water retention time in the river, promoting the production of unsaturated compounds from photochemistry. The effects of the two factors were similar in the wet season because active agricultural activities and intense precipitation jointly facilitated the entry of exogenous humics into the runoff, leading to the similar relative abundance of highly unsaturated DOM compounds associated with both factors. Anthropogenic disturbances had a greater impact on aliphatic DOM and DOP than hydrological conditions, which was associated with intense human activities in the watershed, such as phosphate mining, agricultural cultivation, and domestic sewage discharge. This study provides new knowledge about the composition, properties and underlying mechanisms of DOM and DOP in the P-contaminated watershed runoff.

On the role of water balance as a prerequisite for aquatic and wetland ecosystems management: A case study of the Biebrza catchment, Poland

Water balance quantifies the inflows and outflows in a river basin, crucial for assessing the water resources of a given area. Quantified water balance should therefore be the key step in environmental quality assessment. However, due to the lack of data on reasonable spatiotemporal scales and quality, water balance studies are scarce. The aim of the paper was to provide a water balance analysis as a prerequisite for aquatic and wetland ecosystems management in the Biebrza Valley, Poland. A Penck-Oppokov method was used to assess the annual water balance, and runoff coefficient for 1951–2021. Data were extracted for the daily simulated dataset of Poland. The average annual water balance of the Biebrza basin encompassed of 561 mm of precipitation, 485 mm of evapotranspiration, 101 mm of runoff, and −25 mm of water retention. Analysis of 17 sub-basins indicated a declining tendency in water resources over the study period. The average runoff coefficient in the Biebrza basins is equal to 0.17. Findings presented here indicate that the significant deficit in the water balance in the region is highly unlikely to be compensated by the course of natural hydrological processes. This reveals the need for quick actions oriented at improvement of water balance by reducing the runoff and evapotranspiration. The study provides convincing evidence that if the observed tendencies of water balance elements are continued, the reinstallation of spatially distributed, abundant measures of increasing water retention may be the only way to assure the appropriate ecological status of aquatic and wetland ecosystems.

A Field Study to Assess the Impacts of Biochar Amendment on Runoff Quality from Newly Established Green Roofs

Green roofs (GRs) are a widely recognized green infrastructure (GI) strategy that helps reduce runoff volume and runoff pollution caused by the significant increase in impervious urban areas. However, the leaching of several nutrients from GR substrates is a growing concern. Biochar, a carbon-rich material, possesses advantageous properties that can help address such environmental challenges associated with GRs. Therefore, this paper aimed to undertake a field study to investigate the impacts of various biochar application methods, particle sizes, and amendment rates on the quality of runoff from GRs. Observational data of runoff quality were collected over a two-month period from five newly established 1 m × 1 m biochar-amended GR test beds and a control test bed without biochar, with all test beds subjected to artificially simulated rainfall. The results indicated that the addition of biochar did not result in a significant improvement in runoff pH, whereas the electrical conductivity (EC) was higher in runoff from GRs with biochar-amended substrates. When comparing the total nitrogen (TN) concentration in runoff from the non-biochar GR (ranging from 3.7 to 31 mg/L), all biochar test beds exhibited higher TN release (4.8 to 58 mg/L), except for the bed where medium biochar particles were applied at the bottom of the substrate (ranging from 2.2 to 21 mg/L). Additionally, all biochar-amended GRs exhibited higher TP concentrations in runoff (0.81 to 2.41 mg/L) when compared to the control GR (0.35 to 0.67 mg/L). Among the different biochar setups, GR with fine biochar particles applied to the surface of the substrate had the poorest performance in improving runoff water quality. Despite these mixed results, biochar holds significant potential to improve runoff quality by significantly increasing water retention, thereby reducing pollutant loads.

Effect of Zero Tillage on Soil Properties, Weed Dynamics and Performance of Chickpea under Rice –Chickpea Cropping System: A Review

In many nations across the world, farming is an important industry. Sustainable farming methods known as zero tillage systems entail planting seeds without tillage, which disturbs the soil. With this approach, crop residues from the previous year are left on the earth's surface and new plants are planted straight into the undisturbed soil, as opposed to plowing. This method aids in preserving the structure of the soil, decreasing soil erosion, retaining more water, and enhancing soil health. Farmers can benefit from enhanced soil health, decreased soil erosion, higher crop yields, and environmental sustainability by implementing sustainable farming practices. By limiting soil disturbance and shielding soil particles from the elements, this system aids in the reduction of soil erosion. Additionally contributes to improved soil structure, which raises soil fertility, and helps hold onto soil moisture, which lessens the need for irrigation. The amount of tillage and fuel used in zero-tillage systems can be less than in conventional tillage methods. In comparison to traditional tillage methods, systems require less fuel and tillage, which can save farmers money and lessen their carbon footprint. This is true because these systems raise soil organic matter levels, which in turn raise soil nutrient availability and improve soil fertility. Moreover, zero tillage systems can increase water retention in the soil, which can enhances crop growth and yield by improving soil structure and moisture retention, while also reducing weed competition. By reducing soil erosion, conserving soil moisture, and improving soil health, these systems help to promote environmental sustainability. Also reduce greenhouse gas emissions by reducing fuel usage and sequester carbon in the soil through the accumulation of crop residues. Therefore, farmers should adopt zero-tillage systems to enhance their productivity, reduce costs, and promote environmental sustainability.

Effect of konjac glucomannan on heat-induced pea protein isolate hydrogels: Evaluation of structure and formation mechanisms

The roles of increasing concentration of konjac glucomannan polysaccharide (KGM) in modifying the thermal, textural, and rheological properties of heat-induced pea protein isolate (PPI) hydrogels at neutral pH and low ionic strength were investigated in this study. Differential scanning calorimetry was first applied to investigate the effect of KGM addition on the thermal properties of pea proteins, finding that an addition of 0.5 % w/v increased the glass transition temperature of pea proteins (from 150 to 154 °C) while on the contrary, higher concentrations of 1.0–1.5 % w/v reduced glass transition temperatures (from 150 °C to ∼ 144 °C). Water holding capacity highlighted that KGM addition significantly increased water retention, reaching values up to 90 % for KGM concentration ≥ 1.0 % w/v. Confocal laser scanning microscopy showed the presence of a phase separation system with increasing concentrations of KGM. Molecular interactions and Fourier transform infrared spectroscopy analysis highlighted that the hydrogels were mainly stabilized by non-covalent intermolecular interactions. Texture analysis confirmed that KGM significantly influenced texture of the hydrogels, in which 1.5 % w/v KGM presented the highest hardness value of 1.34 N. Lastly, small amplitude rotational and oscillatory rheology was employed to evaluate the hydrogels viscosity and viscoelastic properties, which both were significantly increased with increasing KGM concentrations.

Analysis of the potential for increasing water retention in road pavements on public roads in cities: a case study based on the Old Town of Płock

Współczesny rozwój miast wymaga zastosowania nowoczesnych systemów, szczególnie w zakresie odprowadzania wód opadowych i roztopowych z powierzchni pasów drogowych. W związku z dużą ilością nawierzchni utwardzonych na obszarach zurbanizowanych niezbędne jest szukanie rozwiązań pozwalających na zatrzymanie wody w miejscu jej opadu. Bardzo ważnym zagadnieniem są tu powierzchnie biologicznie czynne. Projektując konkretne rozwiązania, w pierwszej kolejności należy dokonać przeglądu obowiązujących przepisów wodnych i drogowych. Na ich podstawie przeprowadzono analizę możliwości zwiększenia retencji wody w pasach buforowych drogi dla pieszych na obszarze Starego Miasta w Płocku.

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and a popular target for enhancing the productivity of farmed fish. We previously developed an mstn-knockout breed of the aquaculture fish red sea bream (Pagrus major) using genome editing technology. However, little is known about the effects of mstn disruption on the fillet quality of red sea bream and other fish species. In this study, we used fillets of mstn-deficient red sea bream to evaluate their compositional and textural changes during refrigeration. Compared to the wild type, the mutant fillets exhibited an increase in moisture content and a decrease in drippings, indicating an enhanced water-holding capacity. Furthermore, the mutant fillets showed increased water retention and marginally lower collagen content, resulting in lower breaking force, an index of texture. In conclusion, we demonstrated that mstn disruption alters the compositional and textural properties of red sea bream fillets.

Unveiling the Potential Scope of Nanoparticles in the Current Era of Crop Productivity

Nanotechnology, a revolutionary field encompassing the manipulation of matter on an atomic or molecular scale, holds immense potential for upgrading wide areas, including agriculture. Understanding the scope of nanotechnology, researchers have directed their focus towards addressing the challenges in agriculture and enhancing crop productivity. Nanoparticles offer unique properties, including high surface area and reactivity, that can be harnessed to optimize nutrient delivery, mitigate soil toxicity, and enhance plant growth. Various studies have demonstrated the effectiveness of nanoparticles in increasing crop yields, improving nutrient uptake efficiency, and reducing environmental impacts associated with conventional agricultural practices with sustainable agriculture. Nanotechnology overcomes various challenges encountered in traditional agricultural practices including limited availability of nutrients in the soil, inefficient nutrient uptake by plants, soil degradation, and environmental pollution by providing targeted nutrient delivery, improving nutrient absorption, and mitigating environmental impacts. Also, nanoparticle interactions with plants and microbes and strengthening symbiotic relationships by providing active nutrient supplies to microbes. Furthermore, nanoparticles can improve soil structure and fertility by reducing compaction, increasing water retention, and enhancing soil aggregation. These improvements in soil quality not only benefit crop growth but also contribute to sustainable land management practices.This review paper provides an overview of the current research landscape in the application of nanoparticles in agriculture, highlighting key findings, challenges, and future prospects. By leveraging the principles of nanotechnology, agricultural scientists and practitioners aim to revolutionize crop production, meet the needs of farmers, and ensure food security in the face of evolving environmental and socio-economic challenges.

An Overview of the Effects of Tenapanor on Visceral Hypersensitivity in the Treatment of Irritable Bowel Syndrome with Constipation.

Patients with irritable bowel syndrome with constipation (IBS-C) experience persistent abdominal pain, a common symptom leading to greater healthcare utilization and reports of treatment non-response. Clinically significant improvements in abdominal pain were observed in clinical trials of tenapanor, a first-in-class inhibitor of sodium/hydrogen exchanger isoform 3 (NHE3), for the treatment of IBS-C in adults. This narrative review reports the current knowledge about visceral hypersensitivity as a mechanism for abdominal pain in patients with IBS-C and explores the published evidence for hypothesized mechanisms by which tenapanor may reduce visceral hypersensitivity leading to the observed clinical response of decreased abdominal pain. Abdominal pain is experienced through activation and signaling of nociceptive dorsal root ganglia that innervate the gut. These sensory afferent neurons may become hypersensitized through signaling of transient receptor potential cation channel subfamily V member 1 (TRPV1), resulting in reduced action potential thresholds. TRPV1 signaling is also a key component of the proinflammatory cascade involving mast cell responses to macromolecule exposure following permeation through the intestinal epithelium. Indirect evidence of this pathway is supported by observations of higher pain in association with increased intestinal permeability in patients with IBS. Tenapanor reduces intestinal sodium absorption, leading to increased water retention in the intestinal lumen, thereby improving gastrointestinal motility. In animal models of visceral hypersensitivity, tenapanor normalized visceromotor responses and normalized TRPV1-mediated nociceptive signaling. By improving gastrointestinal motility, decreasing intestinal permeability and inflammation, and normalizing nociception through decreased TRPV1 signaling, tenapanor may reduce visceral hypersensitivity, leading to less abdominal pain in patients with IBS-C. Therapies that have demonstrated effects on visceral hypersensitivity may be the future direction for meaningful abdominal pain relief for patients with IBS-C.

Drought accentuates the role of mycorrhiza in phosphorus uptake, part II – The intraradical enzymatic response

Edaphic drought reduces phosphorus (P) diffusivity in soils and arbuscular mycorrhizal fungi (AMF) can compensate for this. We recently showed, along a high-resolution substrate moisture gradient, that AMF effectively deliver P to plants under drought from areas beyond the reach of roots. Here, we investigated how edaphic drought affected the active sites of P exchange between AMF and plants inside the roots using different histochemical stains.Inoculation of dwarf tomato plants (cv. MicroTom) with AMF (Rhizophagus irregularis) slightly increased water retention (decreased the water potential) in substrates, decreased root length, and increased shoot P concentrations compared to non-mycorrhizal plants. Despite their reduced root length, mycorrhizal tomato plants showed a surprisingly congruent physiological drought stress response with their non-mycorrhizal counterparts. However, the activity of alkaline phosphatase (ALP) detected in intraradical fungal structures decreased significantly as soil and xylem water potentials decreased. The decline of ALP activity with increasing drought intensity was accompanied by a reduction of elevated P concentration benefits in shoots of mycorrhizal plants compared to non-mycorrhizal plants.Therefore, we conclude that edaphic drought can restrict the nutritional advantages that plants receive from AMF at the root-fungal interface. This is one of the direct consequences of drought.