Equisetum Telmateia Research Articles

Green Synthesis of Ag and Cu Nanoparticles Using E. telmateia Ehrh Extract: Coating, Characterization, and Bioactivity on PEEK Polymer Substrates.

PEEK-based implant materials have gained increasing attention as an alternative to titanium due to their biocompatibility and bone-like elasticity. However, PEEK's surface quality and wear resistance are lower than those of metals. This study aimed to enhance the bioactivity and surface quality of PEEK by coating it with silver and copper nanoparticles synthesized via a green method using Equisetum telmateia Ehrh. extract. PEEK samples (Ø 25 mm, 3 mm thick) were coated with single and double layers using spray (airbrush-spray) and drop-coating methods. Comprehensive analyses including SEM, EDX, FT-IR, UV-Vis, surface roughness, release studies, antioxidant and cytotoxicity activity, and antibacterial tests were conducted on the coated samples. The results demonstrated that AgNPs and CuNPs coatings significantly improved the surface quality of PEEK. SEM analysis revealed particle sizes ranging from 48 to 160 nm for AgNPs and 50-135 nm for CuNPs, with superior dispersion obtained using the airbrush-spray method. Surface roughness measurements showed a reduction of 17-33% for AgNPs-coated samples and 7-15% for CuNPs-coated samples compared to uncoated PEEK, with airbrush-spray coatings providing smoother surfaces. Antioxidant activity tests indicated that AgNPs provided 35% higher antioxidant activity compared to CuNPs. Additionally, antibacterial tests revealed that AgNPs exhibited a higher zone of inhibition (up to 14 mm for S. aureus and 18 mm for E. coli) compared to CuNPs, which exhibited zones of 8 mm and 10 mm, respectively. This study concludes that green-synthesized AgNPs, in particular, enhance the bioactivity and surface properties of PEEK, making it a promising material for biomedical applications such as infection-resistant implants.

Vegetation and water of lowland spring-wells in Po Plain (Northern Italy): ecological features and management proposals

Spring-wells (lowland springs, “fontanili”) are elements of Po Plain (Northern Italy) with ecological and historical importance. There, spring-water flows naturally and rises to the surface at a relatively constant temperature, generating unique ecosystems dependent on the groundwater outflow. Despite their importance, they are endangered by degradation processes as the expansion of urban areas and/or the intensification of agriculture, very marked in Po Plain. This research describes four spring-wells of Po Plain from a botanical and ecological perspective through phytosociological relevés and different ecological indexes. Water chemical-physical features are also considered (pH, temperature and ammonium ion, nitrite, nitrate, orthophosphate, chloride and organic matters contents). Plant communities of the spring-well beds show a low number of species (5.8 ± 2.9) but also no exotic species while the vegetation of the banks has a high number of species (32.4 ± 9.8) but several of them are exotic/ornamental. The low value of the Ecological Index of Maturity of the vegetation of the banks (EIM = 4.4 ± 1.5) indicate disturbances, however moderate compared to the surrounding corn fields (EIM ~ 0). All the water samples has high ammonium content (> 0.50 ppm), the water of the spring-well B results the most polluted and both algae and Callitriche obtusangula (rare native species) grow largely in it, while spring-well C has less phosphates and more nitrite and is marked by Equisetum telmateia. Management proposals to protect and enhance the studied spring-wells, as the gradual removal of exotic species and the planting of native species, are discussed.

Antioxidant, Enzyme Inhibitory and Calcium Oxalate Anti-crystallization Activities of Equisetum telmateia Ehrn.

Equisetum L. is the only genus of the Equisetaceae family, which commonly known as horsetails, in English and atkuyruğu or kırkkilit in Turkish. In traditional medicine, Equisetum telmateia Ehrh. is used in diseases of the urinary system, such as pyelonephritis, prostatic hypertrophy, and cystitis. Besides, this species is known to be used by humans to treat kidney stones or kidney sand. The extracts were obtained from the aerial parts of the E. telmateia using three different extraction methods (maceration, Soxhlet, ultrasonic bath) and their antioxidant (ABTS, CUPRAC), anti-urease and anticholinesterase activities were examined. Also, calcium oxalate anti-crystallization activity of Soxhlet methanol extract showing strong antioxidant activity was determined. Soxhlet methanol extract exhibited stronger ABTS radical scavenging (0.0676 mM Trolox/mg extract) and cupric ion reducing/antioxidant (4.351 mM Trolox/mg extract) activity than other extracts. Soxhlet methanol (65.528%) and maceration methanol (61.965%) extracts showed the strongest anticholinesterase activity. In the anti-urease assay, it was found that Soxhlet petroleum ether extract (15.302%) had the highest anti-urease activity. Furthermore, the data obtained showed that the Soxhlet methanol extract had high efficacy in the nucleation and aggregation phase of calcium oxalate crystals. These results prove that Soxhlet methanol extract has antioxidant, anticholinesterase and anti-crystallization capabilities. Therefore, this extract can be used in the future as an antioxidant and anticholinesterase agent as well as the treatment and / or prevention of stone formation.

Combined Effects of Phosphate Solubilizing Bacteria and Nanosilica on the Growth of Land Cress Plant

The present study was done to isolate and characterize two strains of phosphate solubilizing bacteria from rhizospheres of acacia, sugar beet, and wheat, then determine synergic effects of nanosilica and these strains on the vegetative growth of land cress plant. Isolates identification was performed using physiological, morphological, biochemical tests, and 16S ribosomal ribonucleic acid sequencing. Nanosilica was extracted from Equisetum telmateia and characterized via X-ray diffraction, scanning electron microscopy, dynamic light scattering, Brunauer–Emmett–Teller, and X-ray fluorescence techniques. The size and the purity of extracted silica powder were about 30 nm, 97.5 %, respectively. Two strains, namely, Pseudomonas stutzeri and Mesorhizobium sp. were the most efficient strains to grow and solubilize phosphorus in the presence of 860 mM NaCl and various pH conditions. The highest growth of these two strains was observed at 0.05 and 0.07 ppm of nanosilica. The highest amount of dry weight of shoot and root of land cress plant was recorded with the simultaneous application of these strains in combination with nanosilica. The combination of nanosilica and these strains enhanced the soil nitrogen and phosphorus content and the vegetative growth of land cress plant.

Desiccation Tolerance in Chlorophyllous Fern Spores: Are Ecophysiological Features Related to Environmental Conditions?

Fern spores of most species are desiccation tolerant (DT) and, in some cases, are photosynthetic at maturation, the so-called chlorophyllous spores (CS). The lifespan of CS in the dry state is very variable among species. The physiological, biochemical, and biophysical mechanisms underpinning this variability remain understudied and their interpretation from an ecophysiological approach virtually unexplored. In this study, we aimed at fulfilling this gap by assessing photochemical, hydric, and biophysical properties of CS from three temperate species with contrasting biological strategies and longevity in the dry state: Equisetum telmateia (spore maturation and release in spring, ultrashort lifespan), Osmunda regalis (spore maturation and release in summer, medium lifespan), Matteuccia struthiopteris (spore maturation and release in winter, medium-long lifespan). After subjection of CS to controlled drying treatments, results showed that the three species displayed different extents of DT. CS of E. telmateia rapidly lost viability after desiccation, while the other two withstood several dehydration–rehydration cycles without compromising viability. The extent of DT was in concordance with water availability in the sporulation season of each species. CS of O. regalis and M. struthiopteris carried out the characteristic quenching of chlorophyll fluorescence, widely displayed by other DT cryptogams during drying, and had higher tocopherol and proline contents. The turgor loss point of CS is also related to the extent of DT and to the sporulation season: lowest values were found in CS of M. struthiopteris and O. regalis. The hydrophobicity of spores in these two species was higher and probably related to the prevention of water absorption under unfavorable conditions. Molecular mobility, estimated by dynamic mechanical thermal analysis, confirmed an unstable glassy state in the spores of E. telmateia, directly related to the low DT, while the DT species entered in a stable glassy state when dried. Overall, our data revealed a DT syndrome related to the season of sporulation that was characterized by higher photoprotective potential, specific hydric properties, and lower molecular mobility in the dry state. Being unicellular haploid structures, CS represent not only a challenge for germplasm preservation (e.g., as these spores are prone to photooxidation) but also an excellent opportunity for studying mechanisms of DT in photosynthetic cells.

The Comparative Study of Equisetum pratense, E. sylvaticum, E. telmateia: Accumulation of Silicon, Antioxidant and Antimicrobial Screening

The objective of the current study is represented by the determination of silica and a phytochemical screening of phenolic derivates of some Equisetum species. The antioxidant and antimicrobial activity for Equisetum pratense Ehrh.,, Equisetum sylvaticum L. and Equisetum telmateia Ehrh. (sin. Equisetum maximum Lam.) were also investigated. The concentration of silicon (Si) in plants was determined by the spectrophotometric method using previous treatment with NaOH 50% both for the stem and the nodal branches [1]. Results obtained varied from 95.12 to 162.10 SiO2 mg/g dry plant which represents 4.44% to 7.58% Si/100g dry sample. Two types of total extracts were obtained using different solvents and were subjected to qualitative and quantitative chemical analysis considering total phenolic content [2]. The highest concentration of investigated compounds was found in the methanolic extract, E. sylvaticum, 196.5mg/g dry sample. Antioxidant activity was monitored spectrophotometrically and expressed in terms of IC50 (�g/mL) [3]. Values gathered ranged from 261.7 to 429.5 �g/mL. The highest capacity to neutralized DPPH radicals was found in E. sylvaticum. In vitro antimicrobial activity was determined using difusimetric method [4]. Testing was performed on four microorganisms: three strains of bacteria and one species of fungi. Different effects were noticed against the bacteria, furthermore the methanol extract appeared to be most efficient. All extracts showed significand antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Candida albicans (ATCC 90028) and weak to no activity against Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922).

Equisetum telmateia extracts: Chemical compositions, antioxidant activity and antimicrobial effect on the growth of some pathogenic strain causing poisoning and infection

The aerial parts of Equisetum telmateia have been used as a source of biologically active compounds to treat inflammatory, diarrhea, stomach-ache, eczema and mouth infections in traditional medicine. The aim of this work is to evaluate the extraction yield, chemical compositions, antioxidant activity and antimicrobial activity of E. telmateia extracts on Staphylococcus aureus, Bacillus cereus, Escherichia coli, Salmonella typhi and Candida albicans. Chemical compositions E. telmateia was analyzed by high performance liquid chromatography (HPLC) using a C18 column. Analysis of E. telmateia extract by HPLC allowed the identification of Kaempferol 3-O-(6″-O-acetylglucoside) as major compound. The antioxidant activity of extracts was examined by measuring their ability to sequestrate 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The results showed that the DPPH (IC50 = 70.83 ± 0.2 μg/ml) were obtained in the case of supercritical fluid extraction (SFE) extract. MIC microdilution assay were used to determine the antimicrobial activities. Contrary to lower extraction yield (9.6 ± 0.5), the SFE extract exhibited the highest antimicrobial potency with MIC and MBC values of 32 mg/ml against S. aureus compared to the other extracts. The results suggest that SFE method is more appropriate for extraction of E. telmateia biologically active substances with antimicrobial and antioxidant activity than conventional solvent extraction methods.

Distribution, state and conservation of Equisetum telmateia in Lithuania

Abstract Conservation of endangered plant species requires a thorough knowledge about the present state of their populations and habitats as well as identification of current and potential threats. The aim of this research was to evaluate current distribution, state of habitats and the size of populations of Equisetum telmateia (Equisetaceae) in Lithuania as well as to reveal the main threats and requirement for the conservation of this species. Analysis of all available information revealed that E. telmateia currently occurs in seven localities in Lithuania, mainly in the southern part of the country. One formerly recorded population in the south-western part of Lithuania has become extinct. Two reported localities in the environs of Druskininkai (southern Lithuania) are doubtful, because the reports have been based on misidentified specimens. Locality of E. telmateia in the western part of the country probably has been provided erroneously and one locality in the south-eastern region of Lithuania should be verified and the identity of the species requires confirmation. Total area occupied by the stands of E. telmateia in Lithuania is 2.41 ha. Most frequently this species grows in river valleys or close to rivers and occupies alluvial forest habitats, which frequently creates complexes with habitats of mineral-rich springs or springs with tufa formations. Occasionally it grows in the habitats of forests of slopes, tall herb fringe communities and hay meadows. Sporulation of E. telmateia in Lithuania is poor: no fertile shoots were registered in two studied populations, whereas in other localities few fertile shoots were recorded. Evaluation of the status of E. telmateia in Lithuania applying the IUCN criteria resulted in its categorization as a vulnerable species. The main threats for E. telmateia are forest logging and changes in habitat hydrological regime, though wild animals, human activities and invasive plant species also have certain negative impact on the populations of this species.

Antibacterial, antioxidant and anti-proliferative properties and zinc content of five south Portugal herbs

Context: Crataegus monogyna L. (Rosaceae) (CM), Equisetum telmateia L. (Equisataceae) (ET), Geranium purpureum Vil. (Geraniaceae) (GP), Mentha suaveolens Ehrh. (Lamiaceae) (MS), and Lavandula stoechas L. spp. luisieri (Lamiaceae) (LS) are all medicinal. Objective: To evaluate the antioxidant, antiproliferative and antimicrobial activities of plant extracts and quantify individual phenolics and zinc. Material and methods: Aerial part extracts were prepared with water (W), ethanol (E) and an 80% mixture (80EW). Antioxidant activity was measured with TAA, FRAP and RP methods. Phenolics were quantified with a HPLC. Zinc was quantified using voltammetry. Antibacterial activity (after 48 h) was tested using Enterococcus faecalis, Bacillus cereus, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Listeria monocytogenes. Antiproliferative activity (after 24 h) was tested using HEP G2 cells and fibroblasts. Results: Solvents influenced results; the best were E and 80EW. GP had the highest antioxidant activity (TAA and FRAP of 536.90 mg AAE/g dw and 783.48 mg TE/g dw, respectively). CM had the highest zinc concentration (37.21 mg/kg) and phenolic variety, with neochlorogenic acid as the most abundant (92.91 mg/100 g dw). LS was rich in rosmarinic acid (301.71 mg/100 g dw). GP and LS inhibited the most microorganisms: B. cereus, E. coli and S. aureus. GP also inhibited E. faecalis. CM had the lowest MIC: 5830 μg/mL. The antibacterial activity is explained by the phenolics present. LS and CM showed the most significant anti-proliferative activity, which is explained by their zinc content. Conclusion: The most promising plants for further studies are CM, LS and GP.

Eriocaenus (Acari: Trombidiformes: Eriophyoidea), a new genus from Equisetum spp. (Equisetaceae): morphological and molecular delimitation of two morphologically similar species.

Surveys conducted on horsetails, Equisetum spp. (Equisetaceae), in Serbia led to the discovery of a new eriophyoid mite genus while searching for a classical biological control agent against these weeds in New Zealand. Eriocaenus gen. n. is described based on the type species Aceria equiseti Farkas, 1960 (transferred to Eriophyes by Farkas 1965; herein reassigned to the new genus) and Eriocaenus ramosissimi n. sp., a new species discovered on Equisetum ramosissimum Desf. in Serbia. Eriocaenus equiseti (Farkas, 1960), previously only known from Hungary, was found in Serbia for the first time on Equisetum arvense L. and Equisetum telmateia Ehrh., and is redescribed. Species descriptions include line drawings as well as phase contrast (PCLM), differential interference contrast (DIC) and scanning electron (SEM) micrographs. The differential diagnosis between the two Eriocaenus species is supplemented by molecular differentiation of 28S rDNA sequences including D2 fragments for both mites.

Medicinal plants used for cardiovascular diseases in Navarra and their validation from Official sources

Ethnopharmacological relevanceThis paper provides significant ethnopharmacological information on plants used to treat cardiovascular diseases in Navarra, Spain. Material and methodsInformation was collected using semi-structured ethnobotanical interviews with 667 informants (mean age 72; 55.47% women, 44.53% men) in 265 locations. Official sources such as the European Scientific Cooperative on Phytotherapy (ESCOP), German Commission E, World Health Organization (WHO), European Medicines Agency (EMA), European Pharmacopoeia (Ph. Eur.) and Real Farmacopea Española (RFE) monographs were consulted in order to establish the therapeutic efficacy of the reported uses and to obtain further details about quality and safety aspects. A literature review was carried out on the plants that were most frequently cited and were not the subject of a monograph, using a new tool developed by the University of Navarra, UNIKA. ResultsA total of 460 pharmaceutical uses were reported by the informants, belonging to 90 plant species and 39 families, mainly represented by Urticaceae, Rosaceae, Asteraceae, and Equisetaceae. The most frequently used parts of the plants were the aerial parts followed by leaves and flowers. Seventeen out of 90 plants (19%) and 208 out of 460 popular uses (45%) had already been pharmacologically validated in relation to their therapeutic efficacy and safety aspects. ConclusionsThe authors propose to validate five species for their use in cardiovascular diseases: Rhamnus alaternus L., Potentilla reptans L., Equisetum telmateia Ehrh., Centaurium erythraea Rafn and Parietaria judaica L.

Arsenic (As), antimony (Sb), and lead (Pb) availability from Au-mine Technosols: a case study of transfer to natural vegetation cover in temperate climates

Soils from old Au-mine tailings (La Petite Faye, France) were investigated in relation to the natural vegetation cover to evaluate the risk of metals and metalloids (Pb, As, Sb) mobilizing and their potential transfer to native plants (Graminea, Betula pendula, Pteridium aquilinum, Equisetum telmateia). The soils are classified as Technosols with high contamination levels of As, Pb, and Sb. The single selective extractions tested to evaluate available fraction (CaCl2, acetic acid, A-Rhizo, and DTPA) showed low labile fractions (<5 % of bulk soil contents), but still significant levels were observed (up to 342.6 and 391.9 mg/kg for As and Pb, respectively) due to the high contamination levels of soils. Even at high soil contaminations (considered as phytotoxic levels for plants), translocation factors for native plants studied are very low resulting in low concentrations of As, Sb, and Pb in their aerial part tissues. This study demonstrates the important role of (1) native plant cover in terms of "stabilization" of these contaminants, and (2) the poor effectiveness of extraction procedures used for this type of soil assemblages, i.e., rich in specific mineral phases.

Występowanie Equisetum telmateia Ehrh. w użytkach rolnych

&lt;i&gt;Equisetum telmateia&lt;/i&gt; Ehrh. rather often occurs in agricultural lands communities. According to the literature and one's own original research, one constructs his list which contains 16 communities, associations and subassociations &lt;i&gt;(Vicietum tetraspermae, Aphano-Matricarietum, Lathvro-Melandrietum noctiflori, Echinochloo-Setarietum, Galinsogo-Setarietum, Cirsietum rivularis, Cirsetum rivularis caricetosum hartmanii, Scirpetum sylvatici, community with Mentha longifolia, community ,with Equisetum telmateia, Arrhenatheretum medioeuroaeum, Arrhenatheretum mnedioeuropaeum brizetosum mediae, community with Cirsium oleraceuum, Lolio-Cynosuretum, Valeriano-Caricetum flavae, Carlino Dianthetum deltoidis)&lt;/i&gt;. The occurrence of Giant horsetail in such differentiated communities points to its wide ecological scale and the ability to survive in different forms of anthropogenic pressure. The appearance of this species in agricultural land communities may be result of its previous existence on the land that started to be cultivated land or of the vegetative spreading of its rhizomes.

English

In vitro antifungal activity of methanol, acetone and ethyl-acetate extracts from Equisetum telmateia Ehrh., Allium flavum L., Sedum acre L., Sideritis montana L., Marubium peregrinum L. and Xeranthemum anuum L. grown in Serbia, were investigated by microdilution method. Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) have been determined. Testing was conducted against four Aspergillus species - A. flavus, A. fumigatus, A. niger and A. restrictus . All statistical analyses were performed using SPSS package. The tested extracts showed significant antifungal activity against A. restrictus and moderate activity against other Aspergillus spp. The best results showed ethyl acetate extract of S. montana , X. anuum and S. acre .

Fabrication of lignocellulosic fiber–cement composite board and determination of optimum quantities of additives

There is a growing desire to improve properties and use of nonwood plants as supplements to wood materials for wood fiber–cement boards. This study was conducted to determine the suitability of Equisetum telmateia fibers, fly ash (FA) and silica fume gel (SFG) as raw materials with high silica contents for manufacturing structural composite boards with target density and thickness of 1.10 g/cm3 and 13 mm respectively. Fibers were prepared and examined for their effects on Portland cement setting and its strength properties; moreover, FA and SFG were used to counteract the eventual adverse effects of fibers on the hydration properties of the cement matrix. All boards were tested for their thermal conductivity, physical and mechanical properties according to specification JIS standards. It was found that mechanical properties of fiber- cement boards were significantly improved by increasing Equisetum fibers, FA and SFG content, whereas thermal conductivity decreased. With regard to the physical properties, FA as cement replacement led to increase in WA and TS; however, SFG decreased mentioned properties. In general terms, the cement boards containing Equisetum fibers, FA and SFG exhibited superior physical, mechanical and thermal properties, which are important for structural applications, compared to the commercial products.

Equisetum telmateia Ehrh. morphotypes related to anthropogenic habitats

&lt;p&gt;The Giant Horsetail (&lt;em&gt;Equisetum telmateia&lt;/em&gt;) is the only representative of &lt;em&gt;Equisetum &lt;/em&gt;genus included in the list of strictly protected species. In Central and Western Europe the species is found in communities belonging to alliances: &lt;em&gt;Alno-Padion &lt;/em&gt;and &lt;em&gt;Calthion&lt;/em&gt;. With progressing destruction of these biotopes, one can observe the phenomenon of this species moving to the habitats extremely anthropogenic in character.&lt;/p&gt;&lt;p&gt;Frequent and intensive observations of this phenomenon were conducted in the Jasło - Krosno Dale area in southern Poland in three anthropogenic localities. In these localities three interesting, irregular &lt;em&gt;Equisetum telmateia &lt;/em&gt;morphotypes were found: fo. &lt;em&gt;serotinum &lt;/em&gt;subfo. &lt;em&gt;proliferum&lt;/em&gt;, fo. &lt;em&gt;spiralis &lt;/em&gt;and a morphotype with branched shoot.&lt;/p&gt;&lt;p&gt;The phenomenon of morphological plasticity of sporophytes is thought to be connected with the action of genes, which regulate the identity of developing plant organs and their distribution. These genes perform a superior part in relation to the system of growth regulators.&lt;/p&gt;

Distribution of lignin monomers and the evolution of lignification among lower plants

Through application of chemical, biochemical and histochemical analyses, we provide new data on the absence/presence of syringyl lignins in the algal species Mastocarpus stellatus, Cystoseira baccata and Ulva rigida, the bryophytes Physcomitrella patens and Marchantia polymorpha, the lycophytes Selaginella martensii, Isoetes fluitans and Isoetes histrix, the sphenophyte Equisetum telmateia, the ferns Ceratopteris thalictroides, Ceratopteris cornuta, Pteridium aquilinum, Phyllitis scolopendrium and Dryopteris affinis, and the angiosperm Posidonia oceanica. Lignins, and especially syringyl lignins, are distributed from non-vascular basal land plants, such as liverworts, to lycopods and ferns. This distribution, along with the already reported presence of syringyl lignins in ginkgoopsids, suggests that syringyl lignin is a primitive character in land plant evolution. Here, we discuss whether the pathway for sinapyl alcohol recruitment was iterative during the evolution of land plants or, alternatively, was incorporated into the earliest land plants and subsequently repressed in several basal liverworts, lycopods, equisetopsids and ferns. This last hypothesis, which is supported by recent studies of transcriptional regulation of the biosynthesis of lignins, implies that lignification originated as a developmental enabler in the peripheral tissues of protracheophytes and would only later have been co-opted for the strengthening of tracheids in eutracheophytes.

Reasons for the presence or absence of convective (pressurized) ventilation in the genus Equisetum

• The very high rates of convective ventilation reported recently in Equisetum telmateia (up to 120 cm(3) min(-1); internal wind speed, 10 cm s(-1)) prompted this study of a further eight species for the presence or absence of convection and the possible reasons for this. • Convection rates were examined in relation to anatomical pathways, internal resistance to applied pressurized gas flow and stomata. • Only species with interconnecting cortical aerenchyma in branches (when present), shoots and rhizomes induced convection. Rapid humidity-induced convection (HIC) occurred in E. palustre (up to 13 cm(3) min(-1)), with slower rates in E. × schaffneri and E. ramosissimum (≤ 6 and 3 cm(3) min(-1), respectively). Excised shoots of E. hyemale and E. fluviatile showed the potential for HIC (≤ 0.5 and 0.15 cm(3) min(-1), respectively), but not into the rhizomes. High rates were linked to low internal gas flow resistance. No convection was detected in E. scirpoides, E. sylvaticum or E. arvense due to the extremely high resistance to pressure flow, for example, from intercalary meristems and, in the last two, to nonaerenchymatous branches. • Of the nine Equisetum species studied so far, four showed through-flow convection; the other species must rely solely on diffusion for underground aeration in wet soils.

Morphology and Structure of Biomorphous Silica Isolated from Equisetum hyemale and Equisetum telmateia

The family of horsetails (Equisetaceae) is characterized through their high content of silica (SiO2), which is the highest in known vascular plants. This work has focussed on two species of this family, Equisetum hyemale and Equisetum telmateia, where the biomorphous silica is deposited basically as amorphous SiO2 in the outer epidermis of the plants. As source of SiO2, the original plant material was air-dried and carved or powdered. For the isolation process the biomaterial was pre-treated with aceotropic HCl. This pre-treatment has the advantage of the extraction of high amounts of the natural inorganic matrix. In a second step the organic matrix was removed by a thermal oxidative process in the temperature range of 275 - 1200 ◦C to isolate the biogenic silicon dioxide from the perennial plant. Parameters of time, temperature and the thermal gradient were varied to optimize the process and to get products with the highest possible surface area. Furthermore, the particle morphology of the biogenic SiO2 from leaves and stems was examined separately. The silica deposits were characterized by optical microscopy, scanning electron microscopy, infrared spectroscopy, gravimetry, nitrogen sorption analysis, and sedimentation analysis.

The conditions of occurrence of Equisetum telmateia Ehrh. in lowland locality in Western Pomerania

The conditions of occurrence of Equisetum telmateia Ehrh. in lowland locality in Western Pomerania