Search Results (593)

Plant nitrate transporters in the NPF (NRT1) family are characterized by multifunctionality and their involvement in a number of physiological processes. The proteins in this family have been identified in many monocotyledonous and dicotyledonous species: a bioinformatic analysis predicts from 20 to 139 members in the plant genomes sequenced so far, including mosses. Plant NPFs are phylogenetically related to proton-coupled oligopeptide transporters, which are evolutionally conserved in all kingdoms of life apart from Archaea. The phylogenetic analysis of the plant NPF family is based on the amino acid sequences present in databases; an analysis identified a separate NPF6 clade (subfamily) with the first plant nitrate transporters studied at the molecular level. The available information proves that proteins of the NPF6 clade play key roles not only in the supply of nitrate and its allocation within different parts of plants but also in the transport of chloride, amino acids, ammonium, and plant hormones such as auxins and ABA. Moreover, members of the NPF6 family participate in the perception of nitrate and ammonium, signaling, plant responses to different abiotic stresses, and the development of tolerance to these stresses and contribute to the structure of the root–soil microbiome composition. The available information allows us to conclude that NPF6 genes are among the promising targets for engineering/editing to increase the productivity of crops and their tolerance to stresses. The present review summarizes the available published data and our own results on members of the NPF6 clade of nitrate transporters, especially under salinity; we outline their molecular, structural, and functional characteristics and suggest potential lines for future research. Full article

Three different types of common halophytes (Haloxylon ammodendron, Tamarix chinensis, and Phragmites australis) in northwest China were used in this study. A field experiment approach was adopted, involving five solutions with different salt concentrations (0, 150, 200, 250, and 300 mmol·L⁻¹) for salt stress treatment. The changes in photosynthetic characteristics and physiological characteristics of three different types of halophytes and their relationship with biomass were measured and analyzed. The results showed that (1) with the increase in salt concentration, the plant height, stem diameter, and biomass of three halophytes showed a downward trend. (2) The chlorophyll a, chlorophyll b, and total chlorophyll contents of Haloxylon ammodendron and Tamarix chinensis first increased and then decreased with the increase in salt concentration. Phragmites australis showed a decreasing trend. The malondialdehyde content of three halophytes showed a clear increasing trend. (3) Under different salt concentrations, the diurnal changes in the net photosynthetic rate, transpiration rate, stomatal conductance, and water use efficiency of three different types of halophytes all showed an “M” trend. The diurnal variation in intercellular carbon dioxide concentration showed a “W” trend. (4) With the increase in salt concentration, the daily average values of the net photosynthetic rate, transpiration rate, and stomatal conductance of three different types of halophytes showed a downward trend. The daily average value of intercellular carbon dioxide concentration showed a “V”-shaped trend of first decreasing and then increasing. The daily average value of water use efficiency showed a “single peak” trend of first increasing and then decreasing. Haloxylon ammodendron and Phragmites australis were mainly limited by stomata at a salt concentration of 0~200 mmol·L⁻¹ and were mainly limited by non-stomata at a salt concentration of 250~300 mmol·L⁻¹. Tamarix chinensis is mainly limited by stomata at a salt concentration of 0~250 mmol·L⁻¹ and is mainly limited by non-stomata at a salt concentration of 300 mmol·L⁻¹. Compared with Haloxylon ammodendron and Phragmites australis, Tamarix chinensis has better water use efficiency, salt tolerance, and adaptability. (5) Meteorological factors, growth morphological factors, physiological factors, photosynthetic factors, and salt concentration have higher explanatory degrees, which have significant effects on the biomass of halophytes. Among them, salt concentration and growth morphological factors have direct core driving effects on the biomass of three different types of halophytes, while meteorological factors, photosynthetic factors, and physiological factors have different effects due to the differences in and complexity of halophytes. This study can provide a theoretical basis for further revealing the adaptation mechanism of different halophytes to salt stress. Full article

Soil salinization is an important stress factor that limits plant growth and yield. Increased salinization is projected to affect more than 50% of all arable land by 2050. In addition, the growing demand for food, together with the increase in the world population, forces the need to seek salt-tolerant crops. Quinoa (Chenopodium quinoa Willd.) is an Andean crop of high importance, due to its nutritional characteristics and high tolerance to different abiotic stresses. The aim of this work is to determine the physiological, anatomical, and biochemical salt-tolerance mechanisms of a salt-tolerant (Vikinga) and a salt-sensitive (Regalona) quinoa variety. Plants were subjected to salinity stress for 15 days, starting at 100 mM NaCl until progressively reaching 400 mM NaCl. Physiological, anatomical, and biochemical parameters including growth, chlorophyll content, quantum yield of PSII (ϕ_PSII), gas exchange, stomatal density, size, and lipid peroxidation (via malondialdehyde, MDA) were measured. Results show that chlorophyll content, ϕ_PSII, and MDA were not significantly reduced under saline stress in both varieties. The most stress-affected process was the CO₂ net assimilation, with an up to 60% reduction in both varieties, yet Vikinga produced higher dry weight than Regalona due to the number of leaves. The stomatal densities increased under salinity for both varieties, with Regalona the one showing higher values. The averaged stomatal size was also reduced under salinity in both varieties. The capacity of Vikinga to generate higher dry weight is a function of the capacity to generate greater amounts of leaves and roots in any condition. The stomatal control is a key mechanism in quinoa’s salinity tolerance, acquiring higher densities with smaller sizes for efficient management of water loss and carbon assimilation. These findings highlight the potential of Vikinga for cultivation in temperate salinized environments during winter, such as Deltas and lowlands where rice is grown during summer. Full article

Acrostichum aureum is a halophytic pantropical invasive fern growing in mangroves and swamps. Its association with arbuscular mycorrhizal fungi (AMF) has been reported in Asia. AMF and their symbiosis (AM) commonly colonise the absorption organs of terrestrial plants worldwide. Furthermore, AMF/AM are well known for their capacity to bioaccumulate toxic elements and to alleviate biotic and abiotic stress (e.g., salinity stress) in their hosts. However, the mechanisms underlying AMF involvement in the halophytism of A. aureum and the structures where NaCl accumulates remain unknown. This study shows that A. aureum forms AM in margins of natural thermal ponds in Neotropical wetlands. All mature sporophytes were colonised by AMF, with high percentages for root length (ca. 57%), arbuscules (23), and hyphae (25) and low values for vesicles (2%). In A. aureum–AMF symbiosis, NaCl accumulated in AMF vesicles, and CaSO₄ precipitated in colonised roots. Therefore, AM can contribute to the halophytic nature of this fern, allowing it to thrive in saline and thermal environments by capturing NaCl from fern tissues, compartmentalising it inside its vesicles, and precipitating CaSO₄. Full article

Fresh-water food production/agriculture for both plants and animals utilizes some 70% of the planets’ fresh water, produces some 26% of greenhouse gas emissions and has a longish list of other societal-related issues. Given the developing and extant shortages of arable land, fresh water and food, along with climate/ecosystem issues, there is a need to greatly reduce these adverse effects of fresh-water agriculture. There are, especially since the advent of the 4th Agricultural Revolution, a number of major frontier technologies and functionality changes along with prospective alternatives which could, when combined and collectivized in various ways, massively improve the practices, adverse impacts and outlook of food production. These include cellular/factory agriculture; photosynthesis alternatives; a shift to off-grids and roads/back-to-the-future, do-it-yourself living (aka de-urbanization); cultivation of halophytes on wastelands using saline water; insects; frontier energetics; health-related market changes; and vertical farms/hydroponics/aeroponics. Shifting to these and other prospective alternatives would utilize far less arable land and fresh water, produce far less greenhouse gases and reduce food costs and pollution while increasing food production. Full article

Land degradation due to salinity and prolonged drought poses significant global challenges by reducing crop yields, depleting resources, and disrupting ecosystems. Halophytes, equipped with adaptive traits for drought and soil salinity, and their associations with halotolerant microbes, offer promising solutions for restoring degraded areas sustainably. This study evaluated the effects of halophilic sulfur-oxidizing bacteria (SOB), specifically Halothiobacillus halophilus, on the physiological and biochemical responses of the halophyte Plantago coronopus L. under drought and salt stress. We analyzed the accumulation of ions (Na, Cl, K) and sulfur (S), along with growth parameters, glutathione levels, photosynthetic pigments, proline, and phenolic compounds. Drought significantly reduced water content (nearly 10-fold in plants without SOB and 4-fold in those with SOB). The leaf growth tolerance index improved by 70% in control plants and 30% in moderately salt-stressed plants (300 mM NaCl) after SOB application. SOB increased sulfur content in all treatments except at high salinity (600 mM NaCl), reduced toxic sodium and chloride ion accumulation, and enhanced potassium levels under drought and moderate salinity. Proline, total phenolic, and malondialdehyde (MDA) levels were highest in drought-stressed plants, regardless of SOB inoculation. SOB inoculation increased GSH levels in both control and 300 mM NaCl-treated plants, while GSSG levels remained constant. These findings highlight the potential of SOB as beneficial microorganisms to enhance sulfur availability and improve P. coronopus tolerance to moderate salt stress. Full article

Background: Mangroves are one of the key nature-based solutions that mitigate climate change impacts. Even though they are halophytic in nature, seedlings are vulnerable to high salinity for their establishment. This study investigated the effects of different salinities on seedling growth and mineral element composition of two dominant species (Avicennia marina and Rhizophora mucronata). Methods: The study followed a randomized complete block design, i.e., main treatments (growing environment in greenhouse (GH) or net house (NH)) and four sub-treatments under 21 replicates, i.e., irrigation with 100% freshwater (0.4%o—T1), 100% saline water (35%o—T2), 50% saline water and 50% freshwater (18%o—T3), and brine water (60%o—T4). Results: Results revealed that A. marina seeds can optimally germinate and survive well reaching 80% in NH under T1. However, T2 and T4 seedlings had the lowest survival. Mineral element analysis showed that A. marina grown under NH recorded higher levels of Ca, Mg, and K which increased with increasing levels of salinity. The opposite was true with Na levels. R. mucronata on the other hand, recorded completely opposite findings with T1 seedlings reaching 95% in the greenhouse while T3 reached almost 60%. Conclusions: It can be concluded that mangrove species can optimally germinate and grow in both freshwater and 50% saline water, but growth reduction occurs with seawater and complete growth inhibition with brine water. Full article

This study examined the phytochemical profile and biomedical activities of Nitraria retusa, a halophytic and drought-resistant shrub. HPLC analysis showed gallic acid (1905.1 μg/g), catechin (1984.1 μg/g), and ellagic acid (2671.1 μg/g) as the primary constituents, while FT-IR analysis revealed a complex organic profile with significant functional groups. The extract demonstrated strong antioxidant activity in DPPH assays, outperforming ascorbic acid (IC₅₀ = 18.7 ± 1.0 μg/mL) with an IC₅₀ of 16.4 ± 4.4 μg/mL. It demonstrated specific antiproliferative effects on cancer cell lines as it showed selective cytotoxicity against cancer cell lines; normal WI38 cells were largely unaffected, showing 50.0% viability at 125 μg/mL. The most sensitive cell line was Caco2, which showed 50.0% viability at 125 μg/mL. Anti-diabetic properties were exhibited by means of inhibition of α-amylase (IC₅₀ = 68.2 ± 4.2 μg/mL) and α-glucosidase (IC₅₀ = 22.8 ± 3.3 μg/mL). Additionally, antimicrobial activity was observed to be broad-spectrum, and it was most effective against E. coli (32.6 mm inhibition zone at 400 μg/mL) and Penicillium glabrum (35.3 mm at 400 μg/mL). These findings highlight the potential of N. retusa in developing plant-based therapeutic approaches. Full article

Salinity stress influences plants throughout their entire life cycle. However, little is known about the response of plants to long-term salinity stress (LSS). In this study, Puccinellia tenuiflora, a perennial halophyte grass, was exposed to 300 mM NaCl for two years (completely randomized experiment design with three biological replicates). We measured the photosynthetic parameters and plant hormones and employed a widely targeted metabolomics approach to quantify metabolites. Our results revealed that LSS induced significant metabolic changes in P. tenuiflora, inhibiting the accumulation of 11 organic acids in the leaves and 24 organic acids in the roots and enhancing the accumulation of 15 flavonoids in the leaves and 11 phenolamides in the roots. The elevated accumulation of the flavonoids and phenolamides increased the ability of P. tenuiflora to scavenge reactive oxygen species. A comparative analysis with short-term salinity stress revealed that the specific responses to long-term salinity stress (LSS) included enhanced flavonoid accumulation and reduced amino acid accumulation, which contributed to the adaptation of P. tenuiflora to LSS. LSS upregulated the levels of abscisic acid in the leaves and ACC (a direct precursor of ethylene) in the roots, while it downregulated the levels of cytokinins and jasmonic acids in both the organs. These tolerance-associated changes in plant hormones would be expected to reprogram the energy allocation among growth, pathogen defense, and salinity stress response. We propose that abscisic acid, ethylene, cytokinins, and jasmonic acids may interact with each other to construct a salinity stress response network during the adaptation of P. tenuiflora to LSS, which mediates salinity stress response and significant metabolic changes. Our results provided novel insights into the plant hormone-regulated metabolic response of the plants under LSS, which can enhance our understanding of plant salinity tolerance. Full article

Mesembryanthemum crystallinum L., commonly known as the ice plant, is a halophyte recognized for its exceptional salinity tolerance. This study aimed to determine the optimal NaCl concentration for promoting plant growth, D-pinitol, and other phytochemicals in M. crystallinum cultivated in a hydroponics system. Seedlings of M. crystallinum were transplanted into a hydroponic system and subjected to different NaCl concentrations (0, 100, 200, 300, 400, and 500 mM) in the nutrient solution. To evaluate the plant’s response to salinity stress, measurements were conducted on growth parameters, chlorophyll and carotenoid levels, total flavonoid and polyphenol contents, and DPPH scavenging activity. The optimal NaCl concentration for growth was found to be 200 mM, at which the shoot fresh and dry weights were highest. Additionally, total chlorophyll and carotenoid contents were maximized at 200 mM NaCl, with a subsequent decrease at higher concentrations. The highest DPPH scavenging activity was observed in the 200 mM NaCl treatment, which correlated with increased levels of total flavonoids and polyphenols. These results indicated that optimizing NaCl concentration can enhance the antioxidant activity of Mesembryanthemum crystallinum L. The D-pinitol content also peaked at 200 mM NaCl treatment, further supporting its role osmotic adjustment under salinity stress. M. crystallinum exhibited enhanced antioxidant production and cellular protective functions at 200 mM NaCl, which optimized its biochemical defense mechanisms and helped maintain physiological functions under salinity stress. These findings provide valuable insights for agricultural and biological applications, particularly in cultivating M. crystallinum for its bioactive compounds. Full article

Soil salinization is a serious threat to the ecological environment and sustainable agricultural development in the arid regions of northwest China. Optimal soil salinization amelioration methods were eagerly explored under different soil salinity levels. Sesbania and hairy vetch are salt-tolerant plants, and green manure improved the saline environment. In this study, two leguminous halophytic crops, sesbania (Sesbania cannabina) and hairy vetch (Vicia villosa), were planted under different salinity levels, combined with three saline soil improvement measures, namely gravel mulching, manure application, and straw returning. No improvement measures and no salinity treatment was set as the control (CK). This study was conducted to analyze the effects of soil salinization improvement measures on the growth and ion uptake of sesbania and hairy vetch as biological measures under different soil salinity levels. Sesbania under manure application absorbed the highest soil Na⁺ (2.71 g kg⁻¹) and Cl⁻ (2.66 g kg⁻¹) amounts at a soil salinity of 3.2 g kg⁻¹, which was 14.7% and 10.95% higher than under gravel mulching and straw returning, respectively. Na⁺ and Cl⁻ absorption of hairy vetch under manure application reached the highest value of 1.39 g kg⁻¹ and 1.38 g kg⁻¹ at a soil salinity of 1.6 g kg⁻¹, which was 24.46% and 22.31% higher than under gravel mulching and straw returning, respectively. Plant height and stem diameter as well as root growth and development of sesbania and hairy vetch were limited at soil salinities greater than 1.6 g kg⁻¹ and 0.8 g kg⁻¹. Overall, sesbania and hairy vetch effectively absorbed both soil Na⁺ and Cl⁻ under manure application, thus regulating soil salinity and reducing soil salinization. However, soil salinity levels greater than 3.2 g kg⁻¹ and 1.6 g kg⁻¹ not only weakened the ionic absorption capacity but also inhibited the growth and development of sesbania and hairy vetch. This study provides evidence that soil salt ion absorption by sesbania and hairy vetch is promoted effectively, ameliorating soil salinity, under manure application as compared to under gravel mulching and straw returning. Full article

Entosthodon hungaricus is a rare moss species of the salty grasslands in Serbia. It is threatened with extinction due to habitat destruction and loss, although it reproduces sexually. In this study, we tested different models predicting its distribution under several climate scenarios over the next 8 decades. All models tested indicated a reduction in range to varying extents. Due to the specific substrate type as well as the predicted loss owing to the climate change, shifting is not an option for the survival of this species; and, therefore, it deserves special attention for its conservation and management. Full article

Zygophyllum propinquum (Decne.) is a leaf succulent C₄ perennial found in arid saline areas of southern Pakistan and neighboring countries, where it is utilized as herbal medicine. This study investigated how growth, water relations, ion content, chlorophyll fluorescence, and antioxidant system of Z. propinquum change as salinity levels increase (0, 150, 300, 600, and 900 mM NaCl). Salinity increments inhibited total plant fresh weight, whereas dry weight remained constant at moderate salinity and decreased at high salinity. Leaf area, succulence, and relative water content decreased as salinity increased. Similarly, the sap osmotic potential of both roots and shoots declined as NaCl concentrations increased. Except for a transitory increase in roots at 300 mM NaCl, sodium concentrations in roots and shoots increased constitutively to more than five times higher under saline conditions than in non-saline controls. Root potassium increased briefly at 300 mM NaCl but did not respond to NaCl treatments in the leaf. Photosynthetic pigments increased with 300 and 600 mM NaCl compared to non-saline treatments, although carotenoids appeared unaffected by NaCl treatments. Except for very high NaCl concentration (900 mM), salinity showed no significant effect on the maximum efficiency of photosystem II photochemistry (Fv/Fm). Light response curves demonstrated reduced absolute (ETR^*) and maximum electron transport rates (ETR_max) for the 600 and 900 mM NaCl treatments. The alpha (α), which indicates the maximum yield of photosynthesis, decreased with increasing NaCl concentrations, reaching its lowest at 900 mM NaCl. Non-photochemical quenching (NPQ) values were significantly higher under 150 and 300 mM NaCl treatments than under non-saline and higher NaCl treatments. Electrolyte leakage, malondialdehyde (MDA), and hydrogen peroxide (H₂O₂) peaked only at 900 mM NaCl. Superoxide dismutase and glutathione reductase activities and glutathione content in both roots and shoots increased progressively with increasing salinity. Hence, growth reduction under low to moderate (150–600 mM NaCl) salinity appeared to be an induced response, while high (900 mM NaCl) salinity was injurious. Full article

Triglochin maritima, a salt-tolerant plant, has demonstrated antioxidant effects, the ability to prevent prostate enlargement, antifungal properties, and skin moisturizing benefits. This study aimed to explore the anti-melanogenic potential of the 70% ethanol extract of T. maritima (TME) along with its ethyl acetate (TME-EA) and water (TME-A) fractions. TME (10–200 µg/mL), TME-EA (1–15 µg/mL), and TME-A (100–1000 µg/mL) were prepared and applied to B16F10 cells with or without α-MSH for 72 h. MTT assays were used to assess cytotoxicity, and anti-melanogenesis activity was determined by measuring melanin content, conducting a tyrosinase activity assay, and evaluating the expression of melanogenesis-related genes and proteins via RT-PCR and Western blotting. HPLC-PDA was used to analyze TME and TME-EA. The IC₂₀ cytotoxicity values of TME, TME-A, and TME-EA without α-MSH, were 198.426 μg/mL, 1000 μg/mL, and 18.403 μg/mL, respectively. TME and TME-EA significantly decreased melanin and tyrosinase activity in α-MSH-stimulated B16F10 cells, with TME-EA showing comparable effects to arbutin, while TME-A showed no influence. TME-EA down-regulated melanogenesis genes (Tyr, Trp1, Dct, Mitf, Mc1r) and reduced CREB, p-38, and JNK phosphorylation while increasing ERK phosphorylation, suggesting the CREB/MAPK pathway’s role in the anti-melanogenic effect. Luteolin was identified as a potential active ingredient. TME-EA may serve as an effective cosmeceutical for hyperpigmentation improvement due to its anti-melanogenic properties. Full article

Nitrogen (N) deposition from human activities leads to an imbalance in the N and phosphorus (P) ratios of natural ecosystems, which has a series of negative impacts on ecosystems. In this study, we used 16s rRNA sequencing technology to investigate the effect of the N-P supply ratio on the bulk soil (BS) and rhizosphere soil (RS) bacterial community of halophytes in coastal wetlands through manipulated field experiments. The response of soil bacterial communities to changing N and P ratios was influenced by plants. The N:P ratio increased the α-diversity of the RS bacterial community and changed the structure of the BS bacterial community. P addition may increase the threshold, causing decreased α-diversity of the bacterial community. The co-occurrence network of the RS community is more complex, but it is more fragile than that of BS. The co-occurrence network in BS has more modules and fewer network hubs. The increased N:P ratio can increase chemoheterotrophy and denitrification processes in the RS bacterial community, while the N:P ratio can decrease the N-fixing processes and increase the nitration processes. The response of the BS and the RS bacterial community to the N:P ratio differed, as influenced by soil organic carbon (SOC) content in terms of diversity, community composition, mutualistic networks, and functional composition. This study demonstrates that the effect of the N:P ratio on soil bacterial community is different for plant roots and emphasizes the role of plant roots in shaping soil bacterial community during environmental change. Full article