21,769 research outputs found

    A study of the root surface phosphatase activities of three species of higher plants: Juncus effusus, Phragnutes australis, and Typha latifolia

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    The aim of this project was to investigate a possible link between environmental phosphorus status and the root surface phosphatase activities of three species of emergent macrophytes, with a view to assessing their potential for use as "biondicators". Analyses of water phosphorus concentrations and rates of surface phosphatase activities of Juncus effusus, Phragmites australis and Typha latifolia were carried out on samples from Bakethin Reservoir, Northumberland and Durham University Botanic Garden. Differences were found in water phosphorus concentrations at the sites. Water from Bakethin Reservoir was found to have lower levels of P than water from the Botanic Garden. Interspecific differences at p = 0.0002 were discovered in rates of phosphatase activity between Juncus, Phragmites and Typha. Juncus and Typha were found to exhibit significantly lower rates of phosphatase activity at the Botanic Garden than at Bakethin reservoir (p = 0.026 for Juncus, p = 0.037 for Typha). High rates of phosphatase activity in Juncus and Typha at Bakethin Reservoir corresponded with low concenfrations of environmental phosphorus, so it is possible that root surface phosphatases of both species are inducible in conditions of P- limitation. Juncus and Typha may therefore have the potential for use as bioindicators of environmental phosphorus status. Several practical problems were encountered, and may be of general significance. Rates of phosphatase activity declined rapidly in 100 μM pNPP assays. As a consequence, assays were terminated after 10 min. It was also observed that roots removed after assays had been terminated often showed a yellow coloration, presumably due to the retention of pNP. The accuracy of the pNPP assay relies upon all the pNP produced by the hydrolysis of pNPP being released into solution. The apparent retention of pNP by roots therefore brings the use of the pNPP assay, as a method for determining rates of phosphatase activity in eukaryotes, under scrutiny. One preliminary experiment carried out showed that more pNP was retained by roots under conditions of low pH

    A Typha Angustifolia-like MoS2/carbon nanofiber composite for high performance Li-S batteries

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    A Typha Angustifolia-like MoS2/carbon nanofiber composite as both a chemically trapping agent and redox conversion catalyst for lithium polysulfides has been successfully synthesized via a simple hydrothermal method. Cycling performance and coulombic efficiency have been improved significantly by applying the Typha Angustifolia-like MoS2/carbon nanofiber as the interlayer of a pure sulfur cathode, resulting in a capacity degradation of only 0.09% per cycle and a coulombic efficiency which can reach as high as 99%

    The Growth and Survival of Early Instars of \u3ci\u3eBellura Obliqua\u3c/i\u3e (Lepidoptera: Noctuidae) on \u3ci\u3eTypha Latifolia\u3c/i\u3e and \u3ci\u3eTypha Angustifolia\u3c/i\u3e

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    Larvae of the noctuid moth Bellura obliqua are frequently encountered on Typha latifolia, but less commonly on Typha angustifolia. Experiments were conducted to compare the growth and survivorship of early B. obliqua instars on the two species of cattail. In short-term growth chamber experiments there were no significant differences in the survivorship, relative growth rate (RGR), relative consumption rate (RCR), or the efficiency of conversion of ingested food (ECI) between first-instar larvae reared on leaves of the two species. Third-instar larvae fed stems, however, had a greater RGR and higher ECI when reared on T. lalifolia. Differences in growth are apparently not related to differences in hostplant nitrogen or acid-detergent fiber content. In a long term greenhouse experiment, using transplanted cattails, larvae reared on T. latifolia grew somewhat larger and had a significantly higher survival rate than those reared on T. angustifolia. Host plant structure is postulated to influence larval survivorship. Typha is under consideration for use as a bio-energy crop and planting T. angustifolia may help to reduce infestations in cultivated stands

    An assessment of the cost effectiveness of vegetation harvesting as a means of removing nutrient and metals from ponds

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    This paper reports on an investigation to quantify the mass of pollutants removed from a stormwater retention pond by routine vegetation harvesting. The amount of plants can increase the costs of ponds, and the increased costs of plant maintenance may not be justified by enhanced pollutant removal. This study provides some of the basic information, previously lacking, which is needed to come to such decisions. The study facility was La Costa pond, a retention pond in California used to treat highway runoff. Water quality monitoring data indicate that the pond removed 43 percent of the total nitrogen entering the facility, with 5 to 7 percent directly attributable to harvesting the vegetation – in this case cattails (Typha). The data also indicate that 48 percent of the total annual phosphorus was removed from the runoff, with the harvested vegetation responsible for between 3 and 8 percent. Metal uptake by the vegetation was substantially less than nutrients. Total removal of copper, lead and zinc by the pond varied between 57 and 93 percent, with the harvested vegetation accounting for less than 2 percent of removal. Issues addressed in the paper include the cost implications of harvesting and ways of improving vegetative pollutant removal

    Effect of invasive Typha on sediment nutrient composition of Great Lakes coastal wetlands across a water depth gradient

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    The invasive hybrid cattail, Typha x glauca (hereafter, Typha) forms dense monocultural stands in the shallow waters of Great Lakes coastal wetlands. When Typha dies, its biomass accumulates in nutrient-rich floating mats. I hypothesized that the sediment in wetlands invaded by Typha will have significantly higher levels of carbon and nitrogen due to the accumulation of organic litter by Typha. I analyzed sediment samples from Typha invaded and uninvaded coastal wetlands to determine how biodiversity affects sediment nutrient composition paired with water level gradients. I found that sediment taken from deep water zones had lower concentrations of carbon and nitrogen

    Araneae and Opiliones From \u3ci\u3eTypha\u3c/i\u3e Spp. And \u3ci\u3ePhragmites Australis\u3c/i\u3e Stands of Green Bay, Lake Michigan, and an Exotic Spider Species Newly Reported From the U.S. Great Lakes Region

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    Invertebrates were sampled using pan traps in three paired sets of Typha spp. (cattail) and Phragmites australis (giant reed grass) habitats in Lake Michigan’s Green Bay in June and September 2002. The collection included 34 harvestmen belonging to one species (found at all three sites), and 180 spiders belonging to 25 species in eight families. The two habitats yielded similar numbers of spider taxa, and 16 species were restricted to one of the two habitats. Between 10 and 15 species were found at each site, and only five spider species were collected at all three sites. Four species appear to be new records for the state of Wisconsin, including the linyphiid spiders Hypomma marxii (Keyserling) and Sitalcus ruralis Bishop & Crosby, and the salticid Synageles noxiosus (Hentz). Of particular interest is the first report from the U.S. Great Lakes region of the clubionid spider Clubiona pallidula (Clerck), a species introduced from Eurasia

    The botany and proximate analyses of some edible species of the New Zealand flora : a thesis presented in partial fulfilment of the requirement for the degree of Master of Science in Plant Biology at Massey University

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    1. The edible organs of some New Zealand plant species have been assessed at light microscope level for their botanical basis, and for their nutritional basis by proximate analysis and Plasma Emission Spectrometry. 2. The species investigated, listed by Colenso (1880) as the most valued plant foods of the pre-European Maori, were: Pteridium esculentum (rhizome), Corynocarpus laevigatus (kernel), Elaeocarpus dentatus, (pericarp), Sonchus asper (herb), Calystegia sepium (rhizome), Cyathea medullaris (frond stipe), Cordyline australis (leaf bases, root), Rhopalostylis sapida (apical shoot), Typha orientalis (pollen and rhizome), Beilschmiedia tawa (kernel), Marattia salicina (rhizomal scale), Porphyra columbina (frond), Auricularia polytricha (basidiocarp), Arthropodium cirratum (rhizome), Bolboschoenus fluviatilis (rhizomal tuber), Gastrodia cunninghamii (rhizome) and Asplenium bulbiferum (immature frond). 3. Specimens were collected at the appropriate traditional seasons (except for Gastrodia cunninghamii) and samples prepared by freeze-drying and milling. Samples were also prepared of the cooked organs of Corynocarpus laevigatus, Elaeocarpus dentatus, Sonchus asper, Cyathea medullaris, Beilschmiedia tawa and Porphyra columbina. 4. Analytical determinations were made for lipid, by extraction with di-ethyl ether; nitrogen, by micro-Kjeldahl method and colorimetric measurement of ammonia using indophenol; protein, by Bradford procedure using Coomassie Brilliant Blue and colorimetry; dietary fibre, by Englyst procedure using enzymatic digestion and colorimetry; soluble sugar, by acid hydrolysis and colorimetry; and starch, by enzymatic digestion and colorimetry. 5. Botanical investigations were made following histological procedures and microtechnique using paraffin wax embedding and staining with safranin and fast green; and by differential staining of hand-cut sections using Sudan Blue, iodine and Coomassie Brilliant Blue. 6. Analytical determinations were made for 23 trace, minor and major constituent elements, using inductively-coupled argon plasmas in a simultaneous emission spectrometer. 7. Proximate analyses showed high levels of lipid in Corynocarpus laevigatus, Cyathea medullaris, and Sonchus asper, of protein in Corynocarpus laevigatus, Sonchus asper, Rhopalostylis sapida, Typha orientalis (pollen) and Asplenium bulbiferum; of dietary fibre in Auricularia polytricha, Beilschmiedia tawa, Marattia salicina (root) and Porphyra columbina (uncooked); of soluble sugar in Cyathea medullaris, Cordyline australis (leaf bases and root), Typha orientalis (rhizomes and pollen) and Pteridium esculentum; and of starch in Corynocarpus laevigatus, Elaeocarpus dentatus, Marattia salicina, Calystegia sepium and Gastrodia cunninghamii. 8. High levels of essential minerals and trace elements were measured in many samples, and some excess levels of toxic metals were recorded. 9. The nutritional and ethnobotanical aspects of a pre-European Maori diet were related to the analytical and botanical findings of the investigation

    Micromorphological studies on leaf, fruit and pollen of four species from Typhaceae (Typha laxmannii, T. azerbaijanensis, T. minima and T. lugdunensis) from Iran, and their thematic significance

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    Previous research has made it clear that the intrinsic taxonomy encountered difficulties in identifying speciesin the genus Typha. Therefore, in the present study we have tried to investigate the micromorphological characteristics of pollens, achenes and leaves as well as their systematic utility. Four Typha species identified from the Iranian flora i.e. Typha minima Funk in Hoppe, Typha lugdunensis Chab., Typha azerbaijanensis Hamdi & Assadi and Typha laxmannii Lepechin were taken into consideration. Three of them are easily distinguishable with their closest relative i.e. T. laxmannii Lepechin. Scanning electron microscopy was used to examine pollens, achenes and leaves of the four taxa of the proposed Typha from Iran. A part of these micromorphological studies attempted to investigate achenes, pollens and leaf characteristics of these species under SEM. Interestingly, Typha martini Jordan is also considered as a synonym of T. lugdunensis. The study does not only discuss relationships between close species but it also clarifies their geographical patterns. Finally, a diagnostic key is provided for the distribution of the four Typha species in Iran. The results show that the ornamentation characters of pollens, achenes and leaf cells prove to be very helpful. Ornamentation of pollens and achenes could be used to distinguish between the four morphological types. Micromorphological studies on achenes, pollens and leaves of Typha were found useful with respect to taxa differentiation, hence it provides a key to make distinctions between species orgroups of species

    Stomatal control of leaf fluxes of carbonyl sulfide and CO<sub>2</sub> in a <i>Typha</i> freshwater marsh

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    Carbonyl sulfide (COS) is an emerging tracer to constrain land photosynthesis at canopy to global scales, because leaf COS and CO2 uptake processes are linked through stomatal diffusion. The COS tracer approach requires knowledge of the concentration normalized ratio of COS uptake to photosynthesis, commonly known as the leaf relative uptake (LRU). LRU is known to increase under low light, but the environmental controls over LRU variability in the field are poorly understood due to scant leaf scale observations.Here we present the first direct observations of LRU responses to environmental variables in the field. We measured leaf COS and CO2 fluxes at a freshwater marsh in summer 2013. Daytime leaf COS and CO2 uptake showed similar peaks in the mid-morning and late afternoon separated by a prolonged midday depression, highlighting the common stomatal control on diffusion. At night, in contrast to CO2, COS uptake continued, indicating partially open stomata. LRU ratios showed a clear relationship with photosynthetically active radiation (PAR), converging to 1.0 at high PAR, while increasing sharply at low PAR. Daytime integrated LRU (calculated from daytime mean COS and CO2 uptake) ranged from 1 to 1.5, with a mean of 1.2 across the campaign, significantly lower than the previously reported laboratory mean value (∼ 1.6). Our results indicate two major determinants of LRU – light and vapor deficit. Light is the primary driver of LRU because CO2 assimilation capacity increases with light, while COS consumption capacity does not. Superimposed upon the light response is a secondary effect that high vapor deficit further reduces LRU, causing LRU minima to occur in the afternoon, not at noon. The partial stomatal closure induced by high vapor deficit suppresses COS uptake more strongly than CO2 uptake because stomatal resistance is a more dominant component in the total resistance of COS. Using stomatal conductance estimates, we show that LRU variability can be explained in terms of different patterns of stomatal vs. internal limitations on COS and CO2 uptake. Our findings illustrate the stomata-driven coupling of COS and CO2 uptake during the most photosynthetically active period in the field and provide an in situ characterization of LRU – a key parameter required for the use of COS as a photosynthetic tracer

    Untersuchungen zur Renaturierung von Feuchtgebieten im Tijuana Ästuar unter besonderer Berücksichtigung von brackwasserhaltigen und salinen Teichen

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    This study represents the first comprehensive biological and hydrochemical investigation of small coastal ponds in the saltmarsh dominated Tijuana Estuary, southern California (U.S.). Special attention is given to the brackish water biotopes. Different salinities and considerable fluctuations in water level characterized these shallow ponds and restrict the biological settlement. Fluctuations of salinities ranged from brackish water to hyperhaline water conditions. Due to different salinity levels, the ponds vary in hydrochemistry, macroinvertebrate species composition and plant communities. The macroinvertebrate community of the brackish waters were dominated by Gastropoda, Odonata, and Coleoptera containing a mixture of freshwater/brackish water species and marine macroinvertebrates. Typical plants of the brackish habitat were Typha domingensis (Southern cattail), and Scirpus californicus (California bulrush) associated with Juncus acutus (Siny rush). These brackish habitats with a wide range of salinity fluctuations are sparsely colonized but represent a niche for typical highly adaptable species. Especially, it is a biotope for species with a wide range of salt tolerance. Therefore, endangered species occurred besides introduced or invasive species in the ponds of the Tijuana Estuary. This fact has to be taken into account in case of wetland restoration. Due to the freshwater influence, the restoration of brackish habitats focuses on the problem of invasive species.Die vorliegende Arbeit befasst sich mit der Situation des Tijuana-River-Ästuars im Südwesten Kaliforniens und untersucht insbesondere Flachgewässer mit Brackwassercharakter. Verschiedene Salzgehalte und erhebliche Schwankungen der Wasserstände sind für diese Gewässer charakteristisch und limitieren die biologische Besiedelung. Die Unterschiede in der Salinität reichen dabei von Brackwasserbedingungen bis hin zur Hypersalinität. Aufgrund der verschiedenen Salzgehalte variieren die Gewässer in der hydrochemischen Zusammensetzung, der Makroinvertebratenzusammensetzung und der Pflanzengesellschaften. Die Gruppe der Makroinvertebraten in den Brackwasserbiotopen wird von Schnecken, Libellen und Käfern dominiert, wobei Süß- und Brackwasserarten zusammen mit marinen Invertebraten auftreten. Typische Pflanzen der Brackwasserlebensräume sind Typha domingensis und Scirpus californicus, verbunden mit Juncus acutus-Pflanzen. Solche Brackwasserbiotope mit ihren stark schwankenden Salzgehalten sind zwar artenarm, aber sie stellen zugleich Nischen für Organismen mit speziellem hohem Adaptationsvermögen insbesondere hinsichtlich der Salztoleranz dar. So wurden bei den Untersuchungen gefährdete, aber auch invasive Arten gefunden. Diese Besonderheit ist bei allen Sanierungs- und Renaturierungsaktivitäten zu berücksichtigen
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