Search

Salinity-induced lipid alterations have been reported in many plant species; however, how lipid biosynthesis and metabolism are regulated and how lipids work in plant salt tolerance are much less studied. Here, a constitutively much higher phosphatidylserine (PS) content in the plasma membrane (PM) was found in the euhalophyte Salicornia europaea than in Arabidopsis. A gene encoding PS synthase (PSS) was subsequently isolated from S. europaea, named SePSS, which was induced by salinity. Multiple alignments and phylogenetic analysis suggested that SePSS belongs to a base exchange-type PSS, which localises to the endoplasmic reticulum. Knockdown of SePSS in S. europaea suspension cells resulted in reduced PS content, decreased cell survival rate, and increased PM depolarization and K+ efflux under 400 or 800 mM NaCl. By contrast, the upregulation of SePSS leads to increased PS and phosphatidylethanolamine levels and enhanced salt tolerance in Arabidopsis, along with a lower accumulation of reactive oxygen species, less membrane injury, less PM depolarization and higher K+/Na+ in the transgenic lines than in wild-type (WT). These results suggest a positive correlation between PS levels and plant salt tolerance, and that SePSS participates in plant salt tolerance by regulating PS levels, hence PM potential and permeability, which help maintain ion homeostasis. Our work provides a potential strategy for improving plant growth under multiple stresses.

Microbial community structures associated with halophytes and their compositions among different habitats, particularly natural saline sites, have not yet been investigated in detail. In the present study, we examined the diversity and composition of the rhizosphere and root endosphere bacteria of two halophytes, Salicornia europaea L. and Glaux maritima L., collected from two adjacent brackish lakes, Lake Notoro and Lake Tofutsu, in Japan. The bacterial species richness and diversity indices of the two halophytes collected from both lakes showed no significant differences in the rhizosphere or root endosphere. In contrast, beta diversity and taxonomic analyses revealed significant differences in the bacterial communities from each halophyte between the two lakes even though the two locations were natural saline sites, indicating that the bacterial communities for S. europaea and G. maritima both fluctuated in a manner that depended on the geographical location. Common and abundant genera associated with each halophyte across the two lakes were then identified to verify the bacterial genera specifically inhabiting each plant species. The results obtained showed that the composition of abundant genera inhabiting each halophyte across two lakes was distinct from that reported previously in other saline soil areas. These results suggest that each halophyte in different geographical sites had an individual complex bacterial community.

The Chenopodiaceae is one of the families including C4 species among eudicots. In this family, the genus Chenopodium is considered to include only C3 species. However, we report here a transition from C3 photosynthesis to proto-Kranz to C3–C4 intermediate type in Chenopodium. We investigated leaf anatomical and photosynthetic traits of 15 species, of which 8 species showed non-Kranz anatomy and a CO2 compensation point (Γ) typical of C3 plants. However, 5 species showed proto-Kranz anatomy and a C3-like Γ, whereas C. strictum showed leaf anatomy and a Γ typical of C3–C4 intermediates. Chenopodium album accessions examined included both proto-Kranz and C3–C4 intermediate types, depending on locality. Glycine decarboxylase, a key photorespiratory enzyme that is involved in the decarboxylation of glycine, was located predominantly in the mesophyll (M) cells of C3 species, in both M and bundle-sheath (BS) cells in proto-Kranz species, and exclusively in BS cells in C3–C4 intermediate species. The M/BS tissue area ratio, number of chloroplasts and mitochondria per BS cell, distribution of these organelles to the centripetal region of BS cells, the degree of inner positioning (vacuolar side of chloroplasts) of mitochondria in M cells, and the size of BS mitochondria also changed with the change in glycine decarboxylase localization. All Chenopodium species examined were C3-like regarding activities and amounts of C3 and C4 photosynthetic enzymes and δ13C values, suggesting that these species perform photosynthesis without contribution of the C4 cycle. This study demonstrates that Chenopodium is not a C3 genus and is valuable for studying evolution of C3–C4 intermediates. Electronic supplementary material The online version of this article (10.1007/s10265-019-01135-5) contains supplementary material, which is available to authorized users.

A spatial separation of 10 µm between primary and secondary carboxylases is sufficient for a single-cell C4 pathway, even in the absence of any intracellular diffusion barriers., Bienertia cycloptera belongs to a diverse set of plants, recently discovered to perform C4 photosynthesis within individual mesophyll cells. How these plants accomplish high photosynthetic efficiency without adopting Kranz anatomy remains unanswered. By modelling the processes of diffusion, capture, and release of carbon dioxide and oxygen inside a typical Bienertia mesophyll cell geometry, we show that a spatial separation as low as 10 μm between the primary and the secondary carboxylases, can, on its own, provide enough diffusive resistance to sustain a viable C4 pathway at 20 °C, with a CO2 leakage

The genome of Salsola soda allows a transition from C3 to C4 photosynthesis. A developmental transcriptome series revealed novel genes showing expression patterns similar to those encoding C4 proteins., Some species of Salsoleae (Chenopodiaceae) convert from C3 photosynthesis during the seedling stage to the C4 pathway in adult leaves. This unique developmental transition of photosynthetic pathways offers the exceptional opportunity to follow the development of the derived C4 syndrome from the C3 condition within individual plants, avoiding phylogenetic noise. Here we investigate Salsola soda, a little-studied species from tribe Salsoleae, using an ontogenetic approach. Anatomical sections, carbon isotope (δ13C) values, transcriptome analysis by means of mRNA sequencing, and protein levels of the key C4 enzyme phosphoenolpyruvate carboxylase (PEPC) were examined from seed to adult plant stages. Despite a previous report, our results based on δ13C values, anatomy and transcriptomics clearly indicate a C3 phase during the cotyledon stage. During this stage, the entire transcriptional repertoire of the C4 NADP-malic enzyme type is detected at low levels compared to a significant increase in true leaves. In contrast, abundance of transcripts encoding most of the major photorespiratory enzymes is not significantly decreased in leaves compared to cotyledons. PEPC polypeptide was detected only in leaves, correlating with increased PEPC transcript abundance from the cotyledon to leaf stage.

Bienertia cycloptera (Chenopodiaceae) produces two types of leaf foliage colour (reddish and yellowish). In order to determine the role of leaf colour variation in regulating the germination characteristics and salinity tolerance during germination, a study was conducted on seeds collected from plants of both colours. Seeds with and without pulp were germinated under two illumination conditions (12-h light photoperiod and continuous dark), three alternating temperature regimes (15/25°C, 20/30°C and 25/35°C), and several salinity levels at 20/30°C. Germination percentage was significantly higher for seeds without pulp as compared to the seeds with pulp. The response of B. cycloptera seeds to salinity depended on the leaf colour. Thus, the seeds collected from reddish coloured plants were able to tolerate higher salinity compared to those of yellowish coloured plant. The germination recovery results indicate that the seeds from both coloured plants could remain viable in saline condition and they will be able to germinate once the salinity level are decreased by rain. The production of different foliage colours by B. cycloptera seems to be an adaptative strategy which increases the possibility for establishment in unpredictable environments by producing seeds with different germination requirements and salinity tolerance.

Highlight In family Chenopodiaceae, two unique forms of single cell C4 photosynthesis with different evolutionary origins show convergence in structural and biochemical expression of C4 traits during leaf ontogeny., Temporal and spatial patterns of photosynthetic enzyme expression and structural maturation of chlorenchyma cells along longitudinal developmental gradients were characterized in young leaves of two single cell C4 species, Bienertia sinuspersici and Suaeda aralocaspica. Both species partition photosynthetic functions between distinct intracellular domains. In the C4-C domain, C4 acids are formed in the C4 cycle during capture of atmospheric CO2 by phosphoenolpyruvate carboxylase. In the C4-D domain, CO2 released in the C4 cycle via mitochondrial NAD-malic enzyme is refixed by Rubisco. Despite striking differences in origin and intracellular positioning of domains, these species show strong convergence in C4 developmental patterns. Both progress through a gradual developmental transition towards full C4 photosynthesis, with an associated increase in levels of photosynthetic enzymes. Analysis of longitudinal sections showed undeveloped domains at the leaf base, with Rubisco rbcL mRNA and protein contained within all chloroplasts. The two domains were first distinguishable in chlorenchyma cells at the leaf mid-regions, but still contained structurally similar chloroplasts with equivalent amounts of rbcL mRNA and protein; while mitochondria had become confined to just one domain (proto-C4-D). The C4 state was fully formed towards the leaf tips, Rubisco transcripts and protein were compartmentalized specifically to structurally distinct chloroplasts in the C4-D domains indicating selective regulation of Rubisco expression may occur by control of transcription or stability of rbcL mRNA. Determination of CO2 compensation points showed young leaves were not functionally C4, consistent with cytological observations of the developmental progression from C3 default to intermediate to C4 photosynthesis.

Highlight Unlike in glycophytes, NaCl facilitates the nitrate uptake in the euhalophyte S. europaea, while calcium signalling plays important roles in this process., Improving crop nitrogen (N) use efficiency under salinity is essential for the development of sustainable agriculture in marginal lands. Salicornia europaea is a succulent euhalophyte that can survive under high salinity and N-deficient habitat conditions, implying that a special N assimilation mechanism may exist in this plant. In this study, phenotypic and physiological changes of S. europaea were investigated under different nitrate and NaCl levels. The results showed that NaCl had a synergetic effect with nitrate on the growth of S. europaea. In addition, the shoot nitrate concentration and nitrate uptake rate of S. europaea were increased by NaCl treatment under both low N and high N conditions, suggesting that nitrate uptake in S. europaea was NaCl facilitated. Comparative proteomic analysis of root plasma membrane (PM) proteins revealed 81 proteins, whose abundance changed significantly in response to NaCl and nitrate. These proteins are involved in metabolism, cell signalling, transport, protein folding, membrane trafficking, and cell structure. Among them, eight proteins were calcium signalling components, and the accumulation of seven of the above-mentioned proteins was significantly elevated by NaCl treatment. Furthermore, cytosolic Ca2+ concentration ([Ca2+]cyt) was significantly elevated in S. europaea under NaCl treatment. The application of the Ca2+ channel blocker LaCl3 not only caused a decrease in nitrate uptake rate, but also attenuated the promoting effects of NaCl on nitrate uptake rates. Based on these results, a possible regulatory network of NaCl-facilitated nitrate uptake in S. europaea focusing on the involvement of Ca2+ signalling was proposed.

Summary Phylogenetic analysis of independent gains of C4 photosynthesis in Suaedoideae shows differences compared with other C4 lineages in amino acids of phosphoenolpyruvate carboxylase under positive selection and their position relative to functional residues., In subfamily Suaedoideae, four independent gains of C4 photosynthesis are proposed, which includes two parallel origins of Kranz anatomy (sections Salsina and Schoberia) and two independent origins of single-cell C4 anatomy (Bienertia and Suaeda aralocaspica). Additional phylogenetic support for this hypothesis was generated from sequence data of the C-terminal portion of the phosphoenolpyruvate carboxylase (PEPC) gene used in C4 photosynthesis (ppc-1) in combination with previous sequence data. ppc-1 sequence was generated for 20 species in Suaedoideae and two outgroup Salsola species that included all types of C4 anatomies as well as two types of C3 anatomies. A branch-site test for positively selected codons was performed using the software package PAML. From labelling of the four branches where C4 is hypothesized to have developed (foreground branches), residue 733 (maize numbering) was identified to be under positive selection with a posterior probability >0.99 and residue 868 at the >0.95 interval using Bayes empirical Bayes (BEB). When labelling all the branches within C4 clades, the branch-site test identified 13 codons to be under selection with a posterior probability >0.95 by BEB; this is discussed considering current information on functional residues. The signature C4 substitution of an alanine for a serine at position 780 in the C-terminal end (which is considered a major determinant of affinity for PEP) was only found in four of the C4 species sampled, while eight of the C4 species and all the C3 species have an alanine residue; indicating that this substitution is not a requirement for C4 function.

Evolution of C3–C4 intermediate and C4 lineages are resolved in Salsoleae (Chenopodiaceae), and a model for structural and biochemical changes for the evolution of the Salsoloid form of C4 is considered., While many C4 lineages have Kranz anatomy around individual veins, Salsoleae have evolved the Salsoloid Kranz anatomy where a continuous dual layer of chlorenchyma cells encloses the vascular and water-storage tissue. With the aim of elucidating the evolution of C4 photosynthesis in Salsoleae, a broadly sampled molecular phylogeny and anatomical survey was conducted, together with biochemical, microscopic, and physiological analyses of selected photosynthetic types. From analyses of photosynthetic phenotypes, a model for evolution of this form of C4 was compared with models for evolution of Kranz anatomy around individual veins. A functionally C3 proto-Kranz phenotype (Proto-Kranz Sympegmoid) and intermediates with a photorespiratory pump (Kranz-like Sympegmoid and Kranz-like Salsoloid types) are considered crucial transitional steps towards C4 development. The molecular phylogeny provides evidence for C3 being the ancestral photosynthetic pathway but there is no phylogenetic evidence for the ancestry of C3–C4 intermediacy with respect to C4 in Salsoleae. Traits considered advantageous in arid conditions, such as annual life form, central sclerenchyma in leaves, and reduction of surface area, evolved repeatedly in Salsoleae. The recurrent evolution of a green stem cortex taking over photosynthesis in C4 clades of Salsoleae concurrent with leaf reduction was probably favoured by the higher productivity of the C4 cycle.

The physical structure of fodder beets, raw potatoes, ensiled pressed sugar beet pulp, ensiled brewers grains, and corn cob silage was evaluated in diets containing concentrates and either corn silage or grass silage as the roughage source. In one series of experiments, the chewing activity of eight cows was measured over 4 d. The beet pulp and fodder beets were added to the two roughage sources at two ratios [20:80 and 35:65, dry matter (DM) basis]. Potatoes, brewers grains, and corn cob silage were fed in a fixed amount (5 to 6 kg of DM) with corn silage. The chewing indexes (eating and ruminating time per kilogram of DM ingested) for fodder beets and beet pulp averaged 34.3 and 32.3 min/kg of DM, respectively, and were hardly affected by the nature of the roughage or by the inclusion ratio. The chewing indexes for potatoes, brewers grains, and corn cob silage were 23.7, 56.6, and 41.6 min/kg of DM, respectively. In another series of experiments using 8 to 11 cows, the ratio of roughage to concentrates was lowered weekly by 5 percentage units, and the critical rough-age portion of the diet was determined (i.e., the amount just before a lack of physical structure was observed). The roughage source was either fed alone or supplemented with about 4 kg of DM of the experimental feed. The critical roughage portion of the diet decreased when the experimental feeds were added; the decrease was greatest with ensiled pressed beet pulp and was lowest with corn cob silage.

Globally, C4 plants dominate hot, open environments, but this general pattern is underpinned by important differences in the biogeography of C4 lineages. In particular, the species richness of C4 Poaceae (grasses) increases strongly with increasing temperature, whereas that of the major C4 eudicot group Chenopodiaceae correlates positively with aridity. Freezing tolerance is a crucial determinant of biogeographical relationships with temperature and is mediated by photodamage and cellular disruption by desiccation, but little is known about differences between C4 families. This study hypothesized that there is a greater risk of freezing damage via these mechanisms in C4 Poaceae than Chenopodiaceae, that freezing protection differs between the taxonomic groups, and that freezing tolerance of species is linked to arid habitat preference. Chlorophyll fluorescence, water relations, and freezing injury were compared in four C3 and six C4 species of Poaceae and Chenopodiaceae from the same Mongolian flora. Contrary to expectations, freezing-induced leaf mortality and photodamage were lower in Poaceae than Chenopodiaceae species, and unrelated to photosynthetic pathway. The freezing resistance of Poaceae species resulted from constitutive protection and cold acclimation and an ability to protect the photosynthetic apparatus from photodamage. Freezing protection was associated with low osmotic potential and low tissue elasticity, and freezing damage was accompanied by electrolyte leakage, consistent with cell-membrane disruption by ice. Both Chenopodiaceae and Poaceae had the potential to develop cold acclimation and withstand freezing during the growing season, which conflicted with the hypothesis. Instead, freezing tolerance was more closely associated with life history and ecological preference in these Mongolian species.

α- l -Arabinofuranosidase production was performed by solid-state cultivation on a leached sugar beet pulp based medium. The effects of different parameters on enzyme biosynthesis by a thermophilic fungus, Thermoascus aurantiacus , have been studied. The optimal medium composition for maximum α- l -arabinofuranosidase production was sugar beet pulp wetted at 77.8% with a mineral solution at pH 9.5, containing yeast extract at 1.2% as nitrogen source and inoculated by a rate of 2.5 × 10 6 of 5-d-old spores per g of dry matter. Under these conditions, the quantity of α- l -arabinofuranosidase obtained was 1083.3 nkat per g of dry substrate after 140 h cultivation in flasks at 45°C. A biomass of 165 mg per g of dry substrate was measured, giving an enzyme productivity of 48.4 nkat per g of biomass and per h. The optimum pH and temperature for activity of the α- l -arabinofuranosidase in the water extract were pH 4.0 and temperature of 70°C. The α- l -arabinofuranosidase activity was stable for at least 24 h at 30°C and at any pH from 2.5 to 10. At 50°C and pH 4.0, no activity decrease was observed after 48 h, whereas at the same pH, 40% of the initial activity was measured after 4 h incubation at 75°C, these results demonstrate the thermostability of this enzyme.

Two composts were obtained by co-composting of a concentrated depotassified beet vinasse and two agricultural solid residues with different organic matter nature: grape marc (GM; lignin waste) and cotton gin trash (C; cellulosic waste). Composting was carried out in aerated piles with mechanical turning, in controlled conditions during 4 months. After 71 days of composting, a new addition of vinasse similar to the initial addition was made. Changes in temperature, pH and inorganic nitrogen followed a similar path for both mixtures. However, organic matter fractions showed different behaviour depending on the material co-composted with vinasse. Lower organic matter degradation was observed when GM was used as bulking agent due to its high lignin content. No phytotoxicity was detected in the end products. The chemical and physical properties of both vinasse composts suggest their possible use as fertiliser. Copyright (C) 2000 Elsevier Science Ltd. | Two composts were obtained by co-composting of a concentrated depotassified beet vinasse and two agricultural solid residues with different organic matter nature: grape marc (GM; lignin waste) and cotton gin trash (C; cellulosic waste). Composting was carried out in aerated piles with mechanical turning, in controlled conditions during 4 months. After 71 days of composting, a new addition of vinasse similar to the initial addition was made. Changes in temperature, pH and inorganic nitrogen followed a similar path for both mixtures. However, organic matter fractions showed different behaviour depending on the material co-composted with vinasse. Lower organic matter degradation was observed when GM was used as bulking agent due to its high lignin content. No phytotoxicity was detected in the end products. The chemical and physical properties of both vinasse composts suggest their possible use as fertilizer.

Populations of Atriplex canescens var. gigantea were found in Lamta, Bouficha-Enfidha (central Tunisia), and Medenine (southern Tunisia). Literature data concerning the presence of this species in Tunisia are contradictory but now our data confirm its occurrence in the country. On the other hand, this variety is reported in the present paper for the first time both in Tunisia and in North Africa in general. Morphological characters and ecological data are presented, as well as notes about patterns of infraspecific variability of A. canescens. Nomenclatural notes on infraspecific names in A. canescens, as well as on the closely related species A. garrettii, are provided. The types of the names A. canescens var. laciniata, A. canescens var. macilenta, A. garrettii, Obione occidentalis var. angustifolia, and Pterochiton occidentale, that in earlier publications were erroneously considered to be holotypes, are in fact lectotypes (for most of taxa) under Art. 9.10 of the ICN. Isolectotypes were found at CAS (A. canescens var. laciniata and A. canescens var. macilenta), GH (A. canescens var. macilenta), and YU (Atriplex nuttallii).

Southwest Asia is climatically and topographically a highly diverse region in the xeric belt of the Old World. Its diversity of arid habitats and climatic conditions acted as an important area for the evolution and diversification of up to 20 (of 38 known) independent Eudicot C4 origins. Some of these lineages present unique evolutionary strategies like single-cell functioning C4 and C3–C4 switching mechanisms. The high diversity of C4 taxa in Southwest (SW) Asia is also related to the presence of seven phytogeographic zones including the Irano-Turanian region as a center of diversification of many Caryophyllales lineages and the Somali-Masai region (Southern Oman and Yemen) as a center of diversification for C4 Monocots. Nevertheless, the C4 flora of SW Asia has not received detailed attention. This paper presents a comprehensive review of all known C4 species in the area based on a literature survey, own floristic observations, as well as taxonomic, phylogenetic and herbarium data, and δ13C-isotope ratio analysis. The resulting checklist includes a total number of 923 (861 native, of which 141 endemic, and 62 introduced) C4 species, composed of 350 Eudicots and 509 Monocots, most of which are therophytic and hemicryptophytic xerophytes with pluriregional and Irano-Turanian distribution. Two hundred thirty-nine new δ13C-isotope ratios of C4 and C3 plants, as well as some taxonomic changes are presented. An analysis of the distribution of the three main C4 plant families (Chenopodiaceae, Poaceae, and Cyperaceae) in the region in relation to climatic variables indicates that the increase of C4 species follows more or less a latitudinal gradient similar to global patterns, while separate taxonomic groups seem to depend on specific factors as continentality (Chenopodiaceae), average annual temperature (Cyperaceae), and the presence of summer precipitation (Poaceae). An increase of C4 Eudicots in W-E direction even in similar longitudinal belts is explained by a combination of edaphic and climatic conditions. The provided data should encourage a deeper interest in the evolution of C4 lineages in SW Asia and their adaptation to ecological and climatical conditions and awaken interest in the importance of local C4 crops, the conservation of threatened C4 taxa, and awareness of human impacts on the rapid environmental changes in the region.

the consumption of halophytes as healthy gourmet food has increased considerably in the past few years. However, knowledge on the nutritional profile of domesticated halophytes is scarce and little is known on which cultivation conditions can produce plants with the best nutritional and functional properties. In this context, Salicornia ramosissima J. Woods was cultivated in six different salt concentrations, ranging from 35 to 465 mM of NaCl. Both the nutritional profile, the antioxidant capacity, and microbial quality of the produced plants were evaluated including minerals and vitamins. Salt has a marked effect on growth, which decreases for salinities higher than 110 mM. Nonetheless, plants cultivated with intermediate levels of salinity (110 and 200 mM) revealed better antioxidant status with higher amounts of phenolic compounds. Overall, results from this paper indicated that soilless culture systems using low-intermediate salinities produces S. ramosissima plants fit for commercialization and human consumption. XtremeGourmet project [ALG-01-0247-FEDER-017676] FCT Portuguese Foundation for Science and Technology [CCMAR/Multi/04326/2019, MED/UIDB/05183/2020] FCT Portuguese Foundation for Science and Technology European Commission [SFRH/BD/140143/2018] info:eu-repo/semantics/publishedVersion

Saline-alkali plant endophytes similar as marine mangrove plant-derived ones are a big member of microbes inhabiting in tissues of plants without causing obvious disease to their hosts, and they must adapt to the extreme environment of high osmolarity and nutrient deprivation in plant, which are different from terrestrial plant endophytes. Owing to the unique bio-environments, endophytes originated from mangrove plants are being considered as a new resource of natural product research and diverse secondary metabolites with a wide range of bioactivities have been isolated.1, 2, 3 Compared with those of marine mangrove plant-derived endophytes, chemical investigation of saline-alkali plant-derived endophytic fungi have just begun, and only several natural products were isolated from these unique environmental fungi.4,5,6,7Suaeda salsa L., an important model halophytic plant, is distributed at different saline-alkali soil especially at seaside. This plant possesses the ability to absorb salt from saline soils and accumulate them in the plant tissues. Some results revealed that the total salt contents in shoot and root were 23–27% and 10–12%, respectively.8 During our ongoing chemical investigation from unique fungal species as sources of new bioactive natural products, a halo-tolerant endophytic fungus Eurotium rubrum isolated from salt-tolerance wild plant S. salsa L. collected from ‘BoHai’ seaside was chosen to chemical investigation. Previous reports revealed that E. rubrumwas frequently isolated from mangrove plants, and different secondary metabolites with a wide range of bioactivities have been isolated from this endophytic fungus.9, 10, 11, 12, 13 Purification of the solid culture extract of this fungus led to isolate a new anthraquinone named rubrumol (1) with poly-hydroxyl groups together with four known analogs catenarin (2),14 rubrocristin (3),15 emodin (4)16 and 2-methyleurotinone (5).15 In this paper, the structural elucidation for the new compound rubrumol (1) (Figure 1) and bioactivities for compounds 1–5 were present. Several errors on the coupling constants of the known coniothyrinone A (6) were pointed out in this note.17

Objective To isolate and characterize the bioactive secondary metabolites from aerial parts of widespread Chenopodiaceae taxa growing in Saudi Arabia: Salsola villosa Delile. ex Schul. Methods Antibacterial activities of chloroformic extract, fractions and isolate compounds was evaluated against five bacterial strains ( Escherichia coli , Pseudomonas aeruginosa , Salmonella typhimurium , Staphylococcus aureus and Staphylococcus epidermidis ), using a paper disc diffusion method. The purification of compound(s) of chloroform extract was done by chromatographic column of silica gel. The structure elucidation was determined by extensive spectroscopic analysis ( 1 H and 13 C nuclear magnetic resonance, correlation spectroscopy, heteronuclear multiple bond correlation, heteronuclear multiple quantum coherence and nuclear overhauser enhancement spectroscopy) and high resolution electrospray ionization mass spectroscopy analysis. Results Bioactivity guided fractionation of the chloroformic extract led to the isolation of two bioactive compounds: 4-(4′-hydroxy-2′-methylcyclopent-2′-enyloxy)-4-methylcyclopent-2-enol (1) named salsolanol and 4′-[3-(hydroxymethyl)oxiran-2-yl]-3-[(E)-3-hydroxyprop-1-en-1-yl]-6, 2′-dimethoxy [1, 1′-biphenyl]-2-ol (2) named biphenylsalsinol. The antibacterial effects of the chloroform extracts, fractions and isolated compounds 1 and 2 were also evaluated in this work. Results showed that the compounds 1 and 2 exhibited antibacterial activities against four strains: Staphylococcus aureus , Staphylococcus epidermidis , Escherichia coli and Pseudomonas aeruginosa with diameter of zone of inhibition ranging between (9.33 ± 0.94) to (26.33 ± 0.94) mm. Conclusions Based on data presented here, two new natural compounds secondary cyclic alcohol 1 and biphenylpropanoid 2 isolated from bioactive chloroformic extract from aerial parts of Salsola villosa can be responsible for its antibacterial activities.

� Background and Aims Information on the initial growth characteristics of annuals found in Chinese deserts is very limited. The aim of this study was to investigate seed germination and interactive effects of irrigation and seed burial depth in sand on seedling emergence and seedling survival in three annuals (Agriophyllum squarrosum, Bassia dasyphylla and Aristida adscensionis) commonly growing on sand dunes in these regions. � Methods Effects of temperature, light and polyethylene glycol-6000 on seed germination were examined by irrigating seeds sown on filter paper in Petri dishes. Seedling emergence was examined for seeds sown on the surface of, or at different depths (5, 10, 20, 30, 40 and 50 mm) in, sand-filled pots, which were irrigated under different regimes. For seeds buried at a depth of 50 mm, seed viability was examined after irrigation of the pots. � Key Results Seeds of three species germinated at most temperatures recorded between spring and autumn in their native habitats. No seed dormancy was found in any species. For all three species, seedling emergence was most favoured when seeds were buried at a depth of 10 mm. When seeds sown on the sand surface were irrigated, seed germination was considerably suppressed due to water deficiency, but many seeds remained viable. For A. squarrosum and B. dasyphylla, many seeds that were deeply buried and irrigated remained ungerminated but viable, while for A. adscensionis deeply buried seeds germinated, but the seedlings did not emerge due to unfavourable seedling growth in deep sand. � Conclusions Precipitation is the most crucial factor in determining the seasonal emergence of seedlings of the three tested species in thefield. The vertical distribution of seeds in sand determines the proportion of seeds that germinate after precipitation and acts to maintain seed banks over multiple years. a 2005 Annals of Botany Company

Inter-tidal marshes are dynamic diverse ecosystems at the transition zone between terrestrial and ocean environments. Geomorphologically, inter-tidal salt marshes are vegetated land-forms at elevations slightly greater than mean tidal levels that have distributed channels formed under ebb (drainage) tidal flows that widen and deepen in the seaward direction. The drainage channels enable tidal flows to circulate sediments and nutrients through the marsh system during normal tidal events, while depositing sediments during storm or seismic events. This dynamic system encourages considerable biodiversity while simultaneously providing water quality enhancement features that service marsh terrestrial life and marine life in the estuary. Reservoir creation limiting sediment transport, anticipated large increases in sea levels as well as agricultural and urban development have resulted in significant loss of inter-tidal marshes and subsequent adverse impacts on waterfowl, infauna and fisheries. The complex and continuously changing marsh channel hydraulics and sedimentary processes have severely constrained quantitative modeling of these marsh systems such that restoration/creation efforts remain something of an empirical science and further assessments are needed. The purpose of this paper is to outline current understanding of salt marsh hydrodynamics, sediment accretion processes and subsequent response of marsh vegetation to set the stage for assessment of a marsh restoration effort along San Pablo Bay near San Francisco, California. Several kilometers of drainage channels were constructed in a 624 ha disturbed salt marsh to restore tidal circulation and vegetation so as to enhance habitat for threatened species (e.g. clapper rail, harvest mouse, delta smelt and potentially anadromous fish species). Two distinct drainage channel systems ('east' and 'west') were installed having similar channel dimensions common to salt marshes in the region, but having design bankfull tidal prism volumes differing by a factor of two. Following channel excavation, main channel tidal flows and sediment loads as well as marsh sediment accretion rates were monitored to assess the relative success of the excavation in restoring tidal circulation and vegetation (Salicornia spp.) to the marsh. Annual aerial surveys corroborated with ground-truthing indicated that marsh vegetation rapidly expanded, from 40 to 85% coverage several years following excavation. The 'east' channel intake was nearly completely silted in within three years. However, channel surveys and flow measurements indicated that the 'east' channel system tidal prism was only about 1200 m3, more than an order of magnitude less than that of the stable 'west' channel system. Marsh sediment accretion rates were on the order of 7-8 mm yr(-1), a rate common to the Pacific coast region that exceeds estimated sea level rise rates of approximately 2 mm yr(-1). East channel network siltation resulted in storm and spring tidal flood ponding such that marsh vegetation coverage decreased to 51% of the marsh area and related habitat expansion decreased. These results are considered in terms of the primary inter-tidal marsh factors affecting possible restoration/creation strategies.

In higher eukaryotes, the DNA composition of centromeres displays a high degree of variation, even between chromosomes of a single species. However, the long-range organization of centromeric DNA apparently follows similar structural rules. In our study, a comparative analysis of the DNA at centromeric regions of Beta species, including cultivated and wild beets, was performed using a set of repetitive DNA sequences. Our results show that these regions in Beta genomes have a complex structure and consist of variable repetitive sequences, including satellite DNA, Ty3-gypsy-like retrotransposons, and microsatellites. Based on their molecular characterization and chromosomal distribution determined by fluorescent in situ hybridization (FISH), centromeric repeated DNA sequences were grouped into three classes. By high-resolution multicolor-FISH on pachytene chromosomes and extended DNA fibers we analyzed the long-range organization of centromeric DNA sequences, leading to a structural model of a centromeric region of the wild beet species Beta procumbens. The chromosomal mutants PRO1 and PAT2 contain a single wild beet minichromosome with centromere activity and provide, together with cloned centromeric DNA sequences, an experimental system toward the molecular isolation of individual plant centromeres. In particular, FISH to extended DNA fibers of the PRO1 minichromosome and pulsed-field gel electrophoresis of large restriction fragments enabled estimations of the array size, interspersion patterns, and higher order organization of these centromere-associated satellite families. Regarding the overall structure, Beta centromeric regions show similarities to their counterparts in the few animal and plant species in which centromeres have been analyzed in detail.[The sequence data described in this paper have been submitted to the EMBL data library under accession nos. AJ278751,AJ278752, and AJ243337.

Three antifungal compounds, designated xanthobaccins A, B, and C, were isolated from the culture fluid of Stenotrophomonas sp. strain SB-K88, a rhizobacterium of sugar beet that suppresses damping-off disease. Production of xanthobaccin A in culture media was compared with the disease suppression activities of strain SB-K88 and less suppressive strains that were obtained by subculturing. Strain SB-K88 was applied to sugar beet seeds, and production of xanthobaccin A in the rhizosphere of seedlings was confirmed by using a test tube culture system under hydroponic culture conditions; 3 mg of xanthobaccin A was detected in the rhizosphere on a per-plant basis. Direct application of purified xanthobaccin A to seeds suppressed damping-off disease in soil naturally infested by Pythium spp. We suggest that xanthobaccin A produced by strain SB-K88 plays a key role in suppression of sugar beet damping-off disease. Damping-off disease in sugar beet seedlings is caused by a number of soilborne plant pathogens, including Rhizoctonia solani, Pythium ultimum, and Aphanomyces cochlioides .I t is one of the most serious diseases affecting sugar beet production in Japan. Biological control with antagonistic microorganisms has been investigated as a possible means of controlling the disease (17, 19, 20, 23, 25). Homma et al. (10) reported that when applied as a seed coating, a rhizobacterium of sugar beet, strain SB-K88, suppressed seedling damping-off disease almost as effectively as conventional chemical control. Based on certain bacterial characteristics (lack of an umbonate colony form, no growth on a medium containing 4% sodium chloride and 0.1% triphenyl tetrazolium chloride), strain SB-K88 was considered a member of a Stenotrophomonas species (formerly classified as a Xanthomonas species) but not Stenotrophomonas maltophilia (8). It became apparent in the course of investigating the mechanism of disease suppression by strain SB-K88 that this bacterium produces some antifungal substances that are effective in vitro against fungi that cause damping-off disease (18). Because antibiotics are thought to play a major role in disease suppression by rhizobacteria (14, 21), we focused on the relationship between the production of antifungal substances in the culture medium and in the rhizosphere of sugar beet by this strain and the suppression of damping-off disease. We first isolated three antifungal compounds, xanthobaccin A (XB-A), XB-B, and XB-C, from the culture fluid of strain SB-K88. The chemical structure of XB-A was reported recently and is shown in Fig. 1 (6). This compound is a macrocyclic lactam that has a unique 5,5,6-tricyclic skeleton (tricyclo [7.3.0.0 2,7 ]dodecane) and a tetramic acid moiety as a putative chromophore; the plane structure is the same as that of maltophilin, which is produced by S. maltophilia (12). In order to clarify the role of xanthobaccins in disease suppression, we investigated the relationship between the production of XB-A (the major antifungal compound) in vitro and the degree of disease suppression by using less suppressive (LS) strains derived from strain SB-K88. In this paper we also describe the detection and quantification of XB-A produced by strain SBK88 in the rhizosphere of sugar beet seedlings by using a test tube culture system and disease suppression by XB-A applied directly to sugar beet seeds.

A new classification for the cultivated and weed forms of beet is proposed. The paper includes a short description of concept and rules of the new system for the nomenclature of cultivated plants, as published in the 1995 International Code of Nomenclature for Cultivated Plants or Cultivated Plant Code . The classification has an open character, and is formed around the basic elements called culta (singular culton). Culta need not be grouped in a hierarchical way, as in botanical classification (basic elements taxa, singular taxon), but may be grouped according to cultivar. The relevant culta for beet are the named cultivars and the newly formed cultivar groups. A summary of the latest revision of the taxonomy of Beta section Beta , has been included. The description of B. vulgaris subsp. vulgaris is changed, by adding the weed beet populations. Finally, the new classification system for cultivated plants is applied to beet, leading to a proposal to distinguish four cultivar groups: Leaf Beet Group, Garden Beet Group, Fodder Beet Group and Sugar Beet Group. The relationship between the new cultivar groups and those designated by UPOV (International Union for the Protection of New Varieties of Plants) and recommended by the Cultivated Plant Code , is discussed

The mechanism of sex determination in dioecious species of the genus Atriplex (Chenopodiaceae) has not been determined. This paper reports the discovery of a male-specific DNA fragment in the diploid dioecious speciesA. garrettii. DNA samples extracted individually from ten male and ten female plants were bulked by sex. Random amplified polymorphic DNA (RAPD) fragments were generated in the two bulks in order to identify markers that were polymorphic between male and female plants. A total of 158 decamer primers were tested. A 2075 base-pair (bp) male-specific DNA fragment generated with the OPAF-14 primer was identified. The fragment was cloned and partially sequenced and 24-mer primers that exclusively amplified this fragment were constructed. When 124 male plants, 126 female plants, and one hermaphroditic plant were tested individually, the male-specific 2075-bp DNA fragment was present in the hermaphrodite and all but one of the male plants, and was absent in all female plants. A smaller DNA fragment ( ;1800 bp) that was homologous to the 2075bp fragment was amplified from the single male plant that lacked the 2075-bp fragment. Cytogenetic analysis revealed no apparent heteromorphic sex chromosomes. These observations suggest that sex determination in A. garrettii is genetic, with no evidence of heteromorphic sex chromosomes.

A synthetic data set was created by incorporating results from previously published papers on antagonistic and synergistic herbicide interactions between two herbicides applied as a tank mixture or sequentially, and then analyzed on the basis of various properties of the herbicides and target plants. Generally, interactions between herbicides were antagonistic more frequently than synergistic. This trend held no matter whether the interacting herbicides were absorbed by the same or different parts of the plant, had the same or different translocating abilities, had the same or different modes of action, and regardless of whether the target plants were annual or perennial plants, or crops or weeds. Antagonistic interactions occurred much more frequently when the target plants were monocot than dicot, and in the Compositae, Gramineae, or Leguminosae than in the Chenopodiaceae or Convolvulaceae families.

Cellulose was extracted from the roots, stems and stem tips of Salicornia brachiata Roxb. Each crude cellulose sample obtained was fractionated into alpha- and beta-celluloses. The yields of crude cellulose from the stems and stem tips were greatest and lowest, respectively, while the yields of alpha- and beta-celluloses were in the order, rootsstemsstem tips. The cellulose samples were characterized by Fourier transform infrared spectroscopy (FT-IR), solid state cross polarisation magic angle spinning carbon-13 nuclear magnetic resonance spectroscopy (CP/MAS 13C NMR), X-ray diffraction pattern (XRD), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). The data were compared with those of the celluloses (predominantly alpha-cellulose) isolated from Whatman filter paper No. 4 (WFP).

Polycnemum majus A. Br. (Chenopodiaceae) represents one of the Euro-Asian species disappearing as a consequence of man's activities. The paper presents a brief survey of its morphology, distribution (with emphasis on the W part of Czechoslovakia), and taxonomy. The ecological characterization of communities with occurrence ofP. majus is given. From the karyological point of view,P. majus represents a further case of hexaploidy in theChenopodiaceae family, hitherto known in approximately 10% of genera. The basic chromosome number of x=9 is proposed, with respect to chromosome numbers ascertained inP. majus for the first time (2n=54) and inP. arvense (2n=18). The annual hexaploid speciesP. majus was proved to be potentially self-fertile.

Cellulose was extracted from the roots, stems and stem tips of Salicornia brachiata Roxb. Each crude cellulose sample obtained was fractionated into α- and β-celluloses. The yields of crude cellulose from the stems and stem tips were greatest and lowest, respectively, while the yields of α- and β-celluloses were in the order, roots > stems > stem tips. The cellulose samples were characterized by Fourier transform infrared spectroscopy (FTIR), solid state cross polarisation magic angle spinning carbon-13 nuclear magnetic resonance spectroscopy (CP/MAS 13C NMR), X-ray diffraction pattern (XRD), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). The data were compared with those of the celluloses (predominantly α-cellulose) isolated from Whatman filter paper No. 4 (WFP).

Two new infrageneric taxa of Coris- permum L. (Chenopodiaceae) are described: sections Patellisperma and Declinata. Geographical distri- butions and taxonomic comments are provided. Corispermum L. (Chenopodiaceae, Corisper- meae) is a relatively compact and clearly defined genus consisting of ca. 60 almost obligately psam- mophytic species distributed primarily in the arid regions of Asia, with some species also native to temperate Europe, northern Asia, and North Amer- ica. Unfortunately, with the exception of three series described by Klokov (1960) in his monograph of some East European species, no infrageneric system has been proposed for this genus. The present paper may be regarded as the pre- liminary outline of the infrageneric classification of Corispermum (at the sectional level), since the prop- er placement of many insufficiently known species (e.g., sometimes represented in herbaria only by type collections) is not completely clear and remains a task for further study. It is especially true for Central and East Asian species (see Iljin, 1929; Tsien Cho- po & Ma Cheng-gung, 1979).

This paper deals with the partial purification of the pyruvate dehydrogenase complex (PDC) from chloroplasts of spinach and maize mesophyll which hitherto has been isolated only from pea chloroplasts. Starting with membrane free suspensions of lyophilized chloroplasts, and following a high-speed (140000 Xg) centrifugation of this “stromal extract”, the initial specific PDC-activities were concentrated by a factor 10 in the sediment. While most of the purification procedures described earlier resulted in almost complete loss of enzyme activities, a rate zonal sedimentation on linear glycerol gradients allowed for an additional up to 100-fold enrichment of the labile multienzyme complex, albeit with low yields. In contrast to chloroplast PDC from maize mesophyll, inactivation of the spinach complex during glycerol fractionation was due to the dissociation of its loosely bound dihydrolipoyl dehydrogenase component which collected in a lower density fraction of the gradient. Its recombination with PDC constituents of the bottom layer nearly restored initial activities. The chloroplast complex has been identified as true PDC by its substrate specificity for pyru­vate, NAD+, and coenzyme A and the 1:1:1 stoichiometry of its reaction products NADH, CO2, and acetyl-CoA. The chloroplast PDC of both plant species showed the well known higher pH-and Mg-requirements than the mitochondrial complex. The observed species-specific differences in the stability of this multienzyme system suggest a connection with the aggregation state of its components. Apparently, the individual subcomplexes are able to function either together in acetyl-CoA formation or independently from each other, e.g. in the synthesis of acetolactate via hydroxy-ethyl-thiamine pyrophosphate or dihydrolipoyl dehydrogenase activities.

Five days of suitable continuous light induced flowering in the majority ofChenopodium murale L. ecotype 197 plants as early as at the phase of the first pair of leaves. At the time of initiation of the 2nd to 4th pairs of leaves the capacity of plants to flower was reduced, the number of flowering plants being significantly lower under the same inductive light treatment. The capacity to flower increased again at the phase of the 5th and the 6th pairs of leaves. Inductive light treatment brought about a marked growth activation of organs present before induction, shoot apex elongation, precocious formation of new leaves and activation of axillary meristems. The course of these changes in plants of different age is demonstrated. The terminal flower developed during 5 short days following inductive light treatment. The paper shows similarities and differences between long-daymutale L. ecotype 197 and short-day C.rubrum L. ecotype 374 grown under practically uniform conditions.

This paper reports an analysis of the yield of sugar beet crops grown under experimental conditions between 1993 and 1995 in the UK. Crops were either healthy (unstressed) or subjected to drought, infection with Beet yellows virus (BYV) or a combination of both. The study investigated whether the large differences in yield between the crops grown in different seasons and subjected to different stresses could be accounted for by simple relationships between total biomass and radiation interception (εs), transpiration (εw) or εs and εw adjusted for mean saturation deficit (Ωs and Ωw respectively). Mean values of εs, εw, Ωs and Ωw in healthy crops were 1·42 g/MJ, 0·89 g/kg, 6·76 g/kPa/MJ and 4·29 g/kPa/kg respectively. Variations in the dry matter yield between seasons were best accounted for by Ωw and less well by εw or εs. Ωs accounted for least variation in yield between seasons. None of these relationships remained constant in stressed plants; both drought and BYV-infection decreased εs (and Ωs) but Ωw was increased by drought and decreased by BYV-infection. However, in common with healthy crops, seasonal variation in yields was best accounted for by Ωw. Mean values of εs, Ωs, εw and Ωw for all healthy, infected and droughted crops accounted for 61, 50, 88 and 97% of the variation in dry matter yield between experiments respectively. Accurate prediction of the yield of stressed plants requires a knowledge of their infection and drought status. If this information is unavailable then the mean value of Ωw for healthy, infected and droughted crops will provide a reasonable prediction of the yield of such crops.