Characterization of a Drought-Induced Betaine Aldehyde Dehydrogenase Gene SgBADH from Suaeda glauca.

Betaine aldehyde dehydrogenases (BADHs) are key enzymes in the biosynthesis of glycine betaine, which is an important organic osmolyte that maintains cell structure and improves plant tolerance to abiotic stresses, especially in halotolerant plants. Improving the drought tolerance of crops will greatly increase their yield. In this study, a novel BADH gene named SgBADH from Suaeda glauca was induced by drought stress or abscisic acid. To explore the biological function of SgBADH, the SgBADH gene was transformed into Arabidopsis. Then, we found SgBADH-overexpressing Arabidopsis seedlings showed enhanced tolerance to drought stress. SgBADH transgenic Arabidopsis seedlings also had longer roots compared with controls under drought stress, while SgBADH-overexpressing Arabidopsis exhibited increased glycine betaine accumulation and decreased malondialdehyde (MDA) under drought stress. Our results suggest that SgBADH might be a positive regulator in plants during the response to drought.

Identification of NAC Transcription Factors in Suaeda glauca and Their Responses to Salt Stress.

NAC (NAM/ATAF1/2/CUC2) transcription factors regulate plant growth and development and stress responses. Because NAC transcription factors are known to play important roles in the regulation of salt tolerance in many plants, we aimed to explore their roles in the halophyte Suaeda glauca. Based on transcriptome sequencing data, we identified 25 NAC transcription factor gene family members. In a phylogenetic tree analysis with Arabidopsis thaliana NAC transcription factors, the SgNACs were divided into 10 groups. The physicochemical properties and conserved domains of the putative proteins, as well as the transcript profiles of their encoding genes, were determined for the 25 SgNAC genes using bioinformatic methods. Most of the S. glauca NAC genes were upregulated to some extent after 24 h of salt stress, suggesting that they play an important role in regulating the salt tolerance of S. glauca. These findings lay the foundation for further research on the functions and mechanisms of the NAC gene family in S. glauca.

Soil bacterial diversity and community structure of Suaeda glauca vegetation in the Hetao Irrigation District, Inner Mongolia, China.

Exploring the bacterial community in the S. glauca rhizosphere was of great value for understanding how this species adapted to the saline-alkali environment and for the rational development and use of saline-alkali soils. In this study, high-throughput sequencing technology was used to investigate the diversity characteristics and distribution patterns of soil bacterial communities in the rhizosphere of S.glauca-dominated communities in the Hetao Irrigation Distract, Inner Mongolia, China. The relationships among bacterial characteristics, soil physicochemical properties and vegetation in four sampling sites were analyzed. The soil bacterial communities in the rhizosphere of S. glauca-dominated communities were mainly composed of 16 phyla (i.e., Proteobacteria, Actinobacteria, Bacteroidetes, Gemmatimonadetes, Chloroflexi, Acidobacteria, Firmicutes, Planctomycetes, Deinococcus-Thermus, Verrucomicrobia, Saccharibacteria, Cyanobacteria, Nitrospirae, JL-ETNP-Z39, Parcubacteria and Chlorobi), and these populations accounted for more than 99% of the total bacterial community. At the genus level, the main bacterial communities comprised Halomonas, Nitriliruptor, Euzebya and Pelagibius, which accounted for 15.70% of the total bacterial community. An alpha diversity analysis indicated that the richness and diversity of rhizosphere soil bacteria differed significantly among the sampling sites, and the bacterial richness and diversity indices of severe saline-alkali land were higher than those of light and moderate saline-alkali land. The principal component analysis (PCA) and linear discriminant analysis effect size (LEfSe) showed significant differences in the species composition of the rhizosphere soil bacterial community among different sampling sites. A correlation analysis showed that the number of bacterial species exhibited the highest correlation with the soil water content (SWC). The richness and evenness indices were significantly correlated with the SWC and SO4 2-, K+ and Mg2+ concentrations. The electrical conductivity (EC), soluble ions (Na+, CO3 2- + HCO3 -, K+, Ca2+, Mg2+, and SO4 2+), SWC and vegetation coverage (VC) were the main drivers affecting the changes in its community structure. The bacterial community in the rhizosphere of S. glauca enhanced the adaptability of S. glauca to saline-alkali environment by participating in the cycling process of nutrient elements, the decomposition of organic matter and the production of plant growth regulating substances. These results provided a theoretical reference for further study on the relationship among rhizosphere soil microorganisms and salt tolerance in halophytes.

Comparative transcriptome analysis reveals the potential mechanism of GA3-induced dormancy release in Suaeda glauca black seeds.

Suaeda glauca Bunge produces dimorphic seeds on the same plant, with brown seeds displaying non-dormant characteristics and black seeds exhibiting intermediate physiological dormancy traits. Previous studies have shown that black seeds have a very low germination rate under natural conditions, but exogenous GA3 effectively enhanced the germination rate of black seeds. However, the physiological and molecular mechanisms underlying the effects of GA3 on S. glauca black seeds are still unclear. In this study, transcriptomic profiles of seeds at different germination stages with and without GA3 treatment were analyzed and compared, and the TTF, H2O2, O2 -, starch, and soluble sugar contents of the corresponding seed samples were determined. The results indicated that exogenous GA3 treatment significantly increased seed vigor, H2O2, and O2 - contents but decreased starch and soluble sugar contents of S. glauca black seeds during seed dormancy release. RNA-seq results showed that a total of 1136 DEGs were identified in three comparison groups and were involved mainly in plant hormone signal transduction, diterpenoid biosynthesis, flavonoid biosynthesis, phenylpropanoid biosynthesis, and carbohydrate metabolism pathway. Among them, the DEGs related to diterpenoid biosynthesis (SgGA3ox1, SgKAO and SgGA2ox8) and ABA signal transduction (SgPP2Cs) could play important roles during seed dormancy release. Most genes involved in phenylpropanoid biosynthesis were activated under GA3 treatment conditions, especially many SgPER genes encoding peroxidase. In addition, exogenous GA3 treatment also significantly enhanced the expression of genes involved in flavonoid synthesis, which might be beneficial to seed dormancy release. In accordance with the decline in starch and soluble sugar contents, 15 genes involved in carbohydrate metabolism were significantly up-regulated during GA3-induced dormancy release, such as SgBAM, SgHXK2, and SgAGLU, etc. In a word, exogenous GA3 effectively increased the germination rate and seed vigor of S. glauca black seeds by mediating the metabolic process or signal transduction of plant hormones, phenylpropanoid and flavonoid biosynthesis, and carbohydrate metabolism processes. Our results provide novel insights into the transcriptional regulation mechanism of exogenous GA3 on the dormancy release of S. glauca black seeds. The candidate genes identified in this study may be further studied and used to enrich our knowledge of seed dormancy and germination.

Chemical Constituents of Halophyte Suaeda glauca and Their Therapeutic Potential for Hair Loss.

Suaeda glauca, a halophyte in the Amaranthaceae family, exhibits remarkable resilience to high salt and alkali stresses despite the absence of salt glands or vesicles in its leaves. While there is growing pharmacological interest in S. glauca, research on its secondary metabolites remains limited. In this study, chemical constituents of the aerial parts of S. glauca were identified using 1D- and 2D-NMR experiments, and its biological activity concerning hair loss was newly reported. Eight compounds, including alkaloids (1~3), flavonoids (4~6), and phenolics (7 and 8), were isolated. The compounds, except the flavonoids, were isolated for the first time from S. glauca. In the HPLC chromatogram, quercetin-3-O-ß-d-glucoside, kaempferol-3-O-ß-d-glucoside, and kaempferol were identified as major constituents in the extract of S. glauca. Additionally, the therapeutic potential of the extract of S. glauca and the isolated compounds 1~8 on the expressions of VEGF and IGF-1, as well as the regulation of Wnt/ß-catenin signaling, were evaluated in human follicle dermal papilla cells (HFDPCs) and human umbilical vein endothelial cells (HUVECs). Among the eight compounds, compound 4 was the most potent in terms of increasing the expression of VEGF and IGF-1 and the regulation of Wnt/ß-catenin. These findings suggest that S. glauca extract and its compounds are potential new candidates for preventing or treating hair loss.

Decoupling of nutrient stoichiometry in Suaeda glauca (Bunge) senesced leaves under salt treatment.

The stoichiometry of senesced leaves is pivotal in nutrient cycling and can be significantly influenced by soil salinization, a rising global issue threatening the functionality of ecosystems. However, the impacts of soil salinization on senesced leaf stoichiometry are not fully understood. In this study, we conducted a pot experiment with varying soil salt concentrations to examine their influence on the concentrations and stoichiometric ratios of nitrogen (N), phosphorus (P), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), and zinc (Zn) in the senesced leaves of Suaeda glauca (Bunge). Compared to the control group, salt treatments significantly enhanced Na concentration while diminishing the concentrations of K, Ca, Mg, Zn, N, and P. Interestingly, as salinity levels escalated, N concentration maintained stability, whereas P concentration exhibited an increasing trend. Moreover, K, Ca, and Mg significantly declined as salt levels rose. Salt treatments brought about significant changes in stoichiometric ratios, with the N:P, K:Na, N:Na, N:Mg, and Ca : Mg ratios dropping and the N:Ca and N:K ratios rising, illustrating the varying nutrient coupling cycles under different salt conditions. These findings shed light on the plasticity of stoichiometric traits in S. glauca senesced leaves in response to soil salinization shifts, which could potentially offer insights into nutrient cycling reactions to soil salinization.

Suaeda glauca Attenuates Liver Fibrosis in Mice by Inhibiting TGFß1-Smad2/3 Signaling in Hepatic Stellate Cells.

Chronic liver injury due to various hepatotoxic stimuli commonly leads to fibrosis, which is a crucial factor contributing to liver disease-related mortality. Despite the potential benefits of Suaeda glauca (S. glauca) as a natural product, its biological and therapeutic effects are barely known. This study investigated the effects of S. glauca extract (SGE), obtained from a smart farming system utilizing LED lamps, on the activation of hepatic stellate cells (HSCs) and the development of liver fibrosis. C57BL/6 mice received oral administration of either vehicle or SGE (30 or 100 mg/kg) during CCl4 treatment for 6 weeks. The supplementation of SGE significantly reduced liver fibrosis induced by CCl4 in mice as evidenced by histological changes and a decrease in collagen accumulation. SGE treatment also led to a reduction in markers of HSC activation and inflammation as well as an improvement in blood biochemical parameters. Furthermore, SGE administration diminished fibrotic responses following acute liver injury. Mechanistically, SGE treatment prevented HSC activation and inhibited the phosphorylation and nuclear translocation of Smad2/3, which are induced by transforming growth factor (TGF)-ß1 in HSCs. Our findings indicate that SGE exhibits anti-fibrotic effects by inhibiting TGFß1-Smad2/3 signaling in HSCs.

Undescribed diphenyl ethers betaethrins A-I from a desert plant endophytic strain of the fungus Phoma betae A.B. Frank (Didymellaceae).

Ten diphenyl ethers (DPEs), including nine undescribed analogs named betaethrins A-I, were isolated from the desert plant endophytic fungus Phoma betae A.B. Frank (Didymellaceae). Their structures were determined mainly by NMR, HR-ESI-MS spectral and X-ray diffraction experiments. Betaethrins D-I possessed different fatty acid chains connected with the B-ring, which was the first report in all DPEs. The shielding effect of the B-ring on H-6 (A-ring) in methyl barceloneate, betaethrin A and betaethrins D-F (asterric acid analogs) was first observed and analyzed, which could differentiate the 1H-NMR chemical shift values of H-4/H-6 without the assistance of 3-OH. An empirical rule was then suggested: the steric hindrance between the A- and B-rings in asterric acid analogs might prevent these two aromatic rings from rotating freely, which led to the 1H-NMR chemical shift value of H-6 being in the high field zone due to the shielding effect of the B-ring on H-6. Based on the empirical rule, the chemical shift values of the A-ring in methyl barceloneate were revised. The possible biosynthesis of these isolates was postulated. Betaethrin H showed moderate cytotoxicity against MCF-7 and HepG2 cancer cell lines. Betaethrins A-F, H and I displayed strong antioxidant activities. These results further implied that endophytic fungi from unique environments, such as desert plants, with few chemical studies are an important resource of undescribed and bioactive metabolites.

Synergetic effects of microbial-phytoremediation reshape microbial communities and improve degradation of petroleum contaminants.

Microbial-phytoremediation is an effective bioremediation technology that introduces petroleum-degrading bacteria and oil-tolerant plants into oil-contaminated soils in order to achieve effective degradation of total petroleum hydrocarbons (TPH). In this work, natural attenuation (NA), microbial remediation (MR, using Acinetobacter sp. Tust-DM21), phytoremediation (PR, using Suaeda glauca), and microbial-phytoremediation (MPR, using both species) were utilized to degrade petroleum hydrocarbons. We evaluated four different biological treatments, assessing TPH degradation rates, soil enzyme activities, and the structure of microbial community in the petroleum-contaminated soil. This finding revealed that the roots of Suaeda glauca adsorbed small amounts of polycyclic aromatic hydrocarbons, causing the structure of soil microbiota community to reshape. The abundance of petroleum-degrading bacteria and plant growth-promoting rhizobacteria (PGPR) has increased, as has microbial diversity. According to correlation research, these genera increased soil enzyme activity, boosted the number of degradation-functional genes in the petroleum hydrocarbon degradation pathway, and accelerated the dissipation and degradation of TPH in petroleum-contaminated soil. This evidence contributes to a better understanding of the mechanisms involved in the combined microbial-phytoremediation strategies for contaminated soil, specifically the interaction between microflora and plants in co-remediation and the effects on the structural reshaping of rhizosphere microbial communities.

Experimental evidence from Suaeda glauca explains why the species is not naturally distributed in non-saline soils.

Euhalophytes are not naturally distributed in non-saline areas. However, the reason for this is unclear. Seed germination, seedling emergence and plant tolerance to salt were evaluated in the euhalophyte Suaeda glauca. One population occurs in saline soils (SS), and another has been cultivated in non-saline soils (NSS) for more than 20 years. A total of 500 mM NaCl had a greater adverse effect on seed germination and seedling emergence of brown seeds in S. glauca from NSS compared with those from SS. The seedlings grown from brown seeds collected from NSS were uniform and dwarf, but this was not the case for the seedlings from SS. The salt tolerance of seedlings from NSS did not significantly differ from those from SS, as judged by such factors as the shoot dry weight and contents of leaf Na+ and K+. The concentrations of phytohormones, such as abscisic acid, methyl jasmonate, gibberellin 3 and 4, zeatin riboside, brassinolide, indole acetic acid, and indole-3-propionic acid, in the leaves of seedlings from NSS were generally lower than those from SS under different concentrations of NaCl. In conclusion, salts are not strictly required for the growth of S. glauca. The reason why typical euhalophytes, such as S. glauca, are not found in non-saline areas is probably because the seedlings grown in NSS become dwarf and uniform, thus, weakening their ability to compete with glycophytes in non-saline habitats.

Profiles of Bacillus spp. Isolated from the Rhizosphere of Suaeda glauca and Their Potential to Promote Plant Growth and Suppress Fungal Phytopathogens.

Members of the genus Bacillus are known to play an important role in promoting plant growth and protecting plants against phytopathogenic microorganisms. In this study, 21 isolates of Bacillus spp. were obtained from the root micro-ecosystem of Suaeda glauca. Analysis of the 16S rRNA genes indicated that the isolates belong to the species Bacillus amyloliquefaciens, Bacillus velezensis, Bacillus subtilis, Bacillus pumilus, Bacillus aryabhattai and Brevibacterium frigoritolerans. One of the interesting findings of this study is that the four strains B1, B5, B16 and B21 are dominant in rhizosphere soil. Based on gyrA, gyrB, and rpoB gene analyses, B1, B5, and B21 were identified as B. amyloliquefaciens and B16 was identified as B. velezensis. Estimation of antifungal activity showed that the isolate B1 had a significant inhibitory effect on Fusarium verticillioides, B5 and B16 on Colletotrichum capsici (syd.) Butl, and B21 on Rhizoctonia cerealis van der Hoeven. The four strains grew well in medium with 1-10% NaCl, a pH value of 5-8, and promoted the growth of Arabidopsis thaliana. Our results indicate that these strains may be promising agents for the biocontrol and promotion of plant growth and further study of the relevant bacteria will provide a useful reference for the development of microbial resources.

Insights into the endophytic bacterial community comparison and their potential role in the dimorphic seeds of halophyte Suaeda glauca.

BACKGROUND: Seed dimorphism has been thought to be a bet-hedging strategy that helps plants survive in the disturbed environment and has been widely studied for its ecological adaptation mechanism. Many studies showed that seed-associated microorganisms play an important role in enhancing plant fitness, but information regarding endophytic bacteria associated with dimorphic seeds is limited. This study explores the influence of seed coat structure and seed phytochemical properties on the community composition and diversity of endophytic bacteria of dimorphic seeds of Suaeda glauca. In this study, we used 16S rRNA high-throughput gene sequencing method to compare the community composition and bacterial diversity between brown and black seeds of Suaeda glauca. RESULTS: A significant difference was observed in seed coat structure and phytochemical properties between brown and black seeds of S. glauca. Total 9 phyla, 13 classes, 31 orders, 53 families, 102 genera were identified in the dimorphic seeds. The dominant phyla were Proteobacteria, Firmicutes, and Actinobacteria. The results showed that seed dimorphism had little impact on the diversity and richness of endophytic bacterial communities but significantly differs in the relative abundance of the bacterial community between brown and black seeds. At the phylum level, Actinobacteria tend to be enriched significantly in brown seeds. At the genus level, Rhodococcus, Ralstonia, Pelomonas and Bradyrhizobium tend to be enriched significantly in brown seeds, while Marinilactibacillus was mainly found in black seeds. Besides, brown seeds harbored a large number of bacteria with plant-growth-promoting traits, whereas black seeds presented bacteria with enzyme activities (i.e., pectinase, cellulolytic and xylanolytic activities). CONCLUSION: The endophytic bacterial community compositions were significantly different between dimorphic seeds of Suaeda glauca, and play an important role in the ecological adaptation of dimorphic seeds by performing different biological function roles. The endophytic bacterial communities of the dimorphic seeds may be influenced mainly by the seed coat structureand partly by the seed phytochemical characteristics. These findings provide valuable information for better understanding of the ecological adaptation strategy of dimorphic seeds in the disturbed environment.

Assembly and comparative analysis of the complete mitochondrial genome of Suaeda glauca.

BACKGROUND: Suaeda glauca (S. glauca) is a halophyte widely distributed in saline and sandy beaches, with strong saline-alkali tolerance. It is also admired as a landscape plant with high development prospects and scientific research value. The S. glauca chloroplast (cp) genome has recently been reported; however, the mitochondria (mt) genome is still unexplored. RESULTS: The mt genome of S. glauca were assembled based on the reads from Pacbio and Illumina sequencing platforms. The circular mt genome of S. glauca has a length of 474,330 bp. The base composition of the S. glauca mt genome showed A (28.00%), T (27.93%), C (21.62%), and G (22.45%). S. glauca mt genome contains 61 genes, including 27 protein-coding genes, 29 tRNA genes, and 5 rRNA genes. The sequence repeats, RNA editing, and gene migration from cp to mt were observed in S. glauca mt genome. Phylogenetic analysis based on the mt genomes of S. glauca and other 28 taxa reflects an exact evolutionary and taxonomic status of S. glauca. Furthermore, the investigation on mt genome characteristics, including genome size, GC contents, genome organization, and gene repeats of S. gulaca genome, was investigated compared to other land plants, indicating the variation of the mt genome in plants. However, the subsequently Ka/Ks analysis revealed that most of the protein-coding genes in mt genome had undergone negative selections, reflecting the importance of those genes in the mt genomes. CONCLUSIONS: In this study, we reported the mt genome assembly and annotation of a halophytic model plant S. glauca. The subsequent analysis provided us a comprehensive understanding of the S. glauca mt genome, which might facilitate the research on the salt-tolerant plant species.

Immobilization of Lead and Cadmium in Soil Using Biochars Derived from Pig Manure and Suaeda glauca.

Biochar was for the first time produced from Suaeda glauca. The immobilization of Pb and Cd by this biochar and pig manure biochar was examined in two types of soils by diethylene triamine pentaacetic acid (DTPA) extraction. Addition of biochars decreased DTPA extractable Pb and Cd in Fluvo-aquic soil with reduction rates being 11.3%-48.4% and 0.74%-64.9% compared with the control treatment. The pig manure biochar favored the immobilization of Pb and S. glauca biochar favored the immobilization of Cd. Biochars can effectively immobilize heavy metals in Fluvo-aquic soil. However, the addition of biochars increased extractable Pb and Cd in red soil, with pig manure biochars showing greater rates. This is ascribed to that the competition effects of ions released from biochar enhanced the moving of heavy metals from iron and manganese oxides bound form to organic matter bound form, and hence enhanced the mobility and bioavailability of heavy metals.

The size and distribution of tidal creeks affects salt marsh restoration.

Salt marshes are changeable and important ecosystems that currently face various threats, including global climate change and human activities. The influence of these factors can result in the degradation of salt marshes. Tidal creeks, which are an important source of nutrients and other substances for salt marsh vegetation, play an important role in the health of salt marshes. In this study, the morphological characteristics of tidal creeks and the characteristics of two typical plants, Suaeda glauca (SG) and Phragmites communis (PC), in the Yellow River Delta, China were investigated to determine the effect of tidal creeks on these plants. Aerial photography and field measurements of tidal creeks were carried out from May to July 2018 in the study area. At the same time, nine line-intercepts were set in the vertical direction of tidal creeks to investigate plants. The results showed that different grades of tidal creek exerted no significant influence on the growth of either S. glauca or P. communis. However, unlike grade, the size of a creek and the distance from it had marked effects on these plants. The cross-sectional area of a tidal creek had a significant positive impact on the density of S. glauca (r = 0.39, p = 0.02). For P. communis, the depth of a tidal creek had a strong correlation with this species' density (r = 0.51, p = 0.04) and height (r = 0.63, p = 0.01). Meanwhile, there was a negative relationship between the distance from tidal creeks and the height of S. glauca (r = -0.52, p = 0.02). Conversely, the height (r = 0 0.90, p = 0.00) and density (r = 0.62, p = 0.01) of P. communis were positively affected by its vertical distance from tidal creeks. We found that the subtidal zone near a tidal creek was more conducive to the recovery and growth of S. glauca, and that areas further away from a tidal creek, located in the intertidal and subtidal zones, were more conducive to the recovery and growth of P. communis. The parameters associated with tidal creeks in the subtidal zone (cross sectional area 4.55 m2, distance 0-10 m) were beneficial for the growth of S. glauca. For P. communis, relevant features in the intertidal and subtidal zones (depth 0.40-0.45 m, distance 20-60 m) are useful. Our results suggest that attention should be paid to the effects of size and distribution of tidal creeks during the process of salt marsh restoration. This work also provides practical guidance for the restoration of native salt marshes in China.

The complete chloroplast genome of an annual halophyte herb, Suaeda glauca (Amaranthaceae).

The complete chloroplast genome (plastome) of Suaeda glauca, an annual halophytic herb, was determined in this study. The plastome was 149,807 bp in size, containing a large single-copy region (82,162 bp), a small single-copy region (18,191 bp), and two inverted repeats regions (24,727 bp). The overall GC content of this plastome was 36.5%. In total, 113 unique genes, including 79 protein-coding genes (PCGs), 30 tRNAs and 4 rRNAs, were annotated. Phylogenomic analysis showed that S. glauca was sister to other Suaeda species.

Effect of combined waterlogging and salinity stresses on euhalophyte Suaeda glauca.

Salinity and waterlogging are abiotic stresses that have a significant impact on agricultural production and ecosystem conservation. The response of euhalophyte Suaeda glauca to waterlogging and salinity stresses was investigated. The results revealed that waterlogging markedly decreased seedling emergence. Compared to drained conditions, waterlogging inhibited the shoot dry weight, net photosynthetic rate, stomatal conductance, maximal efficiency of PSII photochemistry and chlorophyll content at salinity. Salinity decreased these values in both waterlogged and drained conditions, while the opposite trend was found in intercellular CO2 concentrations. Waterlogging increased Na+, Cl-, O2-, H2O2 and MDA content in the leaves compared with those in drained conditions, but this was not the case for K+ content and SOD and APX activity. Salinity increased these values except that salinity decreased K+ content in both waterlogged and drained conditions. In conclusion, S. glauca is not tolerant to combined waterlogging and salinity stresses during both seedling emergence and seedling growth stages, and this trait may limit the distribution of the species in lowland saline areas.

Stoichiometric variation of halophytes in response to changes in soil salinity.

Variation in soil salt may change the stoichiometry of a halophyte by altering plant ecophysiology, and exert different influences on various plant organs, which has potentially important consequences for the nutrition of consumers as well as nutrient cycling in a saline ecosystem. Using a greenhouse pot experiment, we investigated the effect of salinity variability on the growth and stoichiometry of different organs of Suaeda glauca and Salicornia europaea - two dominant species of important ecological and economic value in the saline ecosystem. Our results showed that appropriate salt stimulated the growth of both species during the vigorous growth period, while high salt suppressed growth. Na significantly increased with increased salt in the culture, whereas concentrations of other measured elements and K:Na ratio for both species significantly decreased at low salt treatments, and became more gradual under higher salt conditions. Furthermore, with the change of salt in culture, variations in leaf (degenerated leaf for S. europaea, considered as young stem) stoichiometry, except N:P ratio, were large and less in stems (old stems for S. europaea) than in roots, reflecting physiological and biochemical reactions in the leaf in response to salt stress, supported by sharp changes in trends. These results suggest that appropriate saline conditions can enhance biological C fixation of halophytes; however, increasing salt could affect consumer health and decrease cycling of other nutrients in saline ecosystems.

Meat quality, fatty acid composition of tissue and gastrointestinal content, and antioxidant status of lamb fed seed of a halophyte (Suaeda glauca).

Twenty-four Merino lambs were randomly assigned to four treatments: control diet (CT) consisting of 300g concentrates with ad libitum Leymus chinensis hay; C with 150g (T150), 300g (T300) and 450g (T450) Suaeda glauca seed, respectively. Meat quality, fatty acid composition of meat and lipid tissue and antioxidant status of lamb were evaluated. Inclusion of S. glauca seeds significantly increased selenium (Se) concentrations of muscle. The proportions of C18:1 trans-11 in muscle, C18:2 n-6, PUFA, n-6 series fatty acids, and the ratios of P:S in rumen contents, as well as the ratios of n-6:n-3 in adipose tissue, rumen and duodenum content have been significantly (P<0.05) improved with supplementation of S. glauca seeds to lamb diets. No significant effect was found on antioxidant status. The results suggest that S. glauca seed supplementation in lamb diets may change fatty acid composition in tissues and content of digestive tract.