Academic literature on the topic 'Agrostis tenuis'

There is considerable uncertainty that the traditional identification of bent grasses in south-eastern Australia as Agrostis capillaris L. (Syn. Agrostis tenuis Sibth.) is correct, due to a history of confusing nomenclature and mis-identification. Bent grass is considered a weed of pastures in the high-rainfall zone of south-eastern Australia and thus the correct identity of bent grass may have implications for its management and control. Populations of bent grass were sampled from 42 pastures in south-eastern Australia and Agrostis castellana Boiss. et Reuter, rather than A. capillaris, was found to be the dominant species of Agrostis in 33 out of 42 bent grass pastures sampled. Five of the nine pastures sampled in Tasmania contained A. capillaris as opposed to only 1 of the 33 pastures sampled in Victoria. Agrostis castellana had not been identified in Victoria or Tasmania prior to this work. Since A. castellana grows more vigorously by rhizomes than A. capillaris, control measures recommended for A. capillaris may not be relevant for bent grass pastures in south-eastern Australia. Ligule length, ligule width and width of lamina, measured to determine whether species of bent grass could be easily distinguished in the field, did not distinguish adequately between A. castellana and A. capillaris.

The gene flow between populations of <em>Agrostis tennis</em> L. and <em>Festuca rubra</em> L. on a Zn/Pb mine and adjacent areas, which met at a distance of 150 m from the mine boundaries, was studied. It was found that the mine populations exhibit a high index of tolerance to Zn and Pb, elements encountered in the soil. Those outside the mine show relatively high indices of tolerance towards Zn and Pb, despite the fact that these elements are absent from the soil. On the other hand, the index of tolerance towards Cu, absent from the soil, of populations inside and outside the mine, was very low and did not differ from that of the control. Time difference in the flowering of these parapatric populations acts against gene flow thus resulting in a tendency for the neighbouring populations to isolate.

A number of seed, leaf, and stem gall nematodes are of significance to the forage and landscape grass and livestock industries. In North America, the bentgrass nematode, Anguina agrostis, reduces seed production on Agrostis tenuis and several other grass species. Anguina funesta is a seed-gall nematode that is most significant for its association with the toxigenic bacteria Rathayibacter toxicus. The wheat seed gall nematode A. tritici causes significant damage to wheat and other cereals; although it has been found in many countries worldwide, it has not been detected in the United States since 1975. Molecular methods based upon sequence variation in the ribosomal internal spacer region are useful for accurate identification of Anguina spp. Described herein are new species-specific primers and TaqMan probes for real-time polymerase chain reaction (PCR) identification of A. agrostis, A. funesta, A. tritici, and A. pacificae. Primer and probe combinations were each specific for the intended species and were sensitive enough to detect as few as 1.25 copies of nematode ribosomal DNA. PCR was also specific and sensitive in duplex assays that included genus-specific internal control primers as well as species-specific primers and probes. These standardized real-time PCR protocols should facilitate fast and accurate identification of Anguina spp. by diagnostic laboratories.

Evapotranspiration (ET) of three perennial ryegrass (Lolium perenne L.) cultivars and one cultivar each of colonial bentgrass (Agrostis tenuis L.) and tall fescue (Festuca arundinacea L.) was measured in the field. Soil water depletion was measured with a neutron probe. Under minimal maintenance (i.e., no irrigation and infrequent mowing), ET was not significantly different for five perennial grasses. All grasses used more water than the bare-ground treatment. Soil water uptake was greatest in the upper soil layer (O to 25 cm) and decreased with depth. Few differences in water uptake were noted among grasses within each soil layer.

Duplicate studies were conducted to determine salt tolerance during germination of eight bentgrass (Agrostis spp.) cultivars commonly used for overseeding warm-season turf species, such as bermudagrass (Cynodon spp.) putting surfaces. Bentgrass seeds were germinated on agar salinized with 0, 4000, 8000, 12,000, or 16,000 mg·liter-1, with the highest rate approaching one-half seawater salinity. Total germination decreased linearly or quadratically for specific cultivars as salinity increased. Time necessary to reach 50% germination across all salt concentrations was shortest for `Highland' colonial (Agrostis tenuis Sibth) and `Seaside' creeping (A. palustris Huds.) bentgrass (≈3.7 days); intermediate for `Kingstown' velvet (A. canina L.) and `Streaker' red top (A. alba L.) bentgrass (≈4.5 days); and longest for `Penneagle' creeping, `Penncross' creeping, `Exeter' colonial, and `Pennlinks' creeping bentgrass (≈5.3 days). Salt concentrations necessary to reduce germination to 90%, 75%, and 50% indicated that `Streaker' red top and `Seaside' creeping bentgrass were the most salt-tolerant cultivars. `Kingstown' velvet, `Exeter' colonial, and `Highland' colonial bentgrass were intermediate, while `Pennlinks', `Penncross', and `Penneagle' creeping bentgrass were the most salt-sensitive cultivars.

The aim of this study is to determine adaptation and quality parameters of some cool season turfgrass cultivars and species, In the scope of this study, leaf form, variation of leaf colour according to the seasons, tiller number, thinning ratio, weed ratio and general appearance of the species were determined. The experiment was established according to confounding design with four replications in Samsun Conditions at November, 2010. According to 1000 seed weight and characteristics of the plants seeding ratios were determined as pure and viable seed as follows; Lolium perenne 40 g m-2, Festuca rubra var. rubra and Festuca rubra var. commutata 30 g m-2, Festuca arundinacea 40 g m-2, Poa pratensis 20 g m-2, Festuca rubra trichophylla 30 g m-2, Agrostis stolonifera and Agrostis tenuis 5 g m-2, Festuca ovina 25 g m-2. According to the results obtained from this study it was determined that species/cultivars have some superiority to each other because of their different morphological and physiological characteristics. When we consider weed competition, Lolium perenne and Festuca arundinaceae cultivars have to be added to the mixture in order to decrease weed competition. There was colour variation distinctively depending on the seasons for all species. But, compare to the others, cultivars of Agrostis sp. and Poa pratensis cultivars have the potential to keep leaf colour in different seasons. Leaf form and appearance of Festuca rubra, Poa trivialis and Festuca ovina are better than the others. In order to keep good conditions of turfgrass areas, especially after cutting in summer period, Poa pratensis and Poa trivialis should added in mixtures to get benefit their higher regenerating power.

The present study continues a series of publications of the authors on diversity of the meadow vegetation in the floodplains of the Vychegda and Pechora rivers and their tributaries (Komi Republic). The floristic classification of wet meadows of the order Molinietalia Koch 1926 was published early (Shushpanikova, Yamalov, 2013). The results of floristic classification of meadow vegetation belonging to the order Arrhenatheretalia R. Tx. 1937 are discussed in this article. Analysis was based on 383 original relevés of the meadow vegetation of the order Arrhenatheretalia made in accordance with principles of the Braun-Blanquet approach (Braun-Blanquet, 1964; Mirkin and Naumova, 1998). The studies were performed in the floodplains of the Vychegda and Pechora rivers and their tributaries (Sysola, Kazhym, Pozheg, Viled, Usa, Colva, Synya, Sebys, Ilych, Syuzyu, Shchugor). The descriptions were conducted at the study plots of 10×10 m. Plant communities of small size were described within the natural limits. A location, dimensions of community, species composition, species saturation, composition of dominant and co-dominant species, total coverage and height of grass stand, aboveground phytomass production were identified. The abundance of species in meadow communities was recorded using the J. Braun-Blanquet method: r — species occurs sporadically, + — minor species, total coverage less than 1 %, 1 — 1–5 %, 2 — 6–25 % 3 — 26–50 %, 4 — 51–75 %, 5 — 76–100 %. The assessment of environmental parameters was performed by ecological methods of L. G. Ramensky (Ramensky et al., 1956). Syntaxonomic diversity of the meadow vegetation of the order Arrhenatheretalia of the Vychegda and Pechora rivers floodplains presented by 2 unions (Cynosurion R. Tx. 1947 и Festucion pratensis Sipaylova et al. 1985), 7 associations (Festucetum ovinae Turubanova 1986, Festuco pratensis–Deschampsietum caespitosae Turubanova 1986, Anthoxantho odorati–Agrostietum tenuis Sillinger 1933, Festuceto pratensis–Dactyletum glomeratae Dymina 1989 in Korolyuk et Kiprijanova 1998, Amorio repens–Poetum pratensis ass. nov., Equiseto arvensis–Elytrigietum repentis Maraculina 2009, Elytrigio repentis–Bromopsidetum inermis Yamalov 2011. Two new communities without rank are described (Agrostis vinealis, Hypericum maculatum–Phleum pratense). Most plant associations are heterogeneous by their floristic composition and they can be divided into 10 subassociations and 5 variants. The peculiarities of the floristic composition of the above mentioned associations, as well as their distribution and ecology are discussed. The distinguished associations are well differentiated by their elevation level on the floodplains. The meadow communities of Festucetum ovinae are located on the highest floodplains in the inland zone; there is Agrostis vinealis in the streamside zone of the floodplains. The meadow communities of the ass. Anthoxantho odorati–Agrostietum tenuis are located on the low floodplains in the streamside zone. The meadow communities of the associations Festuco pratensis–Deschampsietum caespitosae, Equiseto arvensis–Elytrigietum repentis, Elytrigio repentis–Bromopsidetum inermis, Festuceto pratensis–Dactyletum glomeratae are occupied the medium level floodplains. The meadow communities of the ass. Amorio repens–Poetum pratensis are found at different locations of the floodplain; they are formed under grazing. The described meadows grow on the soils with different ecological indicators. The distinguished associations are differentiated by water level (52.2–73.0), average figures — 55.9–68.9. The meadow communities of the ass. Festucetum ovinae occupy the driest sites of the floodplain; the ass. Anthoxantho odorati–Agrostietum tenuis is located in the wettest floodplains. The meadow communities of the ass. Elytrigio repentis–Bromopsidetum inermis occupy most rich and alluvial soils. They are located on the low ridges in the middle zone of the floodplain and they are formed by annual flooding on alluvial deposits. The distinguished associations are differentiated by pH (4.2–8.0), average figures — 4.9–7.0. The meadow communities with Agrostis vinealis are occupied the most acidic soil. The meadow communities of the ass. Anthoxantho odorati–Agrostietum tenuis are located on the neutral soils. The meadow communities of the most of associations occupy slightly acidic soils. The variability of moisture varies from alternating values to high values. The greatest differences in moisture are demonstrated by the communities of associations Equiseto arvensis–Elytrigietum repentis and Elytrigio repentis–Bromopsidetum inermis located on middle manes on low and medium levels of the floodplains. The associations are differ by the scale of pasture digression in range 3.3–5.0, average figures — 3.8–4.9. The meadow communities with Agrostis vinealis have the highest rates of pasture digression (4.5–5.1). The meadow communities of the ass. Anthoxantho odorati–Agrostietum tenuis have the smallest ones (3.5–3.9). A comparison of species composition of the syntaxa in Komi Republic with communities described in other regions of the Eastern Europe and the Asian part of Russia was carried out. It was shown that the meadow communities of the Komi Republic have low species diversity. Species richness of meadow communities is less than 39 species on trial area. The meadow communities of the ass. Festuco pratensis–Deschampsietum caespitosae are the richest. 195 vascular plant species are recorded in 213 geobotanical descriptions of the order Arrhenatheretalia. The aboveground phytomass varies from 20–40 g/m2 (Festucetum ovinae) to 520 g/m2 (Festuco pratensis–Deschampsietum caespitosae).

Le curage des sédiments des cours d'eau est nécessaire pour limiter les risques d'inondations et permettre la navigation fluviale. A cause des activités humaines, les sédiments de curage sont souvent contaminés en métaux, ce qui rend leur gestion problématique. Dans ce contexte,la phytostabilisation, une technique de traitement consistant à utiliser des plantes et des amendements minéraux pour réduire la mobilité des métaux dans des matrices solides contaminées, a été testée sur un sédiment de curage prélevé à proximité d'une fonderie de zinc et contaminé principalement par cet élément. Les plantes (Agrostis tenuis et Festuca rubra) ont été cultivées en serre, dans des mésocosmes d'environ 40 kg, qui contenaient l'un des trois substrats suivants : sédiment, sédiment + hydroxylapatite et sédiment + amendement sidérurgique ; des mésocosmes témoins non-végétalisés ont été placés dans les mêmes conditions. L'objectif principal de ce travail était de caractériser l'évolution de la spéciation du zinc induite par deux ans de phytostabilisation. Dans un premier temps, les associations géochimiques du zinc dans les différents milieux ont été observées sur des lames minces à l'échelle du micromètre grâce à l'utilisation combinée de techniques de micro-analyse (MEB-EDS, μXSRF). La spéciation du zinc dans chacune de ces associations a ensuite été déterminée par spectroscopie EXAFS résolue latéralement (μEXAFS). Le traitement des spectres μEXAFS par analyse en composantes principales (ACP) a permis l'identification de la sphalérite (ZnS), de la gahnite (ZnAl2O4) et de la franklinite (ZnFe2O4), qui sont des minéraux primaires certainement d'origine anthropique, et de la ferrihydrite (oxyhydroxyde de fer mal cristallisé) zincifère, d'une association zinc-phosphate, d'un phyllosilicate zincifère et de l'hydrotalcite (oxyhydroxyde d'aluminium) zincifère. Dans un second temps, les espèces zincifères ainsi identifiées ont été quantifiées à l'échelle macroscopique par spectroscopie EXAFS sur poudre. Les spectres EXAFS ainsi obtenus ont été simulés par combinaisons linéaires des spectres EXAFS des espèces zincifères précédemment identifiées, ce qui a permis d'évaluer l'effet du traitement sur la spéciation moyenne du zinc. En deux ans, elle a évolué de façon significative dans les mésocosmes amendés non-végétalisés, puisque l'on observe une diminution de la proportion de ZnS, la phase zincifère initialement majoritaire dans le sédiment, et la néoformation d'un phosphate de zinc. L'évolution de la spéciation du zinc est spectaculaire dans les mésocosmes végétalisés (amendés ou non), puisque dans ce cas, ZnS a été totalement oxydée et d'autres phases zincifères, telles qu'un phosphate de zinc et un phyllosilicate zincifère et / ou de l'hydrotalcite zincifère, se sont formées. La gahnite et la franklinite n'ont été observées qu'à l'échelle microscopique et sont donc des phases minoritaires. L'étude de la surface des racines des plantes par MEB-EDS, μSXRF et μEXAFS a permis de mettre en évidence la présence de précipités d'oxydes de manganèse (birnessite) riches en zinc, et parfois en plomb et en cuivre. Cette espèce chimique a été observée uniquement à la surface des racines et représente probablement une contribution minoritaire au processus global de l'immobilisation du zinc. Au bout de deux années, la phytostabilisation a permis la formation de phases zincifères plus stables que ZnS dans les conditions atmosphériques d'un dépôt de surface, indiquant que le zinc présent dans le sédiment phytostabilisé est potentiellement moins mobile que dans le sédiment seul. Ainsi, dans notre cas, la phytostabilisation limiterait donc la dispersion du zinc dans l'environnement.

L'arsenic est un métalloïde naturellement présent dans l'environnement, majoritairement sous formes inorganiques (arsenate (As(V) et arsenite (As(III) qui se trouvent être les plus toxiques pour les organismes vivants posant ainsi un réel problème de santé publique. Différentes méthodes de bio-réhabilitation des sols contaminés sont en cours de développement. Toutefois, la phytoremédiation, réhabilitation par les plantes, est complexe et les mécanismes de tolérance mis en place par les végétaux à la base du procédé ne sont pas vraiment élucidés. Ce travail a pour pour objectif de contribuer à la compréhension des mécanismes de toxicité et de tolérance chez différentes espèces dites sensibles et tolérantes. L'analyse d'un ensemble de paramètres physiologiques, biochimiques et protéomiques a été conduite chez 2 espèces annuelles cultivées (L. Esculentum et Z. Mays) et 2 espèces pérennes endémiques (A. Tenuis et D. Cespitosa) à travers différentes conditions de milieux hydroponiques arséniés (associant forme d'As (As(V) et As(III)), concentrations (134 et 668 µM) et pH (4-7 et 9). Une inhibition de paramètres de croissance (RRL, RFB, RDB) a été observée chez les quatre espèces, dépendantes des conditions de concentration et de forme d'As voire de valeur de pH du milieu. Toutefois, il est ressorti des résultats physiologiques de L. Esculentum un comportement de tolérance cararctérisé par une croissance maintenue et la stimulation du système enzymatique antioxydant. Ainsi, L. Esculentum montre une tolérance au stade de germination à la forme As(V) à pH9, non observée pour les autres espèces. D. Cespitosa, connue pour être une espèce tolérante hyperaccumulatrice de l'élément arsenic a montré un seuil de tolérance à cet élément fonction de la concentration. Les activités enzymatiques antioxydantes ne sont pas apparues systématiquement stimulées dans leur ensemble. Il ressort que la tolérance, dans la majorité des cas, ne concernerait qu'un pool d'enzymes, et non la totalité et serait variable selon les conditions de milieu, les espèces et organes. Il est intéressant aussi de souligner que l'espèce pérenne A. Tenuis (espèce pseudométallophyte accumulatrice) montre une utilisation limitée de ce type de mécanismes de défense bien que tolérante à une majorité des milieux arseniés étudiés, alors que D. Cespitosa fait largement appel à ce système enzymatique antioxydant avec un niveau de tolérance plus limité. Le protéome foliaire de A. Tenuis montre suite à l'exposition arseniée une fragmentation de protéines fonctionnelles (Oxygen-Evolving Enhancer protein, RuBisCO LSU et SSU, RuBisCo activase et ATP synthase) impliquées dans les processus respiratoires et photosynthétiques particulièrement la RuBisCO, illustrant une réorganisation métabolique de la plante. L'identification d'autres protéines foliaires suggère la probable implication de ces dernières dans les mécanismes de tolérance d'A. Tenuis à l'arsenic