Search Results (40)

Tetragonia tetragonioides, or New Zealand spinach, is a widespread halophyte native to eastern Asia, Australia, and New Zealand, and naturalized in some Mediterranean regions. This underutilized vegetable is consumed for its leaves, raw or cooked. For the first time, we investigated the feasibility of using whole baby plants (including stems and leaves) as raw material for ready-to-eat (RTE) vegetable production. Our study assessed Tetragonia’s suitability for hydroponic cultivation over two cycles (autumn–winter and spring). We investigated the impact of increasing nutrient rates (only water, half-strength, and full-strength nutrient solutions) and plant densities (365, 497, and 615 plants m⁻² in the first trial and 615 and 947 plants m⁻² in the second) on baby plant production. We also analyzed the plants’ morphological and biochemical characteristics, and their viability for cold storage (21 days at 4 °C) as a minimally processed product. Tetragonia adapted well to hydroponic cultivation across both growing periods. Nevertheless, climatic conditions, plant density, and nutrient supply significantly influenced plant growth, yield, nutritional quality, and post-harvest storage. The highest plant density combined with the full-strength nutrient solution resulted in the highest yield, especially during spring (1.8 kg m⁻²), and favorable nutritional characteristics (β-carotene, Vitamin C, Fe, Cu, Mn, and Zn). Furthermore, Tetragonia baby plants proved suitable for minimal processing, maintaining good quality retention for a minimum of 14 days, thus resulting in a viable option for the RTE vegetable market. Full article

Crithmum maritimum L. is a halophyte with antioxidant and antimicrobial potential for the food industry. Pruning generates a by-product composed of woody stems, old leaves, and flowers. To valorize this underutilized and largely unexplored biomass, food-grade polar extraction (hydroethanolic vs. aqueous) was applied. The extracts were characterized for their bioactive compounds (polyphenols, tocopherols, carotenoids, total phenols (TPC) and total flavonoids (TFC)). Further, the extracts were assessed for their in vitro antioxidant activity (ABTS, DPPH, FRAP, and β-carotene bleaching) and antimicrobial activity against eight target strains ascribed to Escherichia coli, Staphylococcus aureus, and Listeria innocua. The hydroethanolic extract exhibited higher concentration of bioactives compared to the water extract and raw by-product. The β-carotene bleaching test revealed that both extracts are potent inhibitors of lipid peroxidation. The aqueous extract showed no antimicrobial activity, while the ethanolic extract exhibited strain-dependent behavior against S. aureus and L. innocua but not E. coli. The minimum inhibitory concentration and the minimum bactericidal concentration of the ethanolic extract against S. aureus were 2.5 MIC and 10.0 MBC mg/mL, respectively. Ethanolic extracts could potentially be used in food formulations to enhance lipid peroxidation resistance and antimicrobial capacity as food-grade natural preservatives. Full article

The Mediterranean region is experiencing severe droughts and unprecedented high temperatures. In terms of salinity, about 18 million ha of land, or 25% of the total irrigated area in the Mediterranean, is salt affected. The use of halophytes as intercropping species to mitigate the effects of salt stress is attractive. Halophytes have a great capacity to maintain their productivity in this extreme environment, thus supporting climate-appropriate agriculture. The aim of this study was to evaluate the productivity of Salicornia europaea L. subsp. ramosissima (glasswort) under field conditions and high soil salinity, grown as a sole crop (monocropping) and as a companion crop (intercropping) with Beta vulgaris L. subsp. cicla (Swiss chard) in a 1:1 cropping pattern. The field trials were conducted in the coastal wetland “King’s Lagoon”, a private nature reserve in the Apulia/Puglia region (southern Italy), during two consecutive spring–summer seasons in 2023 and 2024 and under different management conditions of irrigation and fertilization. These were performed to test for possible interaction effects. The results showed that both glasswort and chard can be grown sustainably under slightly saline conditions (ECe range 4–8 dS m⁻¹). In contrast, strongly saline conditions (ECe > 16 dS m⁻¹) were prohibitive for chard, both as a sole crop and as an intercrop, but were largely beneficial for glasswort. Swiss chard can benefit from intercropping with glasswort when soil salinity is still tolerable (6.9 dS m⁻¹), showing an LER (Land Equivalent Ratio) ≥ 1.19. Meanwhile, glasswort did not significantly improve the growth of the companion crop (Swiss chard) when the soil was considerably saline (16.6 dS m⁻¹). Higher LER values were observed when the contribution of chard to the intercrop performance was significantly greater than that of glasswort, i.e., under slightly saline conditions. This means that glasswort can have a significant positive effect on chard growth and productivity as long as soil is still moderately saline. Glasswort can therefore be considered a valuable model crop in extreme environments. The integration of glasswort (possibly together with other local halophytes) into diversified cropping systems on saline marginal soils is a promising sustainable agricultural practice in environmentally fragile areas such as wetlands, swamps, brackish areas, and marshes. Full article

Salinity is an increasing problem for agriculture. Most plant species tolerate low or, at best, moderate soil salinities. However, a small (<1%) proportion of species, termed halophytes, can survive and complete their life cycle in natural habitats with salinities equivalent to 200 mM NaCl or more. Cakile maritima is a succulent annual halophyte belonging to the Brassicaceae family; it is dispersed worldwide and mainly grows in foreshores. Cakile maritima growth is optimal under slight (i.e., 100 mM NaCl) saline conditions, measured by biomass and seed production. Higher salt concentrations, up to 500 mM NaCl, significantly impact its growth but do not compromise its survival. Cakile maritima alleviates sodium toxicity through different strategies, including anatomical and morphological adaptations, ion transport regulation, biosynthesis of osmolytes, and activation of antioxidative mechanisms. The species is potentially useful as a cash crop for the so-called biosaline agriculture due to its production of secondary metabolites of medical and nutritional interest and the high oil accumulation in its seeds. In this review, we highlight the relevance of this species as a model for studying the basic mechanisms of salt tolerance and for sustainable biosaline agriculture in the context of soil salination and climate change. Full article

Sustainable crop production requires an innovative approach due to increasing soil salinisation and decreasing freshwater availability. One promising strategy is the domestication of naturally salt-tolerant plant species with commercial potential. Sarcocornia fruticosa is a highly salt-tolerant halophyte, common in Mediterranean marshes, which may hold promise for biosaline agriculture. This study included 11 populations of this species spread over the territory of the Valencian Community in eastern Spain. Climatic data for each locality were obtained from the nearest meteorological stations. Soil analyses included texture, pH, electroconductivity, organic carbon and organic matter. Biochemical analyses on wild-sampled plant material focused on antioxidant compounds, such as carotenoids, phenolics, flavonoids and proline with malondialdehyde (MDA) used as a marker of oxidative stress. All variables (climatic, edaphic and biochemical) were evaluated together using Principal Component Analysis and Spearman correlation. The results obtained indicated some climatic differences in terms of mean annual precipitation, with a clear N-S gradient and considerable edaphic variability. However, none of the environmental conditions showed a clear correlation with plant biochemical characteristics. Significant differences in the levels of phenolic compounds, flavonoids and MDA between populations were probably due to genetic factors and cannot be explained as a response to environmental conditions. Full article

Wild edible plants, botanically defined as phytoalimurgical species, have historically been a useful source of food to cope with recurrent famines and poor farming conditions. If properly identified, harvested, transformed and promoted, alimurgical plants could further enhance the wellbeing of rural and urban communities and the multifunctional productivity of agriculture. The research aimed to survey alimurgical species in a wetland, map their location, detect their spatial richness, and develop a monitoring plan for ongoing vegetation succession. The study area is the King’s Lagoon, a wetland that has recently undergone a radical restoration of its natural layout. A satellite image was used to create a land cover map and interpret the relationship between plant species and land cover. The survey provided a snapshot of the wetland’s current ecosystem status and used botanical analysis and ecological indices to investigate biodiversity levels. The alpha, beta and gamma levels of biodiversity were explored and interpreted through the statistical processing of a comprehensive dataset of species occurrence and abundance, together with the calculation of Shannon’s, Simpson’s and Jaccard’s indices. It was observed that biodiversity in the wetland is developing gradually following restoration and is expected to increase over time as successional stages take hold. Biodiversity is more pronounced along the banks of the canals and watercourses connecting the basins and open ponds, while it is less pronounced in areas where the soil has been disturbed by previous excavations. Salicornia spp., Beta vulgaris subsp. maritima and Suaeda vera were identified as the most common and interesting species found in the study area. The potential for cultivation of some of the halophyte species that were monitored was also highlighted, with particular reference to the selection of the most commercially interesting species, the best species associations and intercropping practices in a wetland context, which must always prioritize the conservation of wild biodiversity. The spring surveys should be repeated in the coming years in order to accurately trace the dynamics of the ecological succession of this particular ecosystem, once it has returned to its natural development. Full article

There is still a need to investigate the relationships between glycophytes and halophytes and the many biotic and abiotic factors in their natural environments. Therefore, we study the effects of the type of environment on the ecophysiological responses and condition of the glycophyte Elder Sambucus nigra L., the macrophyte Common Reed Phragmites australis (Cav.) Trin. ex Steud., the facultative halophyte Weeping Alkaligrass Puccinellia distans (Jacq.) Parl, and the obligate halophyte Common Glasswort Salicornia europaea L. in a saline-disturbed anthropogenic region of central Poland. We analyzed the effects of salinity, acidity, and soil organic matter on shoot length, lipoperoxidation, and proline in roots and green parts, and evaluated plant responses to environmental disturbance, which allowed for the comparison of adaptation strategies. The studies were carried out in (1) “sodium production” (near sodium factories), (2) “anthropogenic environments” (waste dumps, agroecosystems, calcium deposits, post-production tanks), (3) “wetland environments” (near river channels and riparian areas), and (4) “control” (natural, unpolluted environments). Green parts of plants are better suited to indicate environmental stress than roots. Their higher structural MDA membrane damage is related to the transport of toxic ions to the shoots by a rapid transpiration stream in the xylem. We found high salinity to be the main factor inducing growth and found it to be correlated with the high pH effect on proline increase in glycophytes (Elder, Reed) and Weeping Alkaligrass, in contrast to Common Glasswort. We suggest that proline accumulation allows osmotic adjustment in the green parts of reeds and alkaligrasses, but may have another function (in Elder). Common Glasswort accumulates large amounts of Na⁺, which is energetically more effective than proline accumulation for osmotic adjustment. Organic matter affects plant growth and proline levels, but soil salinity and pH alter nutrient availability. Plant distribution along the salinity gradient indicates that Elder is the most salt-sensitive species compared to Reed, Alkaligrass, and Glasswort. Salinity and the lack of control of thick reeds, which compete with other plant groups, affect the distribution of halophytes in saline environments. Full article

The discovery of new natural products has become more challenging because of the re-isolation of compounds and the lack of new sources. Microbes dwelling in extreme conditions of high salinity and temperature are huge prospects for interesting natural metabolites. In this study, the endophytic bacteria Bacillus velezensis 7NPB-3B isolated from the halophyte Salicornia brachiata was screened for its biofilm inhibition against methicillin-resistant Staphylococcus aureus (MRSA). The fractionation of the crude extract was guided by bioassay and LC-HRMS-based metabolomics using multivariate analysis. The 37 fractions obtained by high-throughput chromatography were dereplicated using an in-house MS-Excel macro coupled with the Dictionary of Natural Products database. Successive bioactivity-guided separation yielded one novel compound (1), a diketopiperazine (m/z 469.258 [M − H]⁻) with an attached saturated decanoic acid chain, and four known compounds (2–5). The compounds were identified based on 1D- and 2D-NMR and mass spectrometry. Compounds 1 and 5 exhibited excellent biofilm inhibition properties of >90% against the MRSA pathogen at minimum inhibition concentrations of 25 and 35 µg/mL, respectively. The investigation resulted in the isolation of a novel diketopiperazine from a bacterial endophyte of an untapped plant using an omics approach. Full article

The revalorization of natural resources in food production is increasing, and the effect of climate change is negatively affecting the production of conventional crops. In recent years, edible halophytes have received more attention due to their ability to tolerate a wide range of salinities. Thus, the use of halophytes that require less water and are strongly adapted to high-salinity soil and coastal areas can provide sustainable agriculture in certain areas. In addition, there is growing interest in the study of the possibilities that these species offer as foods due to their excellent nutritional profile and antioxidant properties. For that reason, the exploitation of plants adapted to these areas is nowadays even more important than in the past to guarantee food security in arid or semiarid salinized territories. The available data about the nutrients and bioactive compounds composition of many non-cultivated edible vegetables traditionally used in the Mediterranean area, such as Salicornia edible young shoots, are still scarce. With the aim of improving the knowledge on their nutritional value, the present study provides new data about the content of some compounds with biological activity, such as fiber and organic acids, in eight samples of young shoots of S. patula Duval-Jouve gathered in great mainland and coastal salt marshes in Southwest and Central Spain. Results showed that this vegetable can be considered a healthy food and a very good source of dietary fiber (4.81–6.30 g/100 g fw total fiber). Its organic acid profile showed oxalic, malic, citric and succinic acids. Oxalic acid was the major one, with mean values of 0.151–1.691 g/100 g fw. From the results obtained in this study, S. patula shoots could be recommended as an alternative source of fiber for healthy and sustainable diets in the general adult population with no risk of renal disease. Full article

Saline agriculture, including the commercial cultivation of edible halophytes, is expanding rapidly to address the increase in salinised soil due to natural and man-made causes, the decline in availability of fresh water, the increased use of poor-quality water, and increasing food insecurity. Halophytes, as food crops, offer an innovative new opportunity in agriculture, many being highly nutritious and containing bioactive compounds. However, the commercial production of edible halophytes to meet emerging consumer demands faces several challenges. This review examines the market potential for the expansion of edible halophyte crops and the challenges of consumer acceptance and production capacity beyond wild harvest. In addition to beneficial compounds, halophytes are known to contain several anti-nutrient compounds, which can have negative health consequences. In edible halophytes, oxalates are of particular concern. However, research has shown that there are ways to mitigate the accumulation of oxalate through processing, agronomic practice, and genetic engineering. These approaches are presented as potential strategies that can be used in commercial farming systems to reduce the levels of this compound. Full article

The salinization of soils is a growing agricultural concern worldwide. Irrigation practices, drought, and climate change are leading to elevated salinity levels in many regions, resulting in reduced crop yields. However, there is potential for a solution in the microbiome of halophytes, which are naturally salt-tolerant plants. These plants harbor a salt-tolerant microbiome in their rhizosphere (around roots) and endosphere (within plant tissue). These bacteria may play a significant role in conferring salt tolerance to the host plants. This leads to the possibility of transferring these beneficial bacteria, known as salt-tolerant plant-growth-promoting bacteria (ST-PGPB), to salt-sensitive plants, enabling them to grow in salt-affected areas to improve crop productivity. In this review, the background of salt-tolerant microbiomes is discussed and their potential use as ST-PGPB inocula is explored. We focus on two Gram-negative bacterial genera, Halomonas and Kushneria, which are commonly found in highly saline environments. These genera have been found to be associated with some halophytes, suggesting their potential for facilitating ST-PGPB activity. The study of salt-tolerant microbiomes and their use as PGPB holds promise for addressing the challenges posed by soil salinity in the context of efforts to improve crop growth in salt-affected areas. Full article

Carpobrotus edulis (L.) N.E.Br. (Hottentot-fig) is a problematic invasive species found in coastal areas worldwide. Mechanical removal is a common control method, leaving the removed biomass available as a possible source of natural phytochemicals with prospective commercial applications. While the Hottentot-fig’s vegetative organs have been studied previously, this work establishes for the first time a seasonal and spatial comparative analysis of its nutritional, chemical, and bioactivity profiles (in three locations over four seasons). Proximate and mineral contents were assessed, along with its phenolic composition and in vitro antioxidant and anti-inflammatory properties. Hottentot-fig’s biomass offered a good supply of nutrients, mainly carbohydrates, proteins, and minerals, with a tendency for higher concentrations of the most relevant minerals and proteins in autumn and winter, and in plants from sites A (Ria de Alvor lagoon) and B (Ancão beach). The extracts were rich in polyphenolics, with higher levels in spring and summer, especially for luteolin-7-O-glucoside and salicylic and coumaric acids. The extracts were also effective antioxidants, with stronger radical scavenging activities in spring and summer, along with anti-inflammatory properties. Our results suggest that the usually discarded plant material of this invasive halophyte could be valuable as a source of natural products with potential biotechnological applications in the food and nutraceutical industries. Full article

Saline ecosystems are often the target of spills and releases of pollutants such as metals, as many industrial companies settle in or around these areas. Metal pollution is a major threat for humans and ecosystems. In line with sustainable development, nature-based solutions and biological tools such as phytoremediation offer eco-friendly and low-cost solutions to remove metals or limit their spread in the environment. Many plant-growth-promoting (PGP) effects are frequently prospected in plant-associated microbes such as the production of auxins, siderophores, or extracellular polymeric substances to enhance phytoremediation. Halophytes are nowadays presented as good phytoremediators for metal-contaminated saline environments such as coastal regions, but little is known about the potential of their associated microbes in the bioaugmentation of this technique. Here, we review the studies that focused on halophytes-associated microbes and their plant-growth-promotion capacities. Moreover, we discuss the limitation and applicability of bioaugmented phytoremediation in saline ecosystems. Full article

With the increasing shortage of water resources, the current management of saline–alkali lands in semi-arid and arid areas has gradually transformed from “flooding irrigation with drainage” in the past to the combination of controlling regional water and salt balance, phytoremediation, and comprehensive utilization of halophyte resources. However, soil salinization caused by natural and anthropogenic factors has still been a major global environmental problem, which changes the chemical and physical properties of soil, deteriorates the quality of underground water, and decreases biodiversity, contributing to the loss of soil productivity and the succession of the halotolerant species. Euhalophytes, as the materials for phytoremediation, have been confirmed to be effective species in improving saline–alkali soils. They can redistribute salts in soil profile through the interaction of their desalinization potential and irrigation water leaching, thereby preventing secondary salinization and improving soil productivity for long-term reclamation of saline soil. In this review, the adaptation mechanisms of euhalophytes to saline soils are generalized from the views of morphological, physiological, and molecular aspects and evaluated for their potential to remediate saline soil through salt removal and promoting leaching. Euhalophytes can not only sequestrate salts inside the central vacuole of cells to tolerate higher salt stress by means of organ succulence, ion compartmentalization, and osmotic adjustment but facilitate water infiltration and salts leaching through root–soil interaction. The root system’s mechanical penetration increases soil porosity, decreases soil density, as well as stabilizes soil aggregates. Moreover, the suitability of phytoremediation in arid situations with low precipitation and non-irrigation and some agricultural practices need to be taken into account to avoid salts returning to the soil as forms of litter and deep tillage altering salt distribution. Hence, euhalophytes planting in semi-arid and arid areas should be evaluated from their adaptation, desalinization, and prospective commercial values, such as foods, biofuels, and medical development to alleviate soil secondary salinization crisis and enhance the productivity of arable agricultural land. Full article

Halophytes, wild plants adapted to highly saline natural environments, represent extremely useful—and, at present, underutilised—experimental systems with which to investigate the mechanisms of salt tolerance in plants at the anatomical, physiological, biochemical and molecular levels. They can also provide biotechnological tools for the genetic improvement of salt tolerance in our conventional crops, such as salt tolerance genes or salt-induced promoters. Furthermore, halophytes may constitute the basis of sustainable ‘saline agriculture’ through commercial cultivation after some breeding to improve agronomic traits. All these issues are relevant in the present context of climate emergency, as soil salinity is—together with drought—the most critical environmental factor in reducing crop yield worldwide. In fact, climate change represents the most serious challenge for agricultural production and food security in the near future. Several of the topics mentioned above—mainly referring to basic studies on salt tolerance mechanisms—are addressed in the articles published within this Special Issue. Full article