Anatomical study and histochemical analysis of Artemisia leucodes Schrenk.

The study of anatomical structure of the aerial part of Artemisia leucodes Schrenk. was carried out, and in this regard, the anatomical and diagnostic features of A. leucodes raw materials were revealed: epidermal cells of an elongated shape, mesophyll in the leaves is columnar, the stem has a fascicular structure, collenchymal mechanical structures are present in the stem ribs. Histochemical analysis shows that the secretory structures of A. leucodes produce sesquiterpene lactones and essential oils, as was confirmed by a chemical study of the aerial parts of A. leucodes. Sesquiterpene lactones anhydroaustricin, matricarin, leucomisin, grossmizin, 5ß(H)-austricin, were isolated from the ethanol extract of A. leucodes by column chromatography on silica gel. By hydrodistillation of anthodium, buds, and leaves an essential oil was obtained, according to chromatography-mass spectrometry, the major component of which was l-camphor - 39.00% and camphene - 9.31%, 1.8-cineole (eucalyptole) - 6.20%. The obtained data on diagnostic features, determination of the localization of secondary metabolites and chemical composition allow us to identify and standardize the medicinal raw materials of A. leucodes, what guarantees quality, and also allow more rational use of A. leucodes in pharmaceutical production.

CHEMOTYPIC Variation in Volatiles and Herbivory for Sagebrush.

Plants that are damaged by herbivores emit complex blends of volatile compounds that often cause neighboring branches to induce resistance. Experimentally clipped sagebrush foliage emits volatiles that neighboring individuals recognize and respond to. These volatiles vary among individuals within a population. Two distinct types are most common with either thujone or camphor as the predominate compound, along with other less common types. Individuals respond more effectively to cues from the same type, suggesting that some of the informative message is contained in the compounds that differentiate the types. In this study, we characterized the chemical profiles of the two common types, and we examined differences in their microhabitats, morphologies, and incidence of attack by herbivores and pathogens. Analysis by gas chromatography coupled with mass spectrometry revealed that the camphor type had higher emissions of camphor, camphene, and tricyclene, while the thujone type emitted more α-thujone, ß-thujone, (Z)-salvene, (E)-salvene, carvacrol, and various derivatives of sabinene. We were unable to detect any consistent morphological or microhabitat differences associated with the common types. However, plants of the thujone type had consistently higher rates of damage by chewing herbivores. One galling midge species was more common on thujone plants, while a second midge species was more likely to gall plants of the camphor type. The diversity of preferences of attackers may help to maintain the variation in volatile profiles. These chemical compounds that differentiate the types are likely to be informative cues and deserve further attention.

Host-parasite relationship between colonial terns and bacteria is modified by a mutualism with a plant with antibacterial defenses.

Predator-prey and host-parasite interactions and mutualisms are common and may have profound effects on ecosystems. Here we analyze the parasitic and mutualistic associations between three groups of organisms: the plant Artemisia maritima, bacteria, and a colonial seabird (the sandwich tern Sterna sandvicensis) that breeds in dense colonies covered in feces produced by both adults and chicks. A disproportionately large fraction of colonies of the sandwich tern in Denmark were located in patches covered by A. maritima. This association was specific for the densely colonial sandwich tern, but was not present for four other sympatric species of terns that breed in much less dense colonies. A. maritima reduced the abundance of pathogenic Staphylococcus on chicken eggshells in a field experiment. Recruitment by sandwich terns breeding in patches of A. maritima was 18 % higher than for sandwich terns breeding in the absence of A. maritima. A. maritima benefitted from the association with sandwich terns due to the supply of nutrients from feces and uneaten food lost by young. These findings are consistent with sandwich terns exploiting the association with A. maritima and its antimicrobial properties to improve their reproductive success, while sandwich terns and A. maritima are involved in a mutualistic interaction.

Deep sequencing of amplicons reveals widespread intraspecific hybridization and multiple origins of polyploidy in big sagebrush (Artemisia tridentata; Asteraceae).

PREMISE OF THE STUDY: Hybridization has played an important role in the evolution and ecological adaptation of diploid and polyploid plants. Artemisia tridentata (Asteraceae) tetraploids are extremely widespread and of great ecological importance. These tetraploids are often taxonomically identified as A. tridentata subsp. wyomingensis or as autotetraploids of diploid subspecies tridentata and vaseyana. Few details are available as to how these tetraploids are formed or how they are related to diploid subspecies. • METHODS: We used amplicon sequencing to assess phylogenetic relationships among three recognized subspecies: tridentata, vaseyana, and wyomingensis. DNA sequence data from putative genes were pyrosequenced and assembled from 329 samples. Nucleotide diversity and putative haplotypes were estimated from the high-read coverage. Phylogenies were constructed from Bayesian coalescence and neighbor-net network analyses. • KEY RESULTS: Analyses support distinct diploid subspecies of tridentata and vaseyana in spite of known hybridization in ecotones. Nucleotide diversity estimates of populations compared to the total diversity indicate the relationships are predominately driven by a small proportion of the amplicons. Tetraploids, including subspecies wyomingensis, are polyphyletic occurring within and between diploid subspecies groups. • CONCLUSIONS: Artemisia tridentata is a species comprising phylogenetically distinct diploid progenitors and a tetraploid complex with varying degrees of phylogenetic and morphological affinities to the diploid subspecies. These analyses suggest tetraploids are formed locally or regionally from diploid tridentata and vaseyana populations via autotetraploidy, followed by introgression between tetraploid groups. Understanding the phylogenetic vs. ecological relationships of A. tridentata subspecies will have bearing on how to restore these desert ecosystems.

Essential oil composition of Artemisia herba-alba from southern Tunisia.

The composition of the essential oil hydrodistilled from the aerial parts of 18 individual Artemisia herba-alba Asso. plants collected in southern Tunisia was determined by GC and GCMS analysis. The oil yield varied between 0.68% v/w and 1.93% v/w. One hundred components were identified, 21 of of which are reported for the first time in Artemisia herba-alba oil. The oil contained 10 components with percentages higher than 10%. The main components were cineole, thujones, chrysanthenone, camphor, borneol, chrysanthenyl acetate, sabinyl acetate, davana ethers and davanone. Twelve samples had monoterpenes as major components, three had sesquiterpenes as major components and the last three samples had approximately the same percentage of monoterpenes and sesquiterpenes. The chemical compositions revealed that ten samples had compositions similar to those of other Artemisia herba-alba essential oils analyzed in other countries. The remaining eight samples had an original chemical composition.

Responses to air temperature and soil moisture of growth of four dominant species on sand dunes of central Inner Mongolia.

Little attention has been paid to how four dominant shrub species distributed in semi-arid areas respond to the combined effects of temperature and water supply. Seedlings of four species were grown in a glasshouse for eight weeks at air temperatures of 12.5/22.5, 15/25, 17.5/27.5, and 20/30 degrees C (night/day) and with water supplies of 37.5, 75, 112.5, and 150 mm per month. When temperatures were 17.5/27.5 and 20/30 degrees C relative growth rate (RGR) decreased for Artemisia ordosica, A. sphaerocephala, and Hedysarum laeve but not for Caragana korshinskii. RGR increased with increasing water availability for all four species and most treatments. In response to changing water availability, the RGR tended to correlate mainly with the physiological trait (net assimilation rate, NAR) and with dry matter allocation traits (below-ground to above-ground dry matter and leaf mass ratio). A higher ratio of below to above-ground dry matter for all four species under most treatments (0.3-1.7) and water-use efficiency (1.4-9.2 g kg(-1)) may explain how all four species survive drought. Higher temperatures may be harmful to A. ordosica and A. sphaerocephala, under current precipitation levels (average 75 mm per month from mid-June to mid-August). These findings support the proposal that A. ordosica mixed with C. korshinskii will prove optimal for re-vegetation of degraded areas of the Ordos plateau.

The design and evaluation of placebo material for crude herbals: Artemisia afra herb as a model.

Herbal materials are known to present significant challenges with regard to designing credible placebos. This study intended to demonstrate the possibility of designing placebo material for crude herbals and used Artemisia afra, a popular traditional herbal medicine in South Africa, as a model. To produce the placebo, step-wise solvent extractions were conducted on the plant leaves and the process was monitored spectrophotometrically and using high performance liquid chromatography (HPLC) with diode array detection. The odour and taste between the placebo and A. afra was matched by inclusion of linalool and sodium saccharin, respectively. The muscle relaxant activity of the placebo was evaluated using an isolated guinea-pig tracheal muscle preparation. The UV absorbance of the extracts and the HPLC chromatograms, showed that most of the phytochemical constituents had been removed and the placebo closely resembled the A. afra leaves. The EC(50) of the placebo and the leaves were 4846.00 and 68.49 mg/mL, respectively, which showed that not only did the A. afra leaves possess muscle relaxant activity, but that the placebo did not possess any significant activity compared with the A. afra leaves (p value 0.0001). These results demonstrated that it is possible to design credible, pharmacologically inert placebo material for crude herbals.

Fine root distribution and persistence under field conditions of three co-occurring Great Basin species of different life form.

Fine roots of an annual grass, a perennial grass and a perennial shrub were examined. Based on life histories and tissue composition, we expected the greatest root persistence for the shrub and shortest for the annual grass. Roots were observed with minirhizotrons over 2 yr for number, length and diameter changes. A Cox proportional hazard regression correlated root persistence with soil water, depth, diameter and date of production. In 2001, grass roots had similar persistence times, but shrub roots had the shortest. In 2002, the annual had the longest median root persistence, the perennial grass intermediate and the perennial shrub had the shortest. All species responded similarly to the magnitude of seasonal precipitation; root numbers increased with favorable soil moisture and disappeared with drying; fewer, thinner roots at greater soil depths were found in the drier year (2001). Root persistence increased with soil moisture, diameter and earlier appearance in the spring. Plasticity in root morphology and placement was influenced by water availability, yet persistence was surprisingly contrary to expectations.

Molecular phylogeny of Subtribe Artemisiinae (Asteraceae), including Artemisia and its allied and segregate genera.

BACKGROUND: Subtribe Artemisiinae of Tribe Anthemideae (Asteraceae) is composed of 18 largely Asian genera that include the sagebrushes and mugworts. The subtribe includes the large cosmopolitan, wind-pollinated genus Artemisia, as well as several smaller genera and Seriphidium, that altogether comprise the Artemisia-group. Circumscription and taxonomic boundaries of Artemisia and the placements of these small segregate genera is currently unresolved. RESULTS: We constructed a molecular phylogeny for the subtribe using the internal transcribed spacers (ITS) of nuclear ribosomal DNA analyzed with parsimony, likelihood, and Bayesian criteria. The resulting tree is comprised of three major clades that correspond to the radiate genera (e.g., Arctanthemum and Dendranthema), and two clades of Artemisia species. All three clades have allied and segregate genera embedded within each. CONCLUSIONS: The data support a broad concept of Artemisia s.l. that includes Neopallasia, Crossostephium, Filifolium, Seriphidium, and Sphaeromeria. However, the phylogeny excludes Elachanthemum, Kaschgaria, and Stilnolepis from the Artemisia-group. Additionally, the monophyly of the four subgenera of Artemisia is also not supported, with the exception of subg. Dracunculus. Homogamous, discoid capitula appear to have arisen in parallel four to seven times, with the loss of ray florets. Thus capitular morphology is not a reliable taxonomic character, which traditionally has been one of the defining characters.

[Morphological and microscopic identification of herba artemisiae scopariae and its adulterants].

Pharmacognostical studies of Herba Artemisiae Scopariae and its adulterants were compared on morphological and microscopic characteristics. The detailed characteristics of powder microscopic identification were described.

[Pharmacognostical identification of Artemisia argyi and Artemisia indica].

This paper reported the identification of Artemisia argyi and A. indica on their macroscopical and microscopical chracteristics, TLC and UV spectra. It provides a basis for their differentication, exploitage and utilization.