Morphological description and DNA barcoding study of sand rice (Agriophyllum squarrosum, Chenopodiaceae) collected in Kazakhstan.

BACKGROUND: Sand rice (Agriophyllum squarrosum (L.) Moq.) is an annual shrub-like plant adapted to the mobile sand dunes in desert and semi-desert regions of Asia. It has a balanced nutrient composition with relatively high concentration of lipids and proteins, which results in its nutrition being similar to legumes. Sand rice's proteins contain the full range of essential amino acids. However, calories content is more similar to wheat. These features together with desert stress resistance make sand rice a potential food crop resilient to ongoing climate change. It is also an important fodder crop (on young stages of growth) for cattle in arid regions of Kazakhstan. In our work, sand rice samples were collected from two distant regions of Kazakhstan as a part of the nation-wide project to determine genetic variation of the native flora. RESULTS: Samples were collected in western and southeastern parts of Kazakhstan separated by distances of up to 1300 km. Sequences of the nuclear ribosomal DNA ITS1-5.8S-ITS2 region and the chloroplast matK gene confirmed the identity of species defined by morphological traits. Comparison with GenBank sequences revealed polymorphic sequence positions among Kazakh populations and GenBank references, and suggested a distinction among local populations of sand rice. The phylogenetic analysis of nucleotide sequences showed a clear partition of A. squarrosum (L.) Moq. from Agriophyllum minus Fisch. & C.A. Mey, which grows in the same sand dunes environment. CONCLUSIONS: DNA barcoding analyses of ITS and matK sequences showed a segregation of A. squarrosum from A. minus into separate clades in Maximum-Likelhood dendrograms. ITS analysis can be successfully used to characterize A. squarrosum populations growing quite distant from each other. The data obtained in this work provide the basis for further investigations on A. squarrosum population structure and may play a role in the screening of sand rice plants growing in desert and semi-desert environments of Central Asia and China.

Evaluating sampling strategy for DNA barcoding study of coastal and inland halo-tolerant Poaceae and Chenopodiaceae: A case study for increased sample size.

Environmental conditions in coastal salt marsh habitats have led to the development of specialist genetic adaptations. We evaluated six DNA barcode loci of the 53 species of Poaceae and 15 species of Chenopodiaceae from China's coastal salt marsh area and inland area. Our results indicate that the optimum DNA barcode was ITS for coastal salt-tolerant Poaceae and matK for the Chenopodiaceae. Sampling strategies for ten common species of Poaceae and Chenopodiaceae were analyzed according to optimum barcode. We found that by increasing the number of samples collected from the coastal salt marsh area on the basis of inland samples, the number of haplotypes of Arundinella hirta, Digitaria ciliaris, Eleusine indica, Imperata cylindrica, Setaria viridis, and Chenopodium glaucum increased, with a principal coordinate plot clearly showing increased distribution points. The results of a Mann-Whitney test showed that for Digitaria ciliaris, Eleusine indica, Imperata cylindrica, and Setaria viridis, the distribution of intraspecific genetic distances was significantly different when samples from the coastal salt marsh area were included (P < 0.01). These results suggest that increasing the sample size in specialist habitats can improve measurements of intraspecific genetic diversity, and will have a positive effect on the application of the DNA barcodes in widely distributed species. The results of random sampling showed that when sample size reached 11 for Chloris virgata, Chenopodium glaucum, and Dysphania ambrosioides, 13 for Setaria viridis, and 15 for Eleusine indica, Imperata cylindrica and Chenopodium album, average intraspecific distance tended to reach stability. These results indicate that the sample size for DNA barcode of globally distributed species should be increased to 11-15.

[Estimation of endophytic bacterial diversity in root of halophytes in Northern Xinjiang by high throughput sequencing].

Objective: We studied the diversity of endophytic bacterial communities in different species of halophytes growing in the same saline habitat, and analyzed the effect of rhizosphere soil physicochemical properties on endophytic bacterial communities. Methods: PCR-based Roche FLX 454 pyrosequencing was applied to reveal the diversity of endophytic bacteria. Results: Endophytic bacterial communities of the 16 species of halophytes mainly included 4 phyla, which were Proteobacteria, Tenericutes, Actinobacteria and Firmicutes. In terms of plant species classification, colonial differences existed among plant species at perspectives of composition of bacterial taxa; in the case of plant genus level, endophytic bacteria of different halophyte plant species but belonging to same plant genus exhibited similarity; as to plant family level, Actinobacteria and Proteobacteria comprised the main abundant phyla of the halophytes belonging to Chenopodiaceae; Proteobacteria comprised the main abundant phyla of the halophytes belonging to Zygophyllaceae; Tenericutes comprised the main abundant phyla of the halophytes belonging to Tamaricaceae; Proteobacteria, Fimicutes and Actinobacteria comprised the main abundant phyla of the halophytes belonging to Plumbaginaceae. The Cl- in rhizosphere soil has significant effect on endophytic bacterial community structure. Moreover, there is a strong correlation between bacterial community and the combination of Cl-, Mg2+ and total nitrogen. Conclusion: Halophytes harbors diverse endophytic bacteria. In the same saline habitat, the distribution of endophytic bacteria showed host plant species-specific, and the Cl- in rhizosphere soil was one of the factors determined the endophytic bacterial community.

[Species composition and population structure of plant communities on semi-fixed dunes of the Gurbantongut Desert, China.] / å¤å°”ç­é€šå¤ç‰¹æ²™æ¼ åŠå›ºå®šæ²™ä¸˜æ¤ç‰©ç¾¤è½ç‰©ç§ç»„æˆå’Œç§ç¾¤ç»“æž„.

The objective of this study was to investigate species composition, and predict future development of dominant species on semi-fixed sand dunes in the Gurbantongut Desert. Using the plant height, crown area and volume instead of age structure, the growth and development condition of dominant shrub populations were analyzed. The results showed that totally 23 species were observed, of which Chenopodiaceae occurred the most with 6 genera 8 species, followed by Asteraceae with 5 genera 6 species. The vegetation community of Gurbantunggut Desert was characterized by few species, and simple structure. As a dominant species, Haloxylon persicum was distributed mainly on the top of the dunes and was a stable increasing population. However, the number of H. ammodendron was small. Artemisia ordosica, as an exotic species introduced by vegetation restoration after construction, covered mainly in the windward and the top of dunes. The po-pulation of A. ordosica had an increasing age structure with a strongly increasing potential, which has affected local species composition. The populations of Calligonum leucocladum and Ephedra distachya were lack of seedlings and had few saplings, resulting in the declining age structure. Due to the same distribution habitat, C. leucocladum might be replaced by A. ordosica in the future.

Evidence for a Common Origin of Homomorphic and Heteromorphic Sex Chromosomes in Distinct Spinacia Species.

The dioecious genus Spinacia is thought to include two wild relatives (S. turkestanica Ilj. and S. tetrandra Stev.) of cultivated spinach (S. oleracea L.). In this study, nuclear and chloroplast sequences from 21 accessions of Spinacia germplasm and six spinach cultivars or lines were subjected to phylogenetic analysis to define the relationships among the three species. Maximum-likelihood sequence analysis suggested that the Spinacia plant samples could be classified into two monophyletic groups (Group 1 and Group 2): Group 1 consisted of all accessions, cultivars, and lines of S. oleracea L. and S. turkestanica Ilj. and two of five S. tetrandra Stev. accessions, whereas Group 2 was composed of the three remaining S. tetrandra Stev. accessions. By using flow cytometry, we detected a distinct difference in nuclear genome size between the groups. Group 2 also was characterized by a sexual dimorphism in inflorescence structure, which was not observed in Group 1. Interspecific crosses between the groups produced hybrids with drastically reduced pollen fertility and showed that the male is the heterogametic sex (XY) in Group 2, as is the case in S. oleracea L. (Group 1). Cytogenetic and DNA marker analyses suggested that Group 1 and Group 2 have homomorphic and heteromorphic sex chromosome pairs (XY), respectively, and that the sex chromosome pairs of the two groups evolved from a common ancestral pair. Our data suggest that the Spinacia genus may serve as a good model for investigation of evolutionary mechanisms underlying the emergence of heteromorphic sex chromosome pairs from ancestral homomorphic pairs.

Structural and physiological analyses in Salsoleae (Chenopodiaceae) indicate multiple transitions among C3, intermediate, and C4 photosynthesis.

In subfamily Salsoloideae (family Chenopodiaceae) most species are C4 plants having terete leaves with Salsoloid Kranz anatomy characterized by a continuous dual chlorenchyma layer of Kranz cells (KCs) and mesophyll (M) cells, surrounding water storage and vascular tissue. From section Coccosalsola sensu Botschantzev, leaf structural and photosynthetic features were analysed on selected species of Salsola which are not performing C4 based on leaf carbon isotope composition. The results infer the following progression in distinct functional and structural forms from C3 to intermediate to C4 photosynthesis with increased leaf succulence without changes in vein density: From species performing C3 photosynthesis with Sympegmoid anatomy with two equivalent layers of elongated M cells, with few organelles in a discontinuous layer of bundle sheath (BS) cells (S. genistoides, S. masenderanica, S. webbii) > development of proto-Kranz BS cells having mitochondria in a centripetal position and increased chloroplast number (S. montana) > functional C3-C4 intermediates having intermediate CO2 compensation points with refixation of photorespired CO2, development of Kranz-like anatomy with reduction in the outer M cell layer to hypodermal-like cells, and increased specialization (but not size) of a Kranz-like inner layer of cells with increased cell wall thickness, organelle number, and selective expression of mitochondrial glycine decarboxylase (Kranz-like Sympegmoid, S. arbusculiformis; and Kranz-like Salsoloid, S. divaricata) > selective expression of enzymes between the two cell types for performing C4 with Salsoloid-type anatomy. Phylogenetic analysis of tribe Salsoleae shows the occurrence of C3 and intermediates in several clades, and lineages of interest for studying different forms of anatomy.

Fruit and seed anatomy of Chenopodium and related genera (Chenopodioideae, Chenopodiaceae/Amaranthaceae): implications for evolution and taxonomy.

A comparative carpological study of 96 species of all clades formerly considered as the tribe Chenopodieae has been conducted for the first time. The results show important differences in the anatomical structure of the pericarp and seed coat between representatives of terminal clades including Chenopodium s.str.+Chenopodiastrum and the recently recognized genera Blitum, Oxybasis and Dysphania. Within Chenopodium the most significant changes in fruit and seed structure are found in members of C. sect. Skottsbergia. The genera Rhagodia and Einadia differ insignificantly from Chenopodium. The evolution of heterospermy in Chenopodium is discussed. Almost all representatives of the tribe Dysphanieae are clearly separated from other Chenopodioideae on the basis of a diverse set of characteristics, including the small dimensions of the fruits (especially in Australian taxa), their subglobose shape (excl. Teloxys and Suckleya), and peculiarities of the pericarp indumentum. The set of fruit and seed characters evolved within the subfamily Chenopodioideae is described. A recent phylogenetic hypothesis is employed to examine the evolution of three (out of a total of 21) characters, namely seed color, testa-cell protoplast characteristics and embryo orientation.

Effect of drought stress on superoxide dismutase activity in two species of Haloxylon aphyllum and Haloxylon persicum.

Superoxide dismutase activity changes were studied at different periodic tensions using of spectrophotometric measurement of decline in NitroBlue Tetrazolium reduction to Blue Formazan at 560 nm in Haloxylon aphyllum and Haloxylon persicum. The aim of this study was to investigate the changes of superoxide dismutase in applied drought stress in two species of Haloxylon. The results showed that the effect of drought stress on increase in superoxide dismutase activity was significant (p < 0.01) in two haloxylon species. Drought increased enzyme activity at severe tensions. When two haloxylon species were placed under 7 and 14 days no-watering treatments (mild tensions), the enzyme activity was more than its activity in control treatment and less than one in 21 and 28 days no-watering treatments (severe tensions). The enzyme activity in branchlets of Haloxylon aphyllum under 21 and 28 days no-watering treatments was 20.2 and 29.5% more than its activity under control treatment respectively. This activity in Haloxylon persicum was 21.6 and 31.4% more than its activity under control treatment, respectively. With the advent of drought, superoxide dismutase activity increased in two species of haloxylon. The increasing of superoxide dismutase activity in time of dryness advent in Haloxylon aphyllum was more than Haloxylon persicum, which can be raised as an acceptable factor and vindicator in being more resistant of Haloxylon aphyllum to environmental drought.

A broader model for C4 photosynthesis evolution in plants inferred from the goosefoot family (Chenopodiaceae s.s.).

C(4) photosynthesis is a fascinating example of parallel evolution of a complex trait involving multiple genetic, biochemical and anatomical changes. It is seen as an adaptation to deleteriously high levels of photorespiration. The current scenario for C(4) evolution inferred from grasses is that it originated subsequent to the Oligocene decline in CO(2) levels, is promoted in open habitats, acts as a pre-adaptation to drought resistance, and, once gained, is not subsequently lost. We test the generality of these hypotheses using a dated phylogeny of Amaranthaceae s.l. (including Chenopodiaceae), which includes the largest number of C(4) lineages in eudicots. The oldest chenopod C(4) lineage dates back to the Eocene/Oligocene boundary, representing one of the first origins of C(4) in plants, but still corresponding with the Oligocene decline of atmospheric CO(2). In contrast to grasses, the rate of transitions from C(3) to C(4) is highest in ancestrally drought resistant (salt-tolerant and succulent) lineages, implying that adaptation to dry or saline habitats promoted the evolution of C(4); and possible reversions from C(4) to C(3) are apparent. We conclude that the paradigm established in grasses must be regarded as just one aspect of a more complex system of C(4) evolution in plants in general.

Photorespiration and the evolution of C4 photosynthesis.

C(4) photosynthesis is one of the most convergent evolutionary phenomena in the biological world, with at least 66 independent origins. Evidence from these lineages consistently indicates that the C(4) pathway is the end result of a series of evolutionary modifications to recover photorespired CO(2) in environments where RuBisCO oxygenation is high. Phylogenetically informed research indicates that the repositioning of mitochondria in the bundle sheath is one of the earliest steps in C(4) evolution, as it may establish a single-celled mechanism to scavenge photorespired CO(2) produced in the bundle sheath cells. Elaboration of this mechanism leads to the two-celled photorespiratory concentration mechanism known as C(2) photosynthesis (commonly observed in C(3)-C(4) intermediate species) and then to C(4) photosynthesis following the upregulation of a C(4) metabolic cycle.

The need to re-investigate the nature of homoplastic characters: an ontogenetic case study of the 'bracteoles' in Atripliceae (Chenopodiaceae).

BACKGROUND AND AIMS: Within Chenopodioideae, Atripliceae have been distinguished by two bracteoles enveloping the female flowers/fruits, whereas in other tribes flowers are described as ebracteolate with persistent perianth. Molecular phylogenetic hypotheses suggest 'bracteoles' to be homoplastic. The origin of the bracteoles was explained by successive inflorescence reductions. Flower reduction was used to explain sex determination. Therefore, floral ontogeny was studied to evaluate the nature of the bracteoles and sex determination in Atripliceae. METHODS: Inflorescences of species of Atriplex, Chenopodium, Dysphania and Spinacia oleracea were investigated using light microscopy and scanning electron microscopy. KEY RESULTS: The main axis of the inflorescence is indeterminate with elementary dichasia as lateral units. Flowers develop centripetally, with first the formation of a perianth primordium either from a ring primordium or from five individual tepal primordia fusing post-genitally. Subsequently, five stamen primordia originate, followed by the formation of an annular ovary primordium surrounding a central single ovule. Flowers are either initially hermaphroditic remaining bisexual and/or becoming functionally unisexual at later stages, or initially unisexual. In the studied species of Atriplex, female flowers are strictly female, except in A. hortensis. In Spinacia, female and male flowers are unisexual at all developmental stages. Female flowers of Atriplex and Spinacia are protected by two accrescent fused tepal lobes, whereas the other perianth members are absent. CONCLUSIONS: In Atriplex and Spinacia modified structures around female flowers are not bracteoles, but two opposite accrescent tepal lobes, parts of a perianth persistent on the fruit. Flowers can achieve sexuality through many different combinations; they are initially hermaphroditic, subsequently developing into bisexual or functionally unisexual flowers, with the exception of Spinacia and strictly female flowers in Atriplex, which are unisexual from the earliest developmental stages. There may be a relationship between the formation of an annular perianth primordium and flexibility in floral sex determination.

Two reproductively isolated cytotypes and a swarm of highly inbred, disconnected populations: a glimpse into Salicornia's evolutionary history and challenging taxonomy.

The main factor of differentiation at six nuclear microsatellite and seven cpDNA loci in Salicornia from the Mediterranean and Atlantic coasts of France is cytotypic identity, suggesting the presence of a strong reproductive barrier among sympatric cytotypes. Within cytotypes, a substantial proportion of the differentiation between species is due to confounded phylogeographic signal. Conspecific individuals tend to be significantly more related than individuals from different species at the population scale, but mean kinship coefficients among pairs of conspecific and nonconspecific individuals from different populations are not significantly different, suggesting the absence of reproductive isolation among species of the same cytotype. The observed association between morphology and genetic variation within populations would thus result from the selfing mating system (F(is)) = 0.70) generating substantial linkage within the genome, linkage that would quickly disappear among unrelated individuals from different populations. Salicornia species thus function as a network of inbred populations, strongly challenging taxonomic concepts.

Species identification of plant tissues from the gut of An. sergentii by DNA analysis.

There are three commonly used assays to identify plant material in insect guts: the cold anthrone test for fructose, the cellulose staining test for visualizing plant tissue and gas chromatography for seeking unique sugar content profiles. Though sugar and cellulose tests can distinguish between the general sources of sugar meal (nectar versus tissue), they cannot identify the species of plant sources. Even gas chromatography profiles can be problematic; there are reported instances of intra-specific variation as well as inter-specific and intergeneric variation that can mar results. Here, we explore the potential for DNA analysis to help resolve this issue. First, Anopheles sergentii were exposed to branches of two species of highly attractive flowering bushes in the laboratory and the great majority ( approximately 90-98%) were positive for sugar from nectar while very few were positive for cellulose ( approximately 0.5-8%) and DNA (6-19%). Moreover, laboratory An. sergentii showed opposing preferences, tending to obtain sugar from nectar of one plant (Tamarix nilotica) but to feed more on tissue from the other (Ochradenus baccatus). An. sergentii are exposed to a wide variety of plants in their natural desert habitats and in the absence of flowers in the dry season, they resort to feeding specifically on tissues of a few plants. According to DNA analysis the favorite plants were Suaeda asphaltica, Malva nicaeensis and Conyza dioscoridis, which are succulents that account for less than 1% of vegetation in the area.

Antimicrobial activity of fatty acid methyl esters of some members of Chenopodiaceae.

Fatty acid methyl ester (FAME) extracts of four halophytic plants, viz. Arthrocnemum indicum, Salicornia brachiata, Suaeda maritima and Suaeda monoica belonging to the family Chenopodiaceae, were prepared and their composition was analyzed by GC-MS. The FAME extracts were also screened for antibacterial and antifungal activities. The GC-MS analysis revealed the presence of more saturated fatty acids than unsaturated fatty acids. Among the fatty acids analyzed, the relative percentage of lauric acid was high in S. brachiata (61.85%). The FAME extract of S. brachiata showed the highest antibacterial and antifungal activities among the extracts tested. The other three extracts showed potent antibacterial and moderate anticandidal activities.

Isolation and characterization of CMO gene promoter from halophyte Suaeda liaotungensis K.

The 5'-flanking proximal region of stress-induced gene encoding choline monooxygenase (CMO) was isolated by Adaptor-PCR and TAIL-PCR from halophyte Suaeda liaotungensis K. A total of 2,204 bp DNA sequence was obtained. The transcription start site, which is located at 128 bp upstream to the start ATG, was predicted by the TSSP-TCM program. The functional elements were analysed by PLACE program. The obtained SlCMO gene promoter contains the basic elements: TATA-box, CAAT-box, and stress-induced elements, for example, salt responsive element (GAAAAA), cold responsive elements (CANNTG), ABA (Abscisic Acid) responsive elements (NAACAA), water stress element (CGGTTG), and WUN responsive elements (GTTAGGTTC). Isolation and analysis of the promoter of the CMO gene from S. liaotungensis lays a foundation for characterising the stress-induced promoter elements, studying the relationship between the structure and function of the promoter, and investigating the molecular mechanism of CMO gene regulation.

Morphological study of Salicornieae (Chenopodiaceae) native to Iran.

The tribe Salicornieae Dum. belonging to the subfamily Salicornioideae Kostel (Chenopodiaceae Vent.) includes halophyte plants. These 5 genera and 6 species are distributed in different habitats of Iran. Members of this tribe have reduced vegetative parts, scale like leaves and articulated stems. In this study quantitative and qualitative morphological characters for 46 accessions of Salicornieae were evaluated. Vegetative characters are not sufficient to distinguish these taxa. Our results indicated that vegetative form, globular buds, plant color, stem base disarticulation and presence of node at the base of inflorescence are diagnostic character in this tribe. Besides floral arrangement in inflorescences, bracts shape, color and shape of seeds are important key features in members of Salicornieae in Iran. Seed coat ornamentations and its hairs and color are found to be helpful in distinguishing these taxa. Quantitative characters show variation too, but as they were not significant, they can not help to resolve the taxonomic problems of this tribe in Iran. Based on studied morphological characters, an identification key for members of this tribe in Iran is provided.

Seed protein variations of Salicornia L. and allied taxa in Turkey.

Electrophoretic seed protein patterns of a number of accessions of Salicornia europaea L. sl., S. prostrata Palas, S. fragilis P.W. Ball and Tutin, Sarcocornia fruticosa (L.) A. J. Scott, Sarcocornia perennis (Miller.) A. J. Scott, Arthrocnemum glaucum (Del.) Ung.-Sternb., Microcnemum coralloides (Loscos and Pardo) subsp. anatolicum Wagenitz and Halocnemum strobilaceum (Pall.) Bieb. were electrophoretically analysed on SDS-PAGE. In total 48 different bands were identified. The obtained data have been treated numerically using the cluster analysis method of unweighted pair group (UPGMA). Finally it was determined that all species separated according to seed protein profiles. And the cladogram obtained studied taxa have been given.

[Haloxylon ammodendron community patterns in different habitats along southeastern edge of Zhunger basin].

Low-lying land, slow and gentle desert, and semi-mobile dune are the three different habitats of natural Haloxylon ammodendron community along the southeastern edge of Zhunger Basin in Xinjiang Uygur Autonomous Region. This paper studied the structural characters of H. ammodendron community from the aspects of species structure, species diversity, biomass, and distribution patterns of natural regeneration sapling. The results showed that the species of H. ammodendron community was the richest on low-lying land, the second on slow and gentle desert, and the least on semi-mobile dune. The number of plant species in the three different habitats was 16, 15 and 12, respectively. The amount of H. ammodendron natural regeneration sapling was the largest (6 687 trees x hm(-2)) on semi-mobile dune, but its distribution was not even. Low-lying land had a slightly smaller amount (5 799 trees x hm(-2)) of H. ammodendron natural regeneration sapling than semi-mobile dune, but the distribution of the sapling was more even. The overall evaluation ion was that the natural regeneration of H. ammodendron community was the best on low-lying land. Its total biomass on low-lying land was 19.39 t x hm(-2), while that on slow and gentle desert and semi-mobile dune was 9.32 and 6.69 t x hm(-2), respectively. The distribution patterns of H. ammodendron natural regeneration sapling in different habitats were all aggregatice. The ground of low-lying land was fixed, with fairly good soil moisture and fertility, which was appropriate for the growth of H. ammodendron and the development of H. anmmodendron community, while that of slow and gentle desert and semi-mobile dune was easier to suffer from wind erosion, with poor soil moisture and fertility and fairly serious habitat conditions.

Loss of genetic variation in geographically marginal populations of Atriplex tatarica (Chenopodiaceae).

BACKGROUND AND AIMS: Genetic variability was estimated for Atriplex tatarica from 25 populations in the Czech Republic. Since its north-western range margin is in central Europe, a relationship between marginality and low within-population genetic diversity was tested in accordance with the Central-Marginal Model. METHODS: Population genetic diversity was expressed by assessing patterns of variation at 13 putatively neutral allozyme loci (comprising 30 putative alleles) within and between 25 natural populations of A. tatarica along a north-west-south-east transect in the Czech Republic. KEY RESULTS: Atriplex tatarica is a species of human-made habitats with a mixed mating system and wide geographic distribution. Overall, A. tatarica displayed moderate levels of genetic diversity in comparison with other herbaceous plants. The percentage of loci that were polymorphic was 47.1%, with average values of 1.55, 0.151 and 0.155 for the average number of alleles per polymorphic locus (A), observed heterozygosity (Ho) and expected heterozygosity (He), respectively. There was only weak evidence of inbreeding within populations (FIS=0.031) and significant population differentiation (FST=0.214). Analysis of the data provides no evidence for isolation-by-distance for the whole study area. However, Mantel tests were highly significant for the marginal Bohemian region and non-significant for the central Moravian region. While northern populations of A. tatarica showed significantly lower allelic richness (A=1.462) than populations from the southern part of the study area (A=1.615), they did not differ in observed heterozygosity (Ho), gene diversity (HS), inbreeding within populations (FIS) or population differentiation (FST), despite generally lower values of particular genetic measurements in the marginal region. CONCLUSIONS: Genetic diversity, with the exception of allelic richness, was not significantly lower at the margins of the species' range. This, therefore, provides only weak support for the predictions of the Central-Marginal Model.

Morphology, anatomy and histochemistry of Salicornioideae (Chenopodiaceae) fruits and seeds.

BACKGROUND AND AIMS: The subfamily Salicornioideae (Chenopodiaceae) are a taxonomically difficult group largely due to the lack of diagnostic characters available to delineate tribal- and generic-level boundaries; a consequence of their reduced floral and vegetative features. This study examined the variation in fruits and seeds across both tribes of the Salicornioideae to assess if characters support traditional taxonomic sections. METHODS: Light microscopy, environmental scanning electron microscopy and anatomical ultra-thin sectioning were employed to examine variation in fruits and seeds. Sixty-eight representatives across 14 of the 15 genera currently recognized within the tribes Halopeplideae and Salicornieae were examined to determine whether characters support current taxonomic groups. KEY RESULTS: Characters such as seed coat structure, embryo shape, seed orientation, the forms of seed storage proteins and carbohydrates show variation within the Salicornioideae and may be phylogenetically useful. The campylotropous ovule typical of the Chenopodiaceae generally results in a curved embryo; however, many Halosarcia and Sclerostegia species have straight embryos and in Salicornia and Sarcocornia the large peripheral embryo appears bent rather than curved. Seed coat ornamentation of Microcnemum and Arthrocnemum is distinct from other Salicornioideae as the elongated epidermal cells of the exotesta have convex walls. Histochemical stains of anatomical sections of cotyledon cells showed protein bodies were variable in shape, and starch grains were present in some species, namely Salicornia bigelovii, S. europaea and Allenrolfea occidentalis. CONCLUSIONS: While fruits and seeds were found to be variable within the subfamily, no synapomorphic characters support the tribe Halopeplideae as these genera have crustaceous seed coats, curved embryos and abundant perisperm; features characteristic of many of the tribe Salicornieae. The endemic Australian genera are closely related and few seed and fruit characters are diagnostic at the generic level. Nineteen characters identified as being potentially informative will be included in future phylogenetic analyses of the subfamily.