Arthrocnemum Macrostachyum Research Articles

Ethanol/water extracts from halophyte species Arthrocnemum macrostachyum and Tetraena qatarensis

Microwave-assisted extraction using various concentrations of ethanol in water (25%, 50%, 75% v/v) was carried out using biomass from halophytes; Arthrocnemum macrostachyum and Tetraena qatarensis....

In vitro and in silico perspectives on biological and phytochemical profile of three halophyte species—A source of innovative phytopharmaceuticals from nature

BackgroundHalophytes are considered as valuable sources of traditional drugs in different countries. PurposeThe present study aimed to evaluate biological and chemical fingerprints of three halophytes (Arthrocnemum macrostachyum (Moric.) C, Koch, Halimione portulacoides (L.) Aellen and Salicornia europaea L.). Materials and methodsThe antioxidant and enzymatic inhibitory potential (acetylcholinesterase, butyrylcholinesterase, α-amylase, α-glucosidase, and tyrosinase) were assessed. The total phenolic, flavonoid contents, and the chemical profiles were appraised using the ultra-high performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Molecular docking was conducted to provide additional insights of molecular interactions of the enzymes/phytochemicals. ResultsEthyl acetate extract was the most efficient extract, with A. macrostachyum being the most potent towards DPPH and ABTS radicals and phosphomolybdenum assay. Ethyl acetate extract of A. macrostachyum was also the best reducing agent (CUPRAC and FRAP assays). Methanol and ethyl acetate extract of A. macrostachyum, H. portulacoides, and S. europaea showed significant enzyme inhibition potential. Ethyl acetate extract of A. macrostachyum showed the highest total phenolic (29.54 ± 0.78 mgGAEs/g extract) while the ethyl acetate extract of S. europaea was more abundant in flavonoids (18.26 ± 0.11 mgREs/g extract). Phytochemical profiling allowed the identification of several components in the methanolic extracts (16 in A. macrostachyum, 14 in H. portulacoides, and 11 in S. europaea), with quinic acid, p-coumaric acid, and rhamnetin being most abundant. Docking studies revealed that the above compounds showed scores for the enzymes tested. ConclusionThe three halophytes studies could be considered as potential sources of biologically-active compounds for novel phytopharmaceuticals development.

Kocuria salina sp. nov., an actinobacterium isolated from the rhizosphere of the halophyte Arthrocnemum macrostachyum and emended description of Kocuria turfanensis.

A novel, non-motile coccoid, Gram-positive and non-endospore forming bacterium, designated Hv14bT, was isolated from the rhizosphere of the halophyte Arthrocnemum macrostachyum. It was observed to be catalase positive and oxidase negative and able to hydrolyse starch. MK-8(H2) was identified as the dominant menaquinone and the major cellular fatty acids were anteiso-C15 : 0 and iso-C15 : 0. The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol and an unidentified glycolipid. The 16S rRNA genes showed the highest 16S rRNA sequence identity with K. polaris DSM 14382T, K. rosea DSM 20447T and K. turfanensis DSM 22143T. Based on the phenotypic and molecular features and DNA-DNA hybridization data, it is concluded that strain Hv14bT is proposed to represent a novel species in the genus Kocuria, Kocuria salina sp. nov., with the type strain Hv14bT=DSM 28714T=CECT 9229T.

Vibrio palustris sp. nov. and Vibrio spartinae sp. nov., two novel members of the Gazogenes clade, isolated from salt-marsh plants (Arthrocnemum macrostachyum and Spartina maritima).

Two bacterial strains, EAod9T and SMJ21T, isolated from salt-marsh plants, were determined to be related to species of the genus Vibriofrom from 16S rRNA sequence comparisons. Their closest phylogenetic relatives are members of the Gazogenes clade, Vibrio mangrovi and Vibrio rhizosphaerae , which show the greatest similarity to the SMJ21TrRNA sequence (97.3 and 97.1 %, respectively), while EAod9T had less than 97.0 % similarity to any other species of the genus Vibrio. Both strains share the basic characteristics of the genus Vibrio, as they are Gram-stain negative, motile, slightly halophilic, facultatively anaerobic bacteria. In addition, they are oxidase-negative and unable to grow on TCBS Agar; they grow between 15 to 26 °C, pH 6 to 8 and in up to 10 % (w/v) total salinity. They produce indol, are positive in the Voges-Proskauer test and are negative for arginine dihydrolase, lysine and ornithine decarboxylases. Strain SMJ21T is aerogenic and red-pigmented, due to prodigiosin production, while strain EAod9T ferments glucose without gas and is not pigmented. The major cellular fatty acids of both novel strains were C16 : 1ω7c/C16 : 1ω6c and C16 : 0. WGSobtained for both strains, along with the other five members of the clade, allowed the determination of ANI indexes and in silico estimations of DDH values, which confirmed that the two strains represent two novel species of the genus Vibrio: Vibriopalustris sp. nov. (with EAod9T=CECT 9027T=LMG 29724T as the proposed type strain) and Vibrio spartinae sp. nov. (with SMJ21T=CECT 9026T=LMG 29723T as the proposed type strain).

Haloflatagen. nov. — A New Genus from Salt Marshes in Socotra Island (Hemiptera: Fulgoromorpha: Flatidae)

A new monotypic genus of flatid planthoppers (Hemiptera: Fulgoromorpha: Flatidae) is described from Socotra island (Yemen): Haloflata gen. nov. for H. arthrocnemi sp. nov. (type species). Habitus, male and female external and internal genital structures of the new species are illustrated and compared with similar taxa. The new species was found in association with Arthrocnemum macrostachyum (Amaranthaceae) in coastal saltmarshes in western Socotra.

Seed viability of five wild Saudi Arabian species by germination and X-ray tests.

Our objective was to evaluate the usefulness of the germination vs. the X-ray test in determining the initial viability of seeds of five wild species (Moringa peregrina, Abrus precatorius, Arthrocnemum macrostachyum, Acacia ehrenbergiana and Acacia tortilis) from Saudi Arabia. Usually several days were required to determine the viability of all five species via germination tests. However, X-ray test will give immediate results on filled/viable seeds. Seeds of all species, except Acacia ehrenbergiana and Acacia tortilis showed high viability in both germination (96–72% at 25/15 °C, 94–70% at 35/25 °C) and X-ray (100–80%) test. Furthermore, there was a general agreement between the germination (19%, 14% at 25/15 °C and 17% and 12% at 35/25 °C) and X-ray (8%, 4%) tests in which seed viability of Acacia ehrenbergiana and Acacia tortilis was very low due to insect damaged embryo as shown in X-ray analysis. Seeds of Abruspreca torius have physical dormancy, which was broken by scarification in concentrated sulfuric acid (10 min), and they exhibited high viability in both the germination (83% at 25/15 °C and 81% at 35/25 °C) and X-ray (96%) tests. Most of the nongerminated seeds of the five species except those of Acacia ehrenbergiana and Acacia tortilis, were alive as judged by the tetrazolium test (TZ). Thus, for the five species examined, the X-ray test was proved to be a good and rapid predictor of seed viability.

Germination syndromes in response to salinity of Chenopodiaceae halophytes along the intertidal gradient

Germination is a crucial stage in the life cycle of plants and salinity is one of the most important factors conditioning it in salt marshes. This work analyses the effects of salinity on the germination of eight dominant Chenopodiaceae species inhabiting the intertidal gradient in the Gulf of Cádiz. Seeds were collected from Sarcocornia perennis, Atriplex portulacoides, Sarcocornia fruticosa, Salicornia ramosissima, Arthrocnemum macrostachyum, Suaeda vera, Salsola vermiculata and Sarcocornia alpini. They were placed in Petri dishes at 0.0, 0.1, 0.2, 0.3, 0.6 and 0.9M NaCl and germination was recorded during 30days. Ungerminated seeds were transferred to distilled water and germination recovery was recorded. High salinities inhibited germination, although tended to accelerate it in the recovery assays. Beyond these common responses, the studied halophytes showed four germination syndromes: 1) high germination at low-medium salinities and reduced germination after high salinity exposure; 2) no germination at hypersalinity and high recovery germination in fresh water; 3) increased and rapid germination after salinity exposure; and 4) germinating along a wide salinity range. The two species colonising the ecotone between marshes and dunes, Suaeda vera and Salsola vermiculata, shared Syndrome 2. Syndromes 3 and 4 were shared by species colonising different habitats and Syndrome 1 by A. macrostachyum, and fruits of A. portulacoides without bracteoles and S. vermiculata without calyx. The germination of species from high marshes was characterized by marked responses to salinity changes, whereas the germination of low marsh species was based on low sensitivity to salinity fluctuations.

Halophytes: Gourmet food with nutritional health benefits?

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 (5.20–13.2g/100gdw) 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 (64.1–109mg/gdw), and S. ramosissima is an excellent source of manganese (204μg/gdw). 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 (20.5–49.2mgGAE/g). A. macrostachyum had the highest RSA (IC50-DPPH=0.84mg/mL; IC50-NO=0.60mg/mL), and iron reducing potential (IC50=0.84mg/mL) along with high levels of α- and γ-tocopherol (8.74 and 4.71mg/100gdw, respectively).

Phylogeny, biogeography, systematics and taxonomy of Salicornioideae (Amaranthaceae/Chenopodiaceae) – A cosmopolitan, highly specialized hygrohalophyte lineage dating back to the Oligocene

AbstractSalicornioideae (Amaranthaceae / Chenopodiaceae) comprise 11 genera and ca. 100 species of succulent halophytes distributed worldwide in coastal and inland saline habitats. Most species have peculiar articulated, seemingly leafless stems and spike‐like sessile thyrses with highly reduced flowers hidden by fleshy bracts. We analysed sequence data of four markers (ETS, ITS, atpB‐rbcL, matK‐trnK) from 57 species, 9 subspecies, 1 variety and 2 hybrids representing all curently accepted genera using maximum likelihood, Bayesian analysis, fossil‐calibrated molecular dating and ancestral area analysis. All molecular markers gave similar phylogenetic signals. Salicornioideae probably originated in Eurasia during the late Eocene–early Oligocene. The divergence of the early main clades took place in the middle Oligocene with the separation of Allenrolfea /Heterostachys, Halocnemum /Halopeplis /Halostachys /Kalidium and Arthrocnemum /Microcnemum /Tecticornia /Salicornia/ Sarcocornia lineages. The latter lineage diversified most and comprises ¾ of the species of the subfamily. The Arthrocnemum macrostachyum /Microcnemum lineage diverged at the turn of the Oligocene/Miocene – while the Arthrocnemum subterminale, Tecticornia and Salicornia /Sarcocornia lineages were all present by the middle Miocene. Long‐distance dispersal has taken place several times to the Americas (Allenrolfea /Heterostachys, Arthrocnemum subterminale, Salicornia /Sarcocornia), South Africa (Halopeplis, Salicornia /Sarcocornia) and Australia (Tecticornia, Salicornia /Sarcocornia). Most currently accepted genera were resolved as monophyletic. However, Sarcocornia is paraphyletic in relation to Salicornia, and Arthrocnemum proved to be polyphyletic. In addition, the name Arthrocnemum is a nomenclatural synonym of Salicornia. As a consequence, we propose the merging of Sarcocornia under Salicornia and provide 19 new nomenclatural combinations and one replacement name. For Salicornia (incl. Sarcocornia) we propose a new infrageneric classification to accommodate the four phylogenetically and geographically well‐supported sublineages of the genus. We also propose abandoning the name Arthrocnemum in its current use, and describe two new genera, Arthrocaulon (Eurasia, Africa) and Arthroceras (North America), and provide three new nomenclatural combinations.

Volatile fatty acids and methane production from browse species of Algerian arid and semi-arid areas

ABSTRACTThe objective of the study was to determine the in vitro rumen fermentation end-products of 10 browse species. Serum bottles containing 500 mg of substrate, 10 ml of sheep rumen fluid and 40 ml of buffered medium were incubated for 24 h. After incubation, pH, methane and volatile fatty acid (VFA) productions were recorded. There were differences among feedstuffs (p < .05) in pH and VFA production. Astragalus gombo resulted in the highest and Stipa tenacissima in the lowest VFA production. Gas production was highest for Medicago sativa and lowest for S. tenacissima. Methane production (ml/g DM incubated) varied greatly. The lowest methane production was for S. tenacissima and Arthrocnemum macrostachyum (11.4 and 11.5 ml/g DM, respectively) and the highest for M. sativa and A. gombo (25.8 and 22.7 ml/g DM, respectively). The differences among species shrank when methane was expressed per ml of total gas produced or per mol of VFA produced. This indicates that a lower methane production would be due to a low fermentability of the substrate incubated, rather than to a specific inhibitory effect on methanogenesis. Hence, the 10 browse species studied herein would show little potential for mitigating ruminal methane production.

Low diversity and abundance of root endophytes prevail throughout the life cycle of an annual halophyte

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.

Assessing the role of endophytic bacteria in the halophyte Arthrocnemum macrostachyum salt tolerance.

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.

Labrenzia salina sp. nov., isolated from the rhizosphere of the halophyte Arthrocnemum macrostachyum.

A novel, halophilic, motile, rod-shaped, Gram-staining-negative and non-endospore forming bacterium, designated Cs25T, was isolated from the rhizosphere of the halophyte Arthrocnemum macrostachyum growing in a tidal flat. Strain Cs25T was observed to be catalase-negative and oxidase-positive, and to hydrolyse hypoxanthine. Growth occurred from 15 to 40 °C, at pH 7.0-10.0 and with 1-11 % (w/v) NaCl. Q-10 was identified as the dominant ubiquinone, and the major cellular fatty acids were C18 : 1ω7c, 11-methyl C18 : 1ω7c, C20 : 1ω7c and C18 : 0. The polar lipids comprised phosphatidylmonomethylethanolamine, phosphatidylcholine, sulphoquinovosyldiacylglyceride, diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The 16S rRNA gene showed 99.19, 98.6 and 98.59 % sequence identity with Labrenzia alba DSM 18320T, L. aggregata DSM 13394T and L. marina DSM 17023T, respectively. Based on the phenotypic and molecular features and DNA-DNA hybridization data, it is concluded that strain Cs25T represents a novel species for which the name Labrenzia salinasp. nov. is proposed. The type strain is Cs25T (=DSM 29163T=CECT 8816T).

Endophytic microbial diversity of the halophyte Arthrocnemum macrostachyum across plant compartments.

In this study, the microbial community structures of the endosphere of the halophyte Arthrocnemum macrostachyum were evaluated from two locations in Mallorca, Spain, focusing on three plant compartments (roots, green and red stems) compared to the rhizospheric soil where the plants grew. The physicochemical parameters of the rhizospheric soils differed between locations, and the soils were characterized by different microbial community structures. Accordingly, the endophytic community composition, mainly composed of putatively halophilic organisms, was highly influenced by the rhizospheric soil microbiota, as revealed by the co-occurrence of the major endophytic taxa in the endosphere and the rizospheric soils. Moreover, the reduction of diversity from the endorhizosphere towards the red leaves may support the fact that part of colonization of the plant by bacteria could have an origin in the rhizospheric soils through the roots and subsequent migration to the aerial parts of the plant. Finally, there were certain relevant ubiquitous taxa, such as Chromohalobacter canadensis, Rudaea cellulosilytica (never reported before as endophytic), Psychrobacter sp., Bradyrhizobium sp. and Halomonas sp., that, due their moderate halophilic nature, seemed to find an optimal environment inside the plants. Some of these relevant endophytes were not always detectable in their respective soils, and were probably part of the soils' rare biosphere, which would gain preponderance in a favorable endophytic environment.

Isolation of plant-growth-promoting and metal-resistant cultivable bacteria from Arthrocnemum macrostachyum in the Odiel marshes with potential use in phytoremediation

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.

A new species of Arthrocnemum (Salicornioideae: Chenopodiaceae-Amaranthaceae) from West Africa, with a revised characterization of the genus

A new species Arthrocnemum franzii Sukhor. is described from the Republic of Cape Verde (Sal, Maio and Boa Vista islands). The species is recognized as distinct from Arthrocnemum macrostachyum (Moric.) K.Koch based on differences in the perianth shape, length of the anthers and style, and seed-coat ornamentation. No seed heteromorphism is observed within individuals of either species, despite differences in the size of the central and lateral flowers within each cyme (heteroanthocarpy). The North American Arthrocnemum subterminale (Parish) Standl. (syn. Salicornia subterminalis Parish) is morphologically distant from Eurasian Arthrocnemum or Salicornia/Sarcocornia group and should be excluded from these genera. The genus Arthrocnemum now comprises only two species (A. macrostachyum and A. franzii), distributed in the Mediterranean area, Macaronesia, West Tropical Africa and the Saharo-Arabian region. A generic description is here elaborated, clearly delimiting Arthrocnemum from morphologically similar species of Sarcocornia. A list of current species previously considered as Arthrocnemum is provided. It is argued that the taxonomic status of Salicornia mucronata Lag. (1817), mentioned in some references as a synonym of Salicornia macrostachya Moric. (1820) [≡Arthrocnemum macrostachyum (Moric.) K.Koch], is indeed a new synonym of Anabasis articulata (Forssk.) Moq. (subf. Salsoloideae). Both names merged with Arthrocnemum macrostachyum – Salicornia virginica Forssk. and Arthrocnemum glaucum (Delile) Ung.-Sternb. var. fasciculatum Sennen were lectotypified. The typification of the genus Arthrocnemum has so far been lacking and requires a special proposal with a conserved type.

Microbulbifer rhizosphaerae sp. nov., isolated from the rhizosphere of the halophyte Arthrocnemum macrostachyum.

A novel, salt-dependent, non-motile, rod-shaped, Gram-stain-negative and non-endospore-forming bacterium, designated strain Cs16bT, was isolated from the rhizosphere of Arthrocnemum macrostachyum, a halophytic plant at the Lebrija marshes (Seville, Spain). Strain Cs16bT was catalase- and oxidase-positive, and able to hydrolyse casein. Growth occurred from 15-40 °C, at pH 6.0-10.0 and with 1-6% (w/v) NaCl. Q-8 was identified as the major ubiquinone and the predominant cellular fatty acids were iso-C15:0, iso-C17:1cis8, iso-C11:0 3-OH, iso-C17:0, C17:0 cyclo and iso-C11:0. The polar lipids profile consisted of phosphatidylethanolamine, phosphatidylglycerol, two unknown glycophospholipids, an unknown aminoglycophospholipid, an unknown aminophospholipid and an unknown phospholipid. The 16S rRNA gene of strain Cs16bT showed 98.1%, 97.8%, and 97.6% sequence similarity with Microbulbifer maritimus CIP 108504T, Microbulbifer taiwanensis DSM 24146T and Microbulbifer gwangyangensis JCM 17800T, respectively. Based on the phenotypic and genotypic features, it is concluded that strain Cs16bT represents a novel species of the genus Microbulbifer, for which the name Microbulbifer rhizosphaerae sp. nov. is proposed. The type strain is Cs16bT (=DSM 28920T=CECT 8799T).

Phylogenetic Assessment Of Arthrocnemum Macrostachyum (Chenopodiaceae) Genotypes, Using Ramp Markers

AbstractRandom amplified microsatellite polymorphism (RAMP) marker technique was employed to test its usefulness for assessing phylogenetic relationships in three genotypes of Arthrocnemum macrostachyum (Moric.) Moris. &amp; 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.

Oilseed halophytes: a potential source of biodiesel using saline degraded lands

The financial and technical aspects of using edible plants as a biodiesel source have been studied extensively, but research on the potential use of salt resistant, non-edible plants for this purpose remains relatively underexplored. Data available on salt tolerance range, seed oil content, composition of fatty acid methyl esters (FAME) and engine performance parameters – Iodine Value (IV), Cetane Number (CN) and Saponification Number (SN) – of 20 salt-resistant plants were examined to assess their suitability for use as diesel engine fuel. Most of the test species were perennial from family Amaranthaceae, exhibiting high salt tolerance. The quantity of their seed oil ranged from 10–30% while nine species contained >25% oil. The SN, IV and CN values varied from 130–206, 29–156 and 38–81, respectively. Based on the above mentioned parameters, seven halophytic plant species – Salicornia fruticosa, Cressa cretica, Arthrocnemum macrostachyum, Alhagi maurorum, Halogeton glomeratus, Kosteletzkya virginica and Atriplex rosea – appear to be promising biodiesel candidates. These non-food plants which can grow using saline resources and have an oil composition suitable for engine efficiency are more salt resistant than Jatropha or other glycophytic feedstock to serve in a bioenergy farming system. Cultivation of such plants for biodiesel production has the additional advantage of reclaiming degraded lands with the environmental benefit of carbon sequestration.

Internal transport of alien and native plants by geese and ducks: an experimental study

Summary Alien plant species are rapidly spreading in aquatic ecosystems around the world, causing major ecological effects. They are typically introduced by humans, after which natural vectors facilitate their further spread. Migratory waterbirds have long been recognised as important dispersal vectors for native and aquatic plants, yet little is known about their role in the spread of alien species. We determined experimentally the potential for long‐distance dispersal of native and alien wetland plants in Europe by two abundant waterfowl: mallards Anas platyrhynchos and greylag geese Anser anser. We fed seeds from two plants alien to Europe and two native plants to 10 individuals of each bird species, testing for the effects of bird and plant species on the potential for dispersal. Intact seeds were retrieved from faeces for up to 4 days after ingestion. The proportion of seeds retrieved intact varied significantly between plant, but not bird, species. Retrieval was highest for the invasive water primrose Ludwigia grandiflora (&gt;35% of ingested seeds), lowest for the invasive cordgrass Spartina densiflora (&lt;3%) and intermediate for the native glasswort Arthrocnemum macrostachyum and seablite Suaeda vera (5–10%). Seed retrieval patterns over time varied between both plant and bird species. Contrary to expectations, seeds were retained in the gut for longer in the smaller mallards. No Spartina seeds germinated after retention for over 8 h, whereas some seeds of the other species germinated even after retention for 72 h. Germinability was reduced by gut passage for Ludwigia and Arthrocnemum seeds. Ludwigia seeds recovered from geese were more likely to germinate than those recovered from mallards. Time to germination was reduced by gut passage for Spartina and Ludwigia, but increased with retention time. Ducks and geese evidently have the potential for long‐distance transport of alien and native plant seeds, with maximal dispersal distances of well over 1000 km. The much greater potential of Ludwigia than Spartina for dispersal by waterfowl is consistent with its faster expansion across Europe. Maximum retention times of wetland seeds have been underestimated in previous experimental studies that lasted only 1–2 days. Contrary to previous studies, wetland plants with large seeds, such as Ludwigia, can still show high potential for long‐distance dispersal. More attention should be paid to the role of waterbirds as vectors of alien plants and to the role of migratory geese as vectors of plants in general.