Succulent Halophyte Research Articles

Halophytic succulence is a driver of the leaf non-structural carbohydrate contents in plants in the arid and hyper-arid deserts of northwestern China.

Non-structural carbohydrates (NSC), primarily sugars and starch, play a crucial role in plant metabolic processes and a plant's ability to tolerate and recover from drought stress. Despite their importance, our understanding of NSC characteristics in the leaves of plants that thrive in hyper-arid and saline environments remains limited. To investigate the variations in leaf NSC across different species and spatial scales, and to explore their possible causes, we collected 488 leaf samples from 49 native plant species at 115 sites in the desert area of northwestern China. The contents of soluble sugars (SS), starch, and total NSC were then determined. The average contents of SS, starch, and total NSC were 26.99, 60.28, and 87.27mg g-1 respectively, which are much lower than those reported for Chinese forest plants and global terrestrial plants. Herbaceous and woody plants had similar NSC levels. In contrast, succulent halophytes, a key component of desert flora, showed significantly lower leaf SS and total NSC contents than non-succulent plants. We observed a strong negative correlation between leaf succulence and SS content, suggesting a role of halophytic succulence in driving multi-species NSC pools. Environmental factors explained a minor portion of the spatial variation in leaf NSC, possibly due to the narrow climatic variation in the study area, and soil properties, particularly soil salinity, emerged as more significant contributors. Our findings increase the understanding of plant adaptation to drought and salt stress, emphasizing the crucial role of halophytic succulence in shaping the intricate dynamics of leaf NSC across diverse plant species in arid and hyper-arid environments.

Ecophysiological and nutritional characterisation of two morphotypes of Cakile maritima subsp. maritima Scop. from Puglia region, Southern Italy.

Cakile maritima subsp. maritima Scop. (sea rocket) is a succulent halophyte with significant potential as a nutritious food source, being rich in essential nutrients such as vitamins, minerals, and antioxidants. This annual species exhibits two distinct leaf morphotypes: entire lamina (EL) and pinnatifid lamina (PL). Our understanding of their ecophysiological and nutritional profiles is still limited. The present study investigated the wild EL and PL sea rocket plants from southern Italy during their vegetative stage. The bio-morphological traits (leaf mass area-LMA, dry matter and chlorophyll concentrations), main inorganic ions, key antioxidants (carotenoids, anthocyanins, phenols, flavonoids, glucosinolates, vitamin C as ascorbic and dehydroascorbic acid), and antioxidant activity (by FRAP, DPPH, ABTS assays) were analyzed. Additionally, photosynthetic gas exchange and chlorophyll fluorescence were measured. PL plants showed thicker leaves (higher LMA) and greater accumulation of photo-protective pigments (carotenoids and anthocyanins), despite similar chlorophyll levels. The PL plants also demonstrated higher photosynthetic activity, transpiration rates, and stomatal conductance, with reduced non-photochemical quenching. The EL morphotype had higher cation (K, Mg, Ca, Na) and vitamin C (135.3 mg 100 g-1 FW) concentrations, while no significant disparities were observed between the morphotypes in phenolic concentration (208.5 mg g.a.e. 100 g-1 FW), flavonoids (71.5 mg q.e. 100 g-1 FW), or glucosinolates (61 mg g-1 FW). Interestingly, while the EL type had higher vitamin C, the PL morphotype showed superior antioxidant activity (FRAP, DPPH) and seems to be better adapted to water/nutrient scarcity typical of southern Italy. Both morphotypes offer potential as high-nutritional foods, however, future research should investigate the genotype-specific production of antioxidant compounds in EL and PL plants in response to environmental stresses, including salinity for potential exploitation as a new crop.

Exploring the potentials of Sesuvium portulacastrum L. for edibility and bioremediation of saline soils.

Sesuvium portulacastrum L. is a flowering succulent halophyte in the ice plant family Aizoaceae. There are various ecotypes distributed in sandy coastlines and salty marshlands in tropical and subtropical regions with the common name of sea purslane. These plants are tolerant to salt, drought, and flooding stresses and have been used for the stabilization of sand dunes and the restoration of coastal areas. With the increased salinization of agricultural soils and the widespread pollution of toxic metals in the environment, as well as excessive nutrients in waterbodies, S. portulacastrum has been explored for the desalination of saline soils and the phytoremediation of metals from contaminated soils and nitrogen and phosphorus from eutrophic water. In addition, sea purslane has nutraceutical and pharmaceutical value. Tissue analysis indicates that many ecotypes are rich in carbohydrates, proteins, vitamins, and mineral nutrients. Native Americans in Florida eat it raw, pickled, or cooked. In the Philippines, it is known as atchara after being pickled. S. portulacastrum contains high levels of ecdysteroids, which possess antidiabetic, anticancer, and anti-inflammatory activities in mammals. In this review article, we present the botanical information, the physiological and molecular mechanisms underlying the tolerance of sea purslane to different stresses, its nutritional and pharmaceutical value, and the methods for its propagation and production in saline soils and waterbodies. Its adaptability to a wide range of stressful environments and its role in the production of valuable bioactive compounds suggest that S. portulacastrum can be produced in saline soils as a leafy vegetable and is a valuable genetic resource that can be used for the bioremediation of soil salinity and eutrophic water.

Correlation of elemental hyperaccumulation among the succulent and non-succulent halophytes of Gujarat, India

This paper presents new data on the salt tolerance and avoidance mechanisms among various groups of halophytes in India. The halophytic flora in general has positive effect of high saline environments on growth and physiology. The coastal area of the Kachchh district in Gujarat includes about 350 km of shoreline along the Gulf of Kachchh. This study presents data on the elemental accumulation mechanisms in soil and halophytic flora (succulent and non-succulents). The halophytes were divided into two groups namely succulent with thick and fleshy leaves and stems as well as non-succulents with thin leaves and stem. The succulent halophytes included species such as Salicornia brachiata, Suaeda fruticosa and Suaeda nudiflora. The non-succulent halophytes include Aeluropus lagopoides and Urochondra setulosa. Plant parts namely leaves (Phylloclade for Salicornia), stems and roots were analyzed during the monsoon season. The results of soil and plant mineral ion contents differed widely across the intertidal zones in the same habitat. Likewise, the intra species have varied in all nutrient levels and salt concentration. The accumulation of elemental concentration was high during the monsoon season in the succulent Salicornia brachiata, especially in leaves that showed Na+ reaching high up to 7.6 meq g−1, whereas Cl− was noted to be 4.34 meq g−1. In the non-succulent halophytes, the accumulation of mineral ion concentration was lower when compared to succulent plants.

Germination and sustainable cultivation of succulent halophytes using resources from a degraded estuarine area through soil technologies approaches and saline irrigation water

AbstractThe degradation of estuarine areas has been a growing concern in recent years, as these ecosystems offer several services. The Arthrocnemum and Suaeda genera produce useful compounds with various applications, which have led to their overexploitation in their native habitats. The main goal of this study is to use green technologies for sustainable cultivation of two species bioindicators of Mediterranean saltmarshes, Arthrocnemum macrostachyum and Suaeda vera, as an alternative to their overutilization. A tailored soil (TAIL) was constructed with a Saline Fluvisol (FLU), from a marginal estuarine area, and organic/inorganic residues were used as amendments, for plant cultivation. Seeds collected in natural populations were pretreated with two dormancy‐breaking treatments (H2SO4, H2O2) and germinated in FLU or TAIL. A microcosm assay using FLU or TAIL irrigated with estuarine water (VF) or three aqueous saline solutions (0, 200, or 400 mmol/L NaCl) was established. The species obtained a low percentage of seeds' germination being the highest values under substrate control (water‐soaked filter paper). The A. macrostachyum reached the highest germination percentage when seeds were pretreated with H2SO4 (20%) while the germination of S. vera was favored by the pretreatment with H2O2 (49%). Both species had the highest growth in TAIL irrigated with 0 or VF, presenting the largest stems (13–32 cm), the largest primary branches (3.5–7.2 cm), and the highest production of aerial part biomass (28–36 g). This study contributes to the sustainable cultivation of these valuable halophytes and could play an important role in the sustainable management of marginal estuarine land.

Soil-Root Relationship in a Leaf Succulent Halophyte Suaeda vera from Differently Salt-Affected Habitats

Soil-Root Relationship in a Leaf Succulent Halophyte Suaeda vera from Differently Salt-Affected Habitats

Endorhizosphere of indigenous succulent halophytes: a valuable resource of plant growth promoting bacteria

The adaptability of halophytes to increased soil salinity is related to complex rhizosphere interactions. In this study, an integrative approach, combining culture-independent and culture-dependent techniques was used to analyze the bacterial communities in the endorizosphere of indigenous succulent halophytes Salicornia europaea, Suaeda maritima, and Camphorosma annua from the natural salt marshes of Slano Kopovo (Serbia). The 16 S rDNA analyses gave, for the first time, an insight into the composition of the endophytic bacterial communities of S. maritima and C. annua. We have found that the composition of endophyte microbiomes in the same habitat is to some extent influenced by plant species. A cultivable portion of the halophyte microbiota was tested at different NaCl concentrations for the set of plant growth promoting (PGP) traits. Through the mining of indigenous halotolerant endophytes, we obtained a collection representing a core endophyte microbiome conferring desirable PGP traits. The majority (65%) of the selected strains belonged to the common halotolerant/halophilic genera Halomonas, Kushneria, and Halobacillus, with representatives exhibiting multiple PGP traits, and retaining beneficial traits in conditions of the increased salinity. The results suggest that the root endosphere of halophytes is a valuable source of PGP bacteria supporting plant growth and fitness in salt-affected soils.

Moisture content and oxidative damage determine longevity of the seeds of potential cash crop halophyte Haloxylon stocksii

Haloxylon stocksii is a succulent halophyte with high potential to become edible-oil and medicinal crop for the arid-saline lands. Studies about germination ecology and mechanisms of salinity tolerance during vegetative stage of this plant exist. However, information about longevity and biochemical changes in H. stocksii seeds during storage is absent. This study thus examined longevity, and physio-chemical attributes of the H. stocksii seeds under different storage conditions. Fresh seeds were non-dormant with ∼96% germination in water. Storage of seeds for four months had little effect on their germination in most conditions. However, storage for 8 or 12 months caused a complete germination inhibition in laboratory and field respectively. Seed moisture increased with the storage time and was positively correlated with mortality. Antioxidant activity of the seeds increased with time in all conditions, which however was inadequate to prevent oxidative damage as hydrogen peroxide and lipid peroxidation levels increased, especially with >4 months of storage. Hence, these data indicate the short longevity of the H. stocksii seeds resulting from moisture-induced oxidative damages during storage.

Transcriptome Profiling and Functional Validation of RING-Type E3 Ligases in Halophyte Sesuvium verrucosum under Salinity Stress.

Owing to their sessile nature, plants have developed a tapestry of molecular and physiological mechanisms to overcome diverse environmental challenges, including abiotic stresses. Adaptive radiation in certain lineages, such as Aizoaceae, enable their success in colonizing arid regions and is driven by evolutionary selection. Sesuvium verrucosum (commonly known as Western sea-purslane) is a highly salt-tolerant succulent halophyte belonging to the Aizoaceae family; thus, it provides us with the model-platform for studying plant adaptation to salt stress. Various transcriptional and translational mechanisms are employed by plants to cope with salt stress. One of the systems, namely, ubiquitin-mediated post-translational modification, plays a vital role in plant tolerance to abiotic stress and other biological process. E3 ligase plays a central role in target recognition and protein specificity in ubiquitin-mediated protein degradation. Here, we characterize E3 ligases in Sesuvium verrucosum from transcriptome analysis of roots in response to salinity stress. Our de novo transcriptome assembly results in 131,454 transcripts, and the completeness of transcriptome was confirmed by BUSCO analysis (99.3% of predicted plant-specific ortholog genes). Positive selection analysis shows 101 gene families under selection; these families are enriched for abiotic stress (e.g., osmotic and salt) responses and proteasomal ubiquitin-dependent protein catabolic processes. In total, 433 E3 ligase transcripts were identified in S. verrucosum; among these transcripts, single RING-type classes were more abundant compared to multi-subunit RING-type E3 ligases. Additionally, we compared the number of single RING-finger E3 ligases with ten different plant species, which confirmed the abundance of single RING-type E3 ligases in different plant species. In addition, differential expression analysis showed significant changes in 13 single RING-type E3 ligases (p-value < 0.05) under salinity stress. Furthermore, the functions of the selected E3 ligases genes (12 genes) were confirmed by yeast assay. Among them, nine genes conferred salt tolerance in transgenic yeast. This functional assay supports the possible involvement of these E3 ligase in salinity stress. Our results lay a foundation for translational research in glycophytes to develop stress tolerant crops.

Changes in leaf ecophysiological traits and proteome profile provide new insights into variability of salt response in the succulent halophyte Cakile maritima.

Natural variability of stress tolerance in halophytic plants is of significance both ecologically and in view of identifying molecular traits for salt tolerance in plants. Using ecophysiological and proteomic analyses, we address these phenomena in two Tunisian accessions of the oilseed halophyte, Cakile maritima Scop., thriving on arid and semi-arid Mediterranean bioclimatic stages (Djerba and Raoued, respectively), with a special emphasis on the leaves. Changes in biomass, photosynthetic gas exchange and pigment concentrations in C. maritima plants treated with three salinity levels (0, 100 and 300mM NaCl) were monitored for 1month. Comparative two-dimensional gel electrophoresis (2-DE) revealed 94 and 56 proteins of differential abundance in Raoued and Djerba accessions, respectively. These salinity-responsive proteins were mainly related to photosynthesis and oxidative phosphorylation (OXPHOS). Although Djerba accession showed a lower biomass productivity, it showed a slightly higher CO2 assimilation rate than Raoued accession when salt-treated. Photosynthesis impairment in both accessions under salinity was also suggested by the lower abundance of proteins involved in Calvin cycle and electron transfer. A significant increase of protein spots involved in the OXPHOS system was found in Djerba accession, suggesting an increase in mitochondrial respiration for increased ATP production under saline conditions, whereas a lesser pronounced trend was observed for Raoued accession. The latter showed in addition higher abundance of proteins involved in photorespiration. Salt-challenged plants of Djerba also likely developed mechanisms for scavenging ROS in leaves as shown by the increase in superoxide dismutase and thioredoxin, while an opposite trend was found in Raoued.

Altered water relations, selective nutrient uptake, and reduced Na+ flux make Halopeplis perfoliata an obligate halophyte

Halopeplis perfoliata, a succulent halophyte of coastal marshy habitats, was grown in a greenhouse to study its adaptive responses in terms of growth, osmoregulation, and N-metabolism following one-month exposure to salinity (0, 150, 300, and 600 mmol L-1 NaCl). Biomass was optimal in 150 mmol L-1 NaCl with unaltered malondialdehyde (MDA) levels. On the other hand, biomass remained comparable to non-saline control with some increase in MDA in 300 and 600 mmol L-1 NaCl. Osmotic potential (?S ) was maintained up to 300 mmol L-1 NaCl that correlated with an increase in succulence (SC) and lower water deficit (WD), whereas sap ?S was lowest in 600 mmol L-1 NaCl along with lower SC and high WD. Sodium level gradually increased in shoot and was higher than the root. Potassium deficiency was not observed up to high salinity. Both soluble sugars and nitrogen isotope (?15N) increased transiently in 300 mmol L-1 NaCl. Hence, modulations in water relation, selective nutrient uptake, and controlled Na+ flux appear important for salinity tolerance of H. perfoliata.

Development of suberized barrier is critical for ion partitioning between senescent and non-senescent tissues in a succulent halophyte Sarcocornia quinqueflora

Senescence of plant tissues is a physiologically synchronized process that enables an evergreen or a perennial plant to retrieve, recycle and remobilize nutrients from elder to younger tissues or upcoming seeds. The succulent perennial halophyte S. quinqueflora utilizes this process to discard excess salt being accumulated in outer tissues of their leafy stems. The exact mechanism for salt shedding in this plant, however, remains elusive. In this work we show that the plant develops two distinct types of tissues - an endodermis-like layer (suberized layer, ED), and an additional internal photosynthetic layer (IP) - to enable this process. Their potential roles toward salt-coping strategy were investigated in this study. We show that elevated salinity leads to an accelerated development of the ED, and that its development strongly affected ion partitioning between outer (senescent) and inner (non-senescent) tissues. A positive correlation between the ratio of ED to a bead diameter and the outer to inner concentration of Na+ was observed. These ratios were highest in older (basipetally-located) beads and progressively decreased towards the tip. Furthermore, the Na+/ K+ ratio in inner tissues of bottom beads at highest salinity treatments (800 and 1000 mM NaCl) that showed clear senescence symptoms was ∼1.0, indicative of complete separation of the outer and inner tissues at late developmental stage due to the fully suberized ED multilayer. A dual-sources: dual-sinks model explaining the role of the IP layer in plant adaptation to salinity is presented.

Effects of soil salinity characteristics on three habitats in inland salt marshes.

Understanding the effect of soil salinity on the diversity and species distribution of plant communities in inland salt marsh ecosystems could provide solutions for the management of regional saline soils and the protection of salt marsh wetland vegetation. A field experiment in succulent halophyte, Carex, and gramineous grass habitats in Ordos, Inner Mongolia (northwest China) was conducted to study the diversity and composition of plants in different saline habitats in inland salt marsh ecosystems. Results showed that plant diversity and species richness in the Carex habitat were significantly higher than the succulent halophyte habitat and the gramineous grass habitat (P < 0.05). Further, species abundance was higher in the succulent halophyte habitat and the Carex habitat than the gramineous grass habitat. Similar results were obtained when considering the abundance of constructive species. No significant differences in the abundance of dominant species and companion species between the gramineous grass habitat and the Carex habitat were found. We concluded that species abundance, species richness, species distribution, and plant diversity together explained the response of plant communities in different habitats to soil salinity, especially Na+ and SO42-. This highlights the importance of soil salinity for the maintenance of plant diversity and structural composition in inland salt marsh ecosystems.

Increasing salinity leads to differential growth and H2O2 homeostasis in plants produced from heteromorphic seeds of the succulent halophyte Arthrocnemum indicum

Information about responses of plants grown from heteromorphic seeds is limited and inconclusive. This is especially true of subtropical halophytes where such studies have yet to be published. Therefore, growth, water-relations, and oxidative stress mitigation of plants germinated from the heteromorphic seeds of the succulent halophyte Arthrocnemum indicum under increasing (0, 300, and 900 mM NaCl) salinity were studied. Growth of plants from only small seeds was stimulated in moderate (300 mM NaCl) salinity. High (900 mM NaCl) salinity inhibited the growth of plants emerged from both small and large sized seeds. Plants germinating from both seed sizes demonstrated similar patterns of osmotic adjustment and did not develop signs of oxidative damage under increasing salinity. However, the magnitude of hydrogen peroxide and antioxidant responses differed between plant types. Under moderate salinity, plants from small seeds showed constitutive activities of most antioxidant enzymes (except superoxide dismutase) and levels of non-enzymatic antioxidants (except ascorbate). Conversely, a decline in activities of most antioxidant enzymes and levels of most non-enzymatic antioxidants occurred in plants from large seeds. While under high salinity, increased ascorbate peroxidase, glutathione, and polyphenol levels, along with unaffected ascorbate and superoxide dismutase levels, occurred in plants from small seeds. In plants from large seeds, there were increased ascorbate and polyphenol levels, but changes to the ascorbate peroxidase levels were not observed. These results thus indicate differential growth and hydrogen peroxide homeostasis in A. indicum plants emerged from heteromorphic seeds.

Process simulation and techno-economic assessment of Salicornia sp. based jet fuel refinery through Hermetia illucens sugars-to-lipids conversion and HEFA route

Succulent halophyte Salicornia sp. was characterized to evaluate its suitability for biorefinery, as soil salinization is seen as a major agricultural issue and the demand for biofuel is increasing. Green fractionation of biomass approach was chosen, with liquid and solid fractions of the biomass considered separately. Soxhlet extractions were used to separate different biochemical groups from the pulp, and the lignocellulosic residue was hydrothermally pretreated, enzymatically hydrolyzed, mixed with an existing agricultural feedstock, and fed to black soldier fly larvae (BSFL) for sugars-to-lipids conversion. The ASTM approved route of hydroprocessed esters and fatty acids (HEFA) was applied using in silico study of processing BSFL lipids to sustainable jet fuel, using SuperPro Designer and Aspen HYSYS. Simulations and techno-economic assessment showed, with the applied process routes, inputs and production rates, the biorefinery process will be profitable in 7 years, with a biomass input flow rate of over 60 ton h−1Salicornia sp. with decreasing payback time as the biomass input flow rate increases. Therefore, Salicornia sp. feedstock and sugars-to-lipids conversion method for biorefinery and liquid fuel production can function as a feasible biorefinery process with a normalized CO2-e reduction of HEFA-SPK of 95.5% compared to similar fossil fuels.

Identification and selection of reference genes for gene expression analysis by quantitative real-time PCR in Suaeda glauca\u2019s response to salinity

Quantitative real-time polymerase chain reaction (qPCR) using a stable reference gene is widely used for gene expression research. Suaeda glauca L. is a succulent halophyte and medicinal plant that is extensively used for phytoremediation and extraction of medicinal compounds. It thrives under high-salt conditions, which promote the accumulation of high-value secondary metabolites. However, a suitable reference gene has not been identified for gene expression standardization in S. glauca under saline conditions. Here, 10 candidate reference genes, ACT7, ACT11, CCD1, TUA5, UPL1, PP2A, DREB1D, V-H+-ATPase, MPK6, and PHT4;5, were selected from S. glauca transcriptome data. Five statistical algorithms (ΔCq, geNorm, NormFinder, BestKeeper, and RefFinder) were applied to determine the expression stabilities of these genes in 72 samples at different salt concentrations in different tissues. PP2A and TUA5 were the most stable reference genes in different tissues and salt treatments, whereas DREB1D was the least stable. The two reference genes were sufficient to normalize gene expression across all sample sets. The suitability of identified reference genes was validated with MYB and AP2 in germinating seeds of S. glauca exposed to different NaCl concentrations. Our study provides a foundational framework for standardizing qPCR analyses, enabling accurate gene expression profiling in S. glauca.

Understanding the mechanistic basis of adaptation of perennial Sarcocornia quinqueflora species to soil salinity

Succulent halophytes can be used as convenient models for understanding the mechanistic basis of plant adaptation to salt stress. In this work, effects of salinity (0-1000 mM NaCl range) on growth, ion accumulation, and stomatal features were investigated in the succulent halophyte Sarcocornia quinqueflora. Elevated salinity levels up to 400 mM NaCl largely promoted dry matter yield, succulence, shoot surface area, and stomatal characteristics. Plant growth was optimal at 200 mM NaCl and reduced at concentrations exceeding 600 mM NaCl. Osmotic adjustment in a succulent shoot was achieved by a massive accumulation of inorganic ions, with Na+ and Cl- contributing approximately 85% of its osmolality, while organic compatible solutes and K+ were responsible for only approximately 15%. Shoot K+ was unchanged across the entire range of salinity treatments (200-1000 mM NaCl) and positively correlated with the transpiration rate (R=0.98). Carbohydrates were not reduced at high salinity compared to plants at optimal conditions, implying that growth retardation at severe salt dosages was attributed to limitations in a vacuolar Na+ and Cl- sequestrations capacity rather than inadequate photosynthesis and/or substrate limitation. It is concluded that the superior salt tolerance of S. quinqueflora is achieved by the effective reliance on Na+ and Cl- accumulation for osmoregulation and turgor maintenance, and efficient K+ homeostasis for adequate stomatal functioning over the entire salinity range. The above findings could be instrumental in developing strategies to improve salinity stress tolerance in perennial horticultural crops and optimize their water-use efficiency.

The endemic halophyte Sarcocornia carinata Fuente, Rufo &amp; Sánchez-Mata (Chenopodiaceae) in relation to environmental variables: elemental composition and biominerals

AimsWe propose a thorough study of the succulent halophyte Sarcocornia carinata endemic to the saline lagoons of the center of the Iberian Peninsula. We describe its elemental composition and possible seasonal variation in relation to edaphic and climatic variables, identify biominerals and analyze the distribution of salt ions and biominerals in tissue.MethodsPlants and edaphic samples were collected in the four seasons of 1 year. Soils were analyzed for their pH, EC, color, and bioavailable concentration of Na+, K+, Mg2+, Ca2+, Cl−, SO42−. Soils and plants were analyzed for their total elemental and mineralogical composition. The distribution of elements and minerals in tissues was studied by scanning electron microscopy.ResultsDespite the variations observed in the edaphic and climatic variables, the variables studied in the plants varied slightly throughout the year. In the plants, Mg was the element that reflected climatic changes the most, while the K and Ca concentrations did not vary. Salty precipitates and crystallizations were distributed mainly in the epidermis, water storage parenchyma, cortex, and vascular vessels. Several crystals observed were compatible with halite, gypsum, glushinskite and weddellite.ConclusionsThe study corroborates that inland S. carinata behaves in the same way as other littoral succulent euhalophytes and reinforces the hypothesis that the concentration of elements and quantitative abundance pattern depend largely on the main adaptation mechanisms of halophytes.

Increasing the value of Salicornia bigelovii green biomass grown in a desert environment through biorefining

Utilizing saline soil and water resources are essential in meeting future demands for food, feed, and biofuels in a world of increasing freshwater scarcity, by use of halophytes (salt-loving plants). The succulent halophyte Salicornia bigelovii Tor. was cultivated as a green biomass crop irrigated with saline aquaculture effluents, and bio-fractionation was tested as a way to improve the value of the crop. Bio-fractionation proved to be an effective way of extracting ash and nitrogen into the green juice fraction, from which a protein concentrate was produced with 15 % crude protein and 33 % ash. The fiber fraction was not found useful as fodder due to a relatively low crude protein content of 4.1 % and 10–12 % remaining ash. However, the high digestibility of the structural carbohydrates in the fiber demonstrated its potential as a feedstock for biorefining with estimated bioethanol yields around 2500 L/ha.

Transcriptome profiling and environmental linkage to salinity across Salicornia europaea vegetation

BackgroundSalicornia europaea, a succulent obligatory halophyte is the most salt-tolerant plant species in the world. It survives salt concentrations of more than 1 M. Therefore, it is a suitable model plant to identify genes involved in salt tolerance mechanisms that can be used for the improvement of crops. The changes in a plant’s gene expression in response to abiotic stresses may depend on factors like soil conditions at the site, seasonality, etc. To date, experiments were performed to study the gene expression of S. europaea only under controlled conditions. Conversely, the present study investigates the transcriptome and physicochemical parameters of S. europaea shoots and roots from two different types of saline ecosystems growing under natural conditions.ResultsThe level of soil salinity was higher at the naturally saline site than at the anthropogenic saline site. The parameters such as ECe, Na+, Cl−, Ca+, SO42− and HCO3− of the soils and plant organs significantly varied according to sites and seasons. We found that Na+ mainly accumulated in shoots, whereas K+ and Ca2+ levels were higher in roots throughout the growing period. Moreover, changes in S. europaea gene expression were more prominent in seasons, than sites and plant organs. The 30 differentially expressed genes included enzymes for synthesis of S-adenosyl methionine, CP47 of light-harvesting complex II, photosystem I proteins, Hsp70 gene, ATP-dependent Clp proteases, ribulose bisphosphate carboxylase/oxygenase (Rubisco), phenylalanine ammonia-lyase (PAL), cytochrome c oxidase (COX) and ATP synthase.ConclusionThe comparisons made based on two seasons, plant organs and two different sites suggest the importance of seasonal variations in gene expression of S. europaea. We identify the genes that may play an important role in acclimation to season-dependent changes of salinity. The genes were involved in processes such as osmotic adjustment, energy metabolism and photosynthesis.