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Endophytic bacteria have not been reported widely for their lipolytic abilities, so they are not used for large‐scale lipase production. The purpose of this study was to explore an endophytic bacterium for the production of lipase implementing cost‐effective techniques, including the use of Cassia fistula seeds, as a substrate in the production medium and stem pieces of Phragmites karka as the immobilization matrix. The endophytic strain Bacillus sp. E4 was originally isolated from the halophytic plant Arthrocnemum macrostachyum. Bacillus sp. E4 produced 6.05 IU mL−1 lipase in the presence of powdered seeds of Cassia fistula (golden shower tree). Initial trial experiments using a one‐factor‐at‐a‐time approach led to an improvement in lipase titers to 10.05 IU mL−1. Consequently, investigations using the Plackett–Burman design suggested the influence of three significant factors – incubation period, inoculum size, and substrate concentration – on lipase production. They were optimized using the Box–Behnken design (BBD). In the response optimization experiment, strain E4 yielded 52.35 IU mL−1 lipase, which was in accordance with the predicted yield and indicated an overall 8.65 fold improvement in lipase production. To investigate the use of free cells, strain E4 was immobilized on the stem pieces of a halophytic plant, Phragmites karka, which was used for the first time as an immobilization matrix. The immobilized cells retained lipase production ability for up to six cycles with the highest yield of 110 IU mL−1, which corresponded to an improvement of more than eighteenfold. Scanning electron micrographs confirmed the colonization of E4 cells in the matrix and demonstrated the utilization of C. fistula seeds. Fourier transform infrared spectroscopy affirmed the utilization of components including fatty acids by the immobilized E4 cells. The study suggests that endophytic bacterial strains could be applied for the production of lipase with the utilization of nontraditional oil sources. [ABSTRACT FROM AUTHOR]

The 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. [ABSTRACT FROM AUTHOR]

Background: Indiscriminate use of conventional antibiotics has become a major factor responsible for the emergence and dissemination of multidrug-resistant strains of microorganisms. In this regard, we analyzed the plant extracts as an alternative solution for the inhibition of the resistant bugs. Methodology: This study was planned to investigate the antifungal, antibacterial and anti-inflammatory activities of hexane, ethyl acetate, chloroform, and methanol extracts of Arthrocnemum macrostachyum. Soxhlet apparatus was used to prepare different extracts of the whole plant using hexane, ethyl acetate, chloroform, and methanol. The antifungal and antibacterial activity was analyzed with the help of a good diffusion technique using different concentrations of plant extracts. The anti-inflammatory activity was also checked by observing the inhibition of albumin denaturation. Results: Maximum antifungal activity was observed by hexane, methanol, and chloroform extracts, and maximum antibacterial activity showed by the methanol extract. The most sensitive fungi found were Mucor, Aspergillus flavus, Saccharomyces, and Candida. Trichophyton mentagrophytes were found resistant to all the extracts. The most sensitive bacterial isolates found were Salmonella typhi, Proteus mirabilis, Pseudomonas aeruginosa, and Citrobacter freundii. The most resistant organisms were Streptococcus fecalis and Shigella dysenteriae. Methanol and chloroform extracts produced observable anti-inflammatory potential by inhibiting albumin denaturation. Statistical analysis was performed on SPSS version 23.0. Conclusion: The plant extracts showed significant antifungal, antibacterial and anti-inflammatory activity. These findings may support using the Arthrocnemum macrostachyum whole plant as an anti-inflammatory, antibacterial, and traditional antifungal plant. Our results demonstrate that this plant has considerable therapeutic effects on potential infectious agents and can be used to alternative conventional medicines.

Salinity negatively influences crop growth, but several salt-tolerant plant species (halophytes) are viable crops. Sarcocornia fruticosa (ecotypes EL and VM) is currently cultivated, but there is demand for new crop candidates and higher biomass production. Salicornia brachiata Roxb. and Arthrocneum macrostachyum L. are considered novel crops, and to realize their potential, their response to salinity and nitrogen nutrition was compared to S. fruticosa ecotypes. Experiments revealed that higher N supplemented with lower NaCl significantly increased fresh and dry shoot biomass. Lower biomass was obtained at lower nitrogen supplemented with elevated NaCl, whereas total soluble solids content positively correlated with NaCl fertigation in both Sarcocornia ecotypes. Protein content increased with a lower nitrogen supply. Anthocyanins and oxygen radical absorbance capacity were highest in S. fruticosa EL and A. macrostachyum at higher NaCl supply. The results show that halophytes have a variety of strategies to cope with high NaCl, even between ecotypes of the same species. Notably, repetitive harvesting of S. brachiata delayed flowering enabling year-round biomass production. Additionally, S. brachiata accumulated higher biomass than Sarcocornia VM when grown in a greenhouse at higher radiation than in a growth room and strongly supports its inclusion as a cash-crop halophyte. [ABSTRACT FROM AUTHOR]

Antimicrobial activity of hydroalcoholic extracts (30/70) from leaves and stems of three halophytes (Tamarix africana, Arthrocnemum macrostachyum and Suaeda fruticose) was investigated. In vivo toxicological study and anti-inflammatory activity of leaf extract of T. africana were tested on carrageenan-induced inflammatory paw edema. T. africana possessed significant anti-inflammatory activity at 150 and 300 mg/kg confirmed by histological study of inflamed tissues. Six phenolic acids and 10 flavonoids where identified by HPLC–DAD. Gallic acid, Rutin and Kaempferol-3-O-glucoside were the major compounds. For the antibiotic assays, S. fruticosa leaf extract exhibited strong bactericidal power against S. aureus with MBC of 1.25 mg/mL whereas T. africana leaf and stem samples exhibited a significant bactericidal activity against S. aureus and B. subtilis compared to the negative control (Ampicillin and Chloramphenicol). Crude leaf and stem extracts from T. africana and stem extract from S. fruticosa exhibited a strong antifungal effect against C. albicans. [ABSTRACT FROM AUTHOR]

Salinity negatively influences crop growth, but several salt-tolerant plant species (halophytes) are viable crops. Sarcocornia fruticosa (ecotypes EL and VM) is currently cultivated, but there is demand for new crop candidates and higher biomass production. Salicornia brachiata Roxb. and Arthrocneum macrostachyum L. are considered novel crops, and to realize their potential, their response to salinity and nitrogen nutrition was compared to S. fruticosa ecotypes. Experiments revealed that higher N supplemented with lower NaCl significantly increased fresh and dry shoot biomass. Lower biomass was obtained at lower nitrogen supplemented with elevated NaCl, whereas total soluble solids content positively correlated with NaCl fertigation in both Sarcocornia ecotypes. Protein content increased with a lower nitrogen supply. Anthocyanins and oxygen radical absorbance capacity were highest in S. fruticosa EL and A. macrostachyum at higher NaCl supply. The results show that halophytes have a variety of strategies to cope with high NaCl, even between ecotypes of the same species. Notably, repetitive harvesting of S. brachiata delayed flowering enabling year-round biomass production. Additionally, S. brachiata accumulated higher biomass than Sarcocornia VM when grown in a greenhouse at higher radiation than in a growth room and strongly supports its inclusion as a cash-crop halophyte.

Arthrocnemum macrostachyum (Moric.) Moris. & Delponte perennial succulent halophyte shrub suffered from taxonomic confusion. Thereby, the present study focused on phylogenetic relationships investigation among three A. macrostachyum genotypes grown along the Syrian coast. DNA polymorphism of A. macrostachyum has been investigated based on touch-down directed amplification of minisatellite DNA (Td-DAMD) and touch up-directed amplification of minisatellite DNA (TU-DAMD) markers in comparative study. Seventeen DAMD primers were tested for each TD-DAMD and TU-DAMD assesses. Comparative study revealed that TU-DAMD assay was more potent than TD-DAMD one by exhibiting the highest polymorphism level (P%) 92.035% & 87.805% of and polymorphic information content (PIC) values of and 0.411 and 0.386, for TU-DAMD and TD-DAMD, respectively. Clustering profile constructed based on the both examined assesses gave similar pattern; where, A. macrostachyum2 genotype was genetically so far from the other two genotypes. Thereby, the actual data confirmed previous reports suggesting the existence of two subspecies belonged to A. macrostachyum species. Otherwise, Due to efficacy of TU-DAMD for genetic variation revealing of A. macrostachyum species; it is advice to employ this technique as a new assay in phylogenetic studies of other plant species. [ABSTRACT FROM AUTHOR]

ARTHROCNEMUM macrostachyum is a halophyte naturally growing on Manzala Lake shoreline of Egypt and able to tolerate and accumulate heavy metals. The use of metalresistant rhizobacteria is an important technology to improve the tolerance capability of the halophytes in metal-polluted environments. A total of 33 bacterial isolates were obtained from the root system of A. macrostachyum and screened for resistance to 1.25 and 12.5mM of Cr(VI) in plant-based culture medium prepared from the halophyte shoot juice. The six most tolerant isolates were identified based on cell morphology and API microtube profiles. Those isolates were found closely related to Bacillus lentus, Burkholderia cepacia, Raoultella ornithinolytica and Providencia retgeri indicated on the online database. Among the strains tested for their ability to accumulate chromium, Bacillus lentus was the most effective with an average accumulation percentage of 17.8, Providencia retgeri ranked thereafter (15.1%). Bacillus circulance was the least with a negligible accumulation level of 0.5%. The biosorption rate of the heavy metal was contact time- and bacterial strain-dependent. Again, Bacillus lentus showed the highest uptake capacity of 32.8mg g-1, a parameter that positively correlated with contact time (r= 0.865), this was not the case with Burkholderia cepacia where the correlation was negative (r= - 0.811). When introduced into an aqueous solution of 25mg L-1 Cr(VI), Burkholderia cepacia was the superior in Cr(VI) reduction (86.7%), while Bacillus circulance failed to reduce the heavy metal. The pH 5.5 was the most favorable for bacterial Cr accumulation which proportionally decreased as the acidity of the solution increased. This study provides more understanding of the significant contribution of the heavy metal-tolerant microbiome to improve the metal remediation efficiency of halophytic plant covers of stressed environments. [ABSTRACT FROM AUTHOR]

We studied the capacity of extreme halophyte, Arthrocnemum macrostachyum , to desalinize an experimentally-salinized soil under non-leaching conditions. Furthermore, we tested the effect of salt pre-exposure of this species on its phytodesalination capacity. The presence of the halophyte, independently salt pre-exposure, decreased salinity of the sanilized soil by 31% after 30 days; reducing the negative effects on emergence of both test cultures, barley and wheat. Plants of A. macrostachyum pre-treated without salt showed 4-fold higher relative desalination rate than those grown with optimum salinity (with higher initial biomass). Thus, previous salt exposure was as determinant as plant biomass for desalinizing capacity. In conclusion, pre-exposure to salt of halophytes must be taken into account for desalination programs. • A. macrostachyum is a halophyte of great interest for desalination programs. • The halophyte culture allowed the emergence of barley and wheat seeds. • Plants grown without salt showed higher relative phytodesalination rate. • Previous experience to salt was as determinant as the phytodesalinizing biomass. [ABSTRACT FROM AUTHOR]

Although little is known about their nutritional composition, Sarcocornia perennis subsp. perennis , S. perennis subsp. alpini and Salicornia ramosissima (Salicorniaceae) as well as Arthrocnemum macrostachyum (Amaranthaceae) are consumed in gourmet cuisine. In spite of belonging to different families, these halophytes share morphological and organoleptic characteristics. This work explored the nutritional properties and the antioxidant potential of these species using five integrative methods. All species had a nutritional profile suitable for human consumption with high levels of protein (5.20–13.2 g/100 g dw) and n -3 polyunsaturated fatty acids (FA), particularly α-linolenic acid (19.3–25.9% of total FA), and low concentration of toxic metals (below the limits imposed by the European Commission). These halophytes are also a good source of minerals, particularly sodium (64.1–109 mg/g dw), and S. ramosissima is an excellent source of manganese (204 μg/g dw). However, due care should be taken not to exceed the legal limits for sodium ingestion. These plants showed also significant antioxidant potential, with high radical scavenging activity (RSA), iron reducing power and total phenolics content (20.5–49.2 mg GAE/g). A. macrostachyum had the highest RSA (IC 50-DPPH = 0.84 mg/mL; IC 50-NO = 0.60 mg/mL), and iron reducing potential (IC 50 = 0.84 mg/mL) along with high levels of α- and γ -tocopherol (8.74 and 4.71 mg/100 g dw, respectively). [ABSTRACT FROM AUTHOR]

A glasshouse experiment was designed to investigate the role of bacterial consortia isolated from the endosphere (CE) and rhizosphere (CR) of Arthrocnemum macrostachyum on its metal uptake capacity and tolerance in plants grown in metal polluted sediments. A . macrostachyum plants were randomly assigned to three bioaugmentation treatments (CE, CR and without inoculation) during 120 days. Bioaugmentation with both bacterial consortia enhanced A . macrostachyum capacity to accumulate ions in its roots, while shoot ions concentration only increased with CE treatment. Furthermore bioaugmentation ameliorated the phytotoxicity levels, which was reflected in an increment of plant growth of 59 and 113% for shoots and 52 and 98% for roots with CE and CR treatments, respectively. This effect was supported by bacteria beneficial effect on photochemical apparatus and the modulation of its oxidative stress machinery. These findings indicated that bacteria selected from the microbiome can be claimed to improve A . macrostachyum metal remediation efficiency. [ABSTRACT FROM AUTHOR]

Coastal ecosystems produce and sequester significant amounts of carbon ('blue carbon'), which has been well documented in humid and semi-humid regions of temperate and tropical climates but less so in arid regions where mangroves, marshes, and seagrasses exist near the limit of their tolerance for extreme temperature and salinity. To better understand these unique systems, we measured whole-ecosystem carbon stocks in 58 sites across the United Arab Emirates (UAE) in natural and planted mangroves, salt marshes, seagrass beds, microbial mats, and coastal sabkha (inter- and supratidal unvegetated salt flats). Natural mangroves held significantly more carbon in above- and belowground biomass than other vegetated ecosystems. Planted mangrove carbon stocks increased with age, but there were large differences for sites of similar age. Soil carbon varied widely across sites (2-367 Mg C/ha), with ecosystem averages that ranged from 49 to 156 Mg C/ha. For the first time, microbial mats were documented to contain soil carbon pools comparable to vascular plant-dominated ecosystems, and could arguably be recognized as a unique blue carbon ecosystem. Total ecosystem carbon stocks ranged widely from 2 to 515 Mg C/ha (seagrass bed and mangrove, respectively). Seagrass beds had the lowest carbon stock per unit area, but the largest stock per total area due to their large spatial coverage. Compared to similar ecosystems globally, mangroves and marshes in the UAE have lower plant and soil carbon stocks; however, the difference in soil stocks is far larger than with plant stocks. This incongruent difference between stocks is likely due to poor carbon preservation under conditions of weakly reduced soils (200-350 mV), coarse-grained sediments, and active shoreline migration. This work represents the first attempt to produce a country-wide coastal ecosystem carbon accounting using a uniform sampling protocol, and was motivated by specific policy goals identified by the Abu Dhabi Global Environmental Data Initiative. These carbon stock data supported two objectives: to quantify carbon stocks and infer sequestration capacity in arid blue carbon ecosystems, and to explore the potential to incorporate blue carbon science into national reporting and planning documents. [ABSTRACT FROM AUTHOR]

There is an increasing interest to use halophytes for revegetation of salt affected ecosystems, as well as in understanding their mechanisms of salt tolerance. We hypothesized that bacteria from the phyllosphere of these plants might play a key role in its high tolerance to excessive salinity., Eight endophytic bacteria belonging to Bacillus and closely related genera were isolated from phyllosphere of the halophyte Arthrocnemum macrostachyum growing in salty agricultural soils. The presence of plant-growth promoting (PGP) properties, enzymatic activities and tolerance towards NaCl was determined. Effects of inoculation on seeds germination and adult plant growth under experimental NaCl treatments (0, 510 and 1030 mM NaCl) were studied., Inoculation with a consortium including the best performing bacteria improved considerably the kinetics of germination and the final germination percentage of A. macrostachyum seeds. At high NaCl concentrations (1030 mM), inoculation of plants mitigated the effects of high salinity on plant growth and physiological performance and, in addition, this consortium appears to have increased the potential of A. macrostachyum to accumulate Na+ in its shoots, thus improving sodium phytoextraction capacity., Bacteria isolated from A. macrostachyum phyllosphere seem to play an important role in plant salt tolerance under stressing salt concentrations. The combined use of A. macrostachyum and its microbiome can be an adequate tool to enhance plant adaptation and sodium phytoextraction during restoration of salt degraded soils. [ABSTRACT FROM AUTHOR]

Plants growing in highly saline soils harbor unique communities of fungal root endophytes. We aimed to gain insight into how these communities are established in natural plant populations. We used cultivation-based and molecular approaches to examine root-endophytic colonization in the annual halophyte Salicornia patula at three time points over a 5-month period, from establishment to flowering. At the last sampling, the endophytic community of S. patula was compared to that in the related but perennial halophyte Arthrocnemum macrostachyum. The presence of root endophytes in S. patula was negligible at the first two sampling times, and remained low at the last sampling compared to A. macrostachyum. The latter species showed a well-established endophytic community in its roots that differed from that in S. patula, which was dominated by members of Pleosporales. Although such differences could be partially due to the host lifestyle, the possibility of a strong effect of the substratum could not be excluded. Altogether, our data indicate that the fungal endophytic colonization of roots is a slow process under salt stress. Therefore, we suggest that, in contrast to what is proposed for other systems, endophyte symbioses are unlikely to impact the development of the short-life-cycled S. patula living in these environments. [ABSTRACT FROM AUTHOR]

Arthrocnemum macrostachyum is a halophyte naturally growing in southwest coasts of Spain that can tolerate and accumulate heavy metals. A total of 48 bacteria (30 endophytes and 18 from the rhizosphere) were isolated from A. macrostachyum growing in the Odiel River marshes, an ecosystem with high levels of contamination. All the isolates exhibited plant-growth-promoting (PGP) properties and most of them were multiresistant to heavy metals. Although the presence of heavy metals reduced the capability of the isolates to exhibit PGP properties, several strains were able to maintain their properties or even enhance them in the presence of concrete metals. Two bacterial consortia with the best-performing endophytic or rhizospheric strains were selected for further experiments. Bacterial inoculation accelerated germination of A. macrostachyum seeds in both the absence and presence of heavy metals. These results suggest that inoculation of A. macrostachyum with the selected bacteria could ameliorate plant establishment and growth in contaminated marshes. [ABSTRACT FROM AUTHOR]

Random amplified microsatellite polymorphism (RAMP) marker technique was employed to test its usefulness for assessing phylogenetic relationships in three genotypes of Arthrocnemum macrostachyum (Moric.) Moris. & Delponte from Syria. PCR reactions with 21 RAMP primer combinations (PCs) distinguished 145 loci, 139 of which (95.862%) were polymorphic. The (AG)8TC/OPE18 primer combination generated the highest number of fragments (11 amplicons), and the (AC)8T/OPE04 primer combination the fewest (4 amplicons). Average estimated polymorphic information content (PIC) was 0.431, with an average marker index (MI) of 2.836. Analysis by the unweighted pair group method using arithmetic averages (UPGMA) was performed and a dendrogram was constructed. UPGMA cluster analysis based on RAMP markers distinguished genotype 2, suggested here to be a subspecies, from genotypes 1 and 3. In this study the RAMP marker method proved to be a reliable tool for discriminating and estimating genetic diversity within A. macrostachyum. [ABSTRACT FROM AUTHOR]

There are known culinary applications of halophytes species, such as Atriplex halimus, Portulaca oleracea, Beta maritima, Salicornia europaea and Arthrocnemum macrostachyum, mostly due to their mineral content, as they provide an alternative to common salt. Species of the last two genera possess a curious salt resistance mechanism, in which they can store Na+ in vacuoles in their shoots, using these vacuoles to stimulate growth. It is theorized that this mechanism enables the extraction of a vegetable salt, with a different Na+/Cl- ratio , providing healthier applications for human consumption, due to lower Na+ levels. In the present work we try to validate an efficient method for extracting a vegetable salt from a commercial mixture of Salicornia europaea and Salicornia bigelovii, as well as wild Arthrocnemum macrostachyum. We compared the efficiency of two extraction solvents used on this methodology. The used process presented mean yield rates around 70% (Salicornia) and 50% (Arthrocnemum). The comparison of the results between genera was the expected, since Salicornia species are more succulent than Arthrocnemum. This method yield rates in Salicornia appear to be higher than the expected based on previous publication. The data suggests other elements of interest may be differently distributed between the two genera. A nutritional profile, which we intend to do, may elucidate about the contents of vegetable salt.

Abstract: Long-term soil salinity data are required to properly manage saline habitats. This study presents easy procedures for comparing soil salinity profiles, which were used to assess four saline wetlands in NE Spain. Soil salinity measurements at sites where different halophytes were dominant were recorded throughout the year in 1979–1980 and 1999–2000, with additional measurements in 1985. Electrical conductivity of saturation extracts (ECe) and the concentrations of major ions were measured in four hundred soil samples. To confirm the consistency of the quality of the lab measurements, we used saturation percentage (SP) statistics and the relationships between ECe and both the cationic and the anionic concentrations in the extracts (R2 >97%), and the relationship with the EC of the extracts at a soil-to-water ratio of 1:5 by weight (EC 1:5). The ECe of the soil samples ranged from 4 to 114dSm−1, and the averages in the four wetlands (AN, PC, AL, and AG) were 38.6, 10.1, 22.3, and 68.5dSm−1, respectively. The median of the sodium adsorption ratio [SAR, (meqL−1)0.5] in the samples was 69, 126, 64, and 28, respectively. At AN, the maximum average ECe in the upper 100cm of the soil was 35.0dSm−1 for Artemisia herba-alba and 75.2dSm−1 for Suaeda vera; at PC, the maximum value was 19.3dSm−1 for Puccinellia festuciformis; and, at AL, it was 30.3dSm−1 for Salicornia ramosissima and 44.6dSm−1 for S. vera. At AG, the maximum average ECe was 69.2 for S. vera, and 85.2dSm−1 for Arthrocnemum macrostachyum. The ECe and SAR remained stable between the two sampling periods in three of the wetlands but, in AL, which was converted into a paddy, ECe was reduced from ~40dSm−1 to ~2dSm−1 and SAR was reduced from >77 to ~2. The presence of saline non-sodic and saline–sodic soils at nearby wetlands reflects the pedodiversity of the area. [Copyright &y& Elsevier]

Cistanche phelypaea (L.) Cout. (Orobancaceae) was found parasitising the roots of the succulent shrublets Arthrocnemum macrostachyum (Moric.) K.Koch (Chenopodiaceae) in a coastal salt marsh in Qatar. Measurements were conducted to identify soil properties, host, and noninfected plants by soil excavations to expose the haustoria of the parasite attached to the host roots. The water potential, osmotic potential, pressure potential, and chemical analyses were determined in parasite, host, and noninfected plants. Crown diameter and dry mass of the host plants were smaller than in the noninfected plants. A gradient of water potential existed between the host root and the underground tuberous body of the parasite. Potassium was the major cation found in the parasite, while sodium was dominant in the host and noninfected plants. The nitrogen, soluble sugars, total amino acids, and starch contents of the parasite were higher than those of the host and noninfected plants. The high ratio of K+ to Ca2+ in the parasite indicates that it is phloem-feeding. The high nutrient element contents and metabolic products in the parasite are possibly related to the creation of osmotic and water potential gradients between the host and C. phelypaea. [ABSTRACT FROM AUTHOR]

Abstract: Tetramethylbenzidine-H2O2 staining of SDS-polyacrylamide gel is a widely used method for the specific detection of proteins with heme-dependent peroxidase activity. When this method was used with thylakoids from the halophytic plant Arthrocnemum macrostachyum, besides the cytochrome f and cytochrome b6 proteins usually found in higher plants and cyanobacteria, at least four additional bands were detected. One of them, a 46-kDa protein, was shown to be an extrinsic protein, and identified by mass spectrometry and immunoblotting as a 2-cys peroxiredoxin. Peroxidase activity was insensitive to oxidizing agents such as trans-4,4-diydroxy-1,2-dithiane or hydrogen peroxide, but was inhibited by treatment of thylakoids with reducing agents such as dithiothreitol or mercaptoethanol. By immunoblotting, it was shown that loss of peroxidase activity was paralleled by disappearance of the 46-kDa band, which was converted to a 23-kDa immunoreactive form. A dimer/monomer relationship between the two proteins is suggested, with the dimeric form likely being a heme-binding protein. This possibility was further supported by anionic exchange chromatography and de novo sequencing of tryptic fragments of the protein and sequence comparison, as most of the residues previously implicated in heme binding in 2-cys peroxiredoxin from Rattus norvegicus were conserved in A. macrostachyum. The amount of this protein was modulated by environmental conditions, and increased when salt concentration in the growth medium was higher or lower than the optimal one. [Copyright &y& Elsevier]

Abstract: The effect of different external salt concentrations, from 0mM to 1030mM NaCl, on photosynthetic complexes and chloroplast ultrastructure in the halophyte Arthrocnemum macrostachyum was studied. Photosystem II, but not Photosystem I or cytochrome b6/f, was affected by salt treatment. We found that the PsbQ protein was never expressed, whereas the amounts of PsbP and PsbO were influenced by salt in a complex way. Analyses of Photosystem II intrinsic proteins showed an uneven degradation of subunits with a loss of about 50% of centres in the 0mM NaCl treated sample. Also the shape of chloroplasts, as well as the organization of thylakoid membranes were affected by NaCl concentration, with many grana containing few thylakoids at 1030mM NaCl and thicker grana and numerous swollen thylakoids at 0mM NaCl. The PsbQ protein was found to be depleted also in thylakoids from other halophytes. [Copyright &y& Elsevier]

Abstract: This study dealt with the decomposition and nutrient release from the halophytes Atriplex portulacoides, Arthrocnemum macrostachyum, Limoniastrum monopetalum, and Spartina densiflora, the dominant species in the Castro Marim salt marsh, Portugal. Environmental effects on decomposition were also assessed. The study was carried out for one year using the in situ litterbag technique. S. densiflora showed a lower decomposition rate (k =0.003day−1) than the other study species (k =0.005–0.009). Study species showed similar decomposition patterns, that is, the weight loss mostly occurred during the autumn–winter period (study beginning in November). This indicates that temperature in this period did not hamper the decomposition process. The decomposition rate was positively affected by the initial N concentration (r 2 =0.87, P <0.05) and negatively by the C:N ratio (r 2 =0.86, P <0.05) in decomposing materials. At the end of the study, S. densiflora and L. monopetalum, the species with lower initial N concentrations, retained much higher proportion of initial N (89–109%) than the others (5–14%). Also, S. densiflora with the lowest P concentration retained higher proportion of initial P (48%) than the others (5–20%). Release of K and Mg were also slower from S. densiflora and was associated with their initial low concentration in this species. The lowest Mn release was observed from A. macrostachyum and also in relation to the lowest initial concentration. Our study supports the hypothesis that decomposition patterns of marsh species are mostly associated with differences regarding their morphology and chemical composition. Given the higher resistance of S. densiflora to decomposition, its progressive spreading may result in accumulation of organic detritus overtime in invaded salt marshes. [Copyright &y& Elsevier]

Two saltmarsh species, the native Arthrocnemum macrostachyum (AM) and the invasive Spartina densiflora (SD), were compared in terms of monthly variation of above and belowground biomass, and nutrient (N, P, K, Ca, Mg, Mn) concentrations, over 1 year, in Castro Marim saltmarsh, Portugal. Net aboveground primary productivity was also estimated by two different methods. Above and belowground biomass were higher in SD than in AM and there were distinct monthly variations in the two species. Maximum relative growth rate was observed in the October/January period for SD (4.92 ± 0.36 mg g day) and in April/July for AM (3.37 ± 1.26 mg g day). Whatever the method used, net aboveground primary productivity was higher in SD (2,603 and 2,923 g m yr, respectively by the Smalley and the Wiegert and Evans method) than in AM (692 and 1,012 g m yr, respectively). The turnover rate for aboveground live biomass of AM was half the value of SD (0.8 yr and 1.7 yr, respectively). The N/P ratio in photosynthetic active components and belowground biomass of AM (11 and 13) was higher than in those of SD (7 and 10). Concentrations of K, Ca and Mg in photosynthetic tissues of SD were lower than in AM. Differences observed between study species suggest that S. densiflora has better ability to use resources and to compete with native species. [ABSTRACT FROM AUTHOR]

The Domingo Rubio tidal channel (Palos de la Frontera, Huelva, Spain) is an estuary located in the mouth of the Tinto River. The estuary is affected by different sources of pollution (waters of the Tinto River, contaminated with trace elements from the Iberian Pyrite belt, and effluent from the Huelva chemical industrial area). Soil and the most frequent plant species were collected in 2004 and 2006 at six different locations on the estuary. In general, N-Kjedahl, Total Organic Carbon values, salinity and contamination (total trace elements up to 1,000 mg kg−1 As, 6 mg kg−1 Cd, 2,500 mg kg−1 Cu, 1,900 mg kg−1 Pb and 1,300 mg kg−1 Zn) tended to increase downstream of the tidal channel. Soil biochemical properties were not negatively affected either by the high salinity or by trace element contamination. Despite the high values of the trace elements, analysed plant samples showed that Cu was the only metal that could be a serious risk for the food chain. [ABSTRACT FROM AUTHOR]

The present work studied the germination recovery of Arthrocnemum macrostachyum, Juncus acutus, and Schoenus nigricans seeds after submersion in hypersaline solution of different salt types. Germination recovery of seed lots incubated in 1, 2, 3, 4, or 5% saline solutions of NaCl, MgCl2, MgSO4, and Na2SO4 for 30 d was studied by transferring ungerminated seeds to distilled water. Seed germination of A. macrostachyum was only inhibited at the highest salinity (4% NaCl, 5% MgCl2) but these ungerminated seeds showed a high germination recovery (81% and 83%, respectively) in distilled water. Seed germination of S. nigricans was totally inhibited by salts and only 26% of them germinated in the control treatment. However, the germination recovery of this species could be stimulated by high salt concentrations (germination of ungerminated seeds incubated at 5% Na2SO4 reached 66% in distilled water). Juncus acutus germinated well without salt (95% in the control treatment) but high salt concentrations inhibited them from germination. However, ungerminated seeds were not damaged by salt, showing a high level of recovery (c. 100% in all salt types and concentrations). The chlorides were more inhibitory to germination than sulphates at equivalent concentrations. The germination-related characteristics of J. acutus and S. nigricans mean that both species may be considered halophytes although neither of them can tolerate such high salinity levels as A. macrostachyum, Juncus acutus, and A. macrostachyum produce nondormant seeds, whereas a high proportion of S. nigricans seeds are dormant. These laboratory results are related to the field ecology of the three species. [ABSTRACT FROM AUTHOR]

Abstract: We studied the germination responses of Arthrocnemum macrostachyum, Juncus acutus and Schoenus nigricans to saline stress caused by different salt types. The germination percentage and mean time to germination data were obtained by incubating seeds for 30d in 1, 2, 3, 4 or 5% saline solutions of NaCl, MgCl2, MgSO4 and Na2SO4 at 30/20°C and with a 12h photoperiod. A. macrostachyum was the most tolerant species to salinity during the germination (65% in 2% NaCl). S. nigricans showed the lowest germination (none germinated in salt and only 26% in distilled water). J. acutus showed intermediate behaviour between the two above species, its germination being inhibited by high salt concentrations. The sulphates had less inhibitory effect than the equivalent chloride concentrations. [Copyright &y& Elsevier]