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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.

Intensively managed grasslands are large sources of the potent greenhouse gas nitrous oxide (N2O) and important regulators of methane (CH4) consumption and production. The predicted increase in flooding frequency and severity due to climate change could increase N2O emissions and shift grasslands from a net CH4 sink to a source. Therefore, effective management strategies are critical for mitigating greenhouse gas emissions from flood-prone grasslands. We tested how repeated flooding affected the N2O and CH4 emissions from 11 different plant communities (Festuca arundinacea, Lolium perenne, Poa trivialis, and Trifolium repens in monoculture, 2- and 4-species mixtures), using intact soil cores from an 18-month old grassland field experiment in a 4-month greenhouse experiment. To elucidate potential underlying mechanisms, we related plant functional traits to cumulative N2O and CH4 emissions. We hypothesized that traits related with fast nitrogen uptake and growth would lower N2O and CH4 emissions in ambient (non-flooded) conditions, and that traits related to tissue toughness would lower N2O and CH4 emissions in flooded conditions. We found that flooding increased cumulative N2O emissions by 97 fold and cumulative CH4 emissions by 1.6 fold on average. Plant community composition mediated the flood-induced increase in N2O emissions. In flooded conditions, increasing abundance of the grass F. arundinacea was related with lower N2O emissions; whereas increases in abundance of the legume T. repens resulted in higher N2O emissions. In non-flooded conditions, N2O emissions were not clearly mediated by plant traits related with nitrogen uptake or biomass production. In flooded conditions, plant communities with high root carbon to nitrogen ratio were related with lower cumulative N2O emissions, and a lower global warming potential (CO2 equivalent of N2O and CH4). We conclude that plant functional traits related to slower decomposition and nitrogen mineralization could play a significant role in mitigating N2O emissions in flooded grasslands.

Introduction . There is a great deal of researches on the effects of S. canadensis L. on species of phytocenoses and biodiversity in general, however the results of such researches have many contradictions. They differ depending on their research locations . This proves that the behavior of S. canadensis L. in phytocenoses is highly dependent on many factors (soil, climate, species composition of local phytocenoses ) as well as the lack of a clear understanding of the mechanisms of its impact on phytocenoses, indicating the need to further study the impact of this species on phytocenoses to understand this mechanism. Purpose. The detection of S. canadensis L . localities in the Cherkasy urban ecosystem, study of synecological parameters of S. canadensis L. and accompanying species, as well as its influence on the floristic composition of phytocenoses; predicting the possibility of further increasing the invasion area and identifying priority areas for measures to control it. Methods. Locations were searched using the route method. The accounting was carried out at accounting sites of 1 m 2 , using standard geobotanical techniques. Statistical processing of the results was performed using dispersion coefficient, diversity compositioт coefficient, occurrence coefficient, Jaccard similarity coefficient and cluster analysis by nearest neighbor method. Results. In the course of the research conducted during the vegetation period 2016-2017, a significant level of presence of the S. canadensis L . was noted in 9 districts in Cherkasy: average projective coverage of 20,00% - 82 , 67%. S. canadensis L . dominates on 74% of the accounting sites. In all districts depletion of the species composition of spontaneous plant communities due to the invasion of the S. canadensis L. was found: the average number of species per 1 m 2 was 6.68 ± 0.23 species. The occurrence coefficients of the accompanying species are calculated, the species occurring in phytocenoses with S. canadensis L . are most often identified: Elymus repens (L.) Gould (76%) Ambrosia artemisiifolia L . (64%) Achillea submillefolium Klok. et Krytzka (50%) Stenactis annua (L.) Cass. ex Less. (36%) Acer negundo L. (30%) Sonchus arvensis L. (26%) Poa trivialis L . (20%) Trifolium pratense L . (18%) Artemisia absinthium L. (16%) Trifolium arvense L . (16%), Artemisia vulgaris L. (14%). In comparing the species composition of the phytocenoses of the 9 districts by Jaccard similarity coefficient and the cluster analysis of the average projective coverage of the S. canadensis L. and accompanying species, priority areas were identified to control the invasion of the S. canadensis L . Combining cluster analysis with Jaccard similarity coefficient increases the accuracy of the results (because the species composition of the phytocenoses in addition to their quantitative indicators is taken into account). Similar invasion behavior is predicted in areas with similar species composition of phytocenoses. Conclusion. S. canadensis L . was detected in 9 Cherkasy districts. Negative influence of the S. canadensis L . on the species composition of phytocenoses has been proved. The species that were found most often with the S. canadensis L . have adapted to the conditions it creates. The combination of Jaccard similarity coefficient and cluster analysis yields more accurate results than cluster analysis alone.

SUMMARY Miniswards of Lolium perenne, Festuca rubra, Agrostis casteUana and Poa trivialis were grown in a sand-limestone mixture and fed with a complete nutrient solution containing 3 mol m−3 NH4NO3. The miniswards were cut weekly to a height of 4 cm until a steady state of growth, based on weight of clippings removed, was achieved. After clipping (day 0) the nutrient solution was replaced by one in which all the nitrogen (N) was enriched with 15N to 5 atom per cent, but was otherwise identical. This allowed discrimination of remobilization from current root uptake when considering the supply of N for regrowth of laminae. Destructive harvests were made over the following 28-d period, while unharvested plants continued to receive a weekly clip. The proportion of the total uptake of labelled N which appeared in the clipped material was of the order L. perenne > P. trivialis > A. castellana > F. rubra. The change in unlabelled N in the roots plus leaf bases over time was modelled as a proportion of the amount present on day 0. A simple exponential model with a non-zero asymptote was found to model the data; the asymptote was assumed to represent the proportion of unlabelled N not readily available for remobilization. Species differences in the asymptotes were found, with F. rubra having a significantly larger asymptote than A. castellana and P. trivialis, which in turn both had significantly larger asymptotes than L. perenne. All species used both root uptake and remobilization to supply N for post-defoliation regrowth of laminae. However, the relative contribution of each source was species-dependent. The proportion of N in the clipped material derived from remobilization was significantly greater for F. rubra than A. castellana, which in turn had a significantly greater proportion derived from remobilization than P. trivialis and L. perenne.

International audience; High throughput sequencing was performed on virion-associated nucleic acids (VANA) from a pool of fifty asymptomatic rough bluegrasses (Poa trivialis L.) collected in a Belgian grazed pasture. Bioinformatics analyses produced some contigs presenting similarities with secovirid genomes, in particular nepoviruses and waikaviruses. Three distinct positive-sense single-stranded RNAs including 5? and 3? UTR were reconstructed and they represented two novel viruses infecting rough bluegrass, for which the provisional names poaceae Liege nepovirus A (PoLNVA, 7298 nt for RNA1 and 4263 nt for RNA2) and poaceae Liege virus 1 (PoLV1, 11,623 nt) were proposed. Compared to other Secoviridae members, the highest amino acid identity reached 90.7 % and 66.7 % between PoLNVA and nepoviruses for the Pro-Pol and CP regions respectively, while PoLV1 presented the highest amino acid identity with waikaviruses but with lower identities, i.e. 41.2 % for Pro-Pol and 25.8 % for CP regions, far below the ICTV demarcation criteria for novel secovirid. Based on sequence identity and phylogenetic analyses, PoLNVA was proposed to belong to the genus Nepovirus and PoLV1 as an unclassified secovirids. Detection of the two novel viruses was confirmed in high prevalence in rough bluegrass and ten other wild Poaceae species (Agropyron repens, Agrostis capillaris, Apera spica-venti, Anthoxanthum odoratum, Cynosorus cristatus, Festuca rubra, Holcus lanatus, Lolium perenne, Phleum bertolini and Phleum pratense) by RT-PCR and Sanger sequencing, revealing a diverse host range within Poaceae for these novel secovirids. Seed transmission was evaluated and confirmed for PoLNVA.

The increasing frequency of extreme weather events, such as floods, requires management strategies that promote resilience of grassland productivity. Mixtures of plant species may better resist and recover from flooding than monocultures, as they could combine species with stress-coping and resource acquisition traits. This has not yet been tested in intensively managed grasslands despite its relevance for enhancing agroecosystem resilience. Using intact soil cores from an 18-month-old field experiment, we tested how 11 plant communities (Festuca arundinacea, Lolium perenne, Poa trivialis and Trifolium repens in monoculture, two- and four-species mixtures) resist and recover from repeated flooding in a 4-month greenhouse experiment. We found that plant community composition, not whether the community was a mixture or monoculture, influenced the community's resistance to flooding, although most communities were able to resist and recover from both floods. The plant community's position on the leaf economic spectrum in flooded conditions was related to its resistance to and recovery from flooding. Resistance to and recovery from a severe flood were related to flood-induced intraspecific trait variation, causing a shift in the community's position on the leaf resource economic spectrum. In flooded conditions, resource-conservative communities (characterized by low specific leaf area, low leaf nitrogen content and high leaf dry matter content) better resisted and recovered from flooding. The community's position on the root resource economic spectrum was less connected to the community's resistance and recovery. Synthesis and applications. Our study shows that in flooded conditions, resource-conservative plant communities are more resilient to flooding than resource-acquisitive communities in an intensively managed grassland. This suggests that plant community position on the leaf economic spectrum, as well as species’ flood-induced intraspecific variation, should be considered when designing grasslands to withstand increasing flood frequency and severity.

Halotropism is a form of adaptive directional growth in which roots grow away from areas of high salt concentrations. Halotropism is thought to function in cooperation with the more well-understood mechanisms of ion exclusion and sequestration to mediate salt tolerance. Halotropic growth is dependent upon precisely regulated changes in auxin transport and metabolism. As both of these processes have been demonstrated to be modulated by flavonoid accumulation, it is likely that flavonoids serve a regulatory role in halotropism. The objectives of this study were first to determine if the flavonoid hyper-accumulating turfgrass species rough bluegrass (Poa trivialis L.) exhibits halotropism, and, second, to investigate the impact of light-induced flavonoid accumulations on root halotropic bending responses. Results showed that rough bluegrass grown in an agar system under white light exhibits halotropic root growth when treated with salt gradients created by concentrations of NaCl greater than 300 mM. In the dark or with red light treatment, rough bluegrass did not exhibit halotropism, but when treated with blue light, halotropic growth was enhanced compared to white light treatment. Metabolomic analysis showed that flavonoids only accumulated in roots at levels above the limit of detection when plants were exposed to blue or white light. Altogether, results showed that rough bluegrass exhibits halotropism that correlates with light-induced accumulations of flavonoids.

Oregon's Willamette Valley is the major cool-season, grass-seed-production area in the world. Roughstalk bluegrass (RB) is a weed in waterlogged, grass-seed-crop fields. Growth chamber and greenhouse studies were conducted to determine the influence of waterlogging on the germination and establishment of RB and tall fescue (TF). Oxygen deficiency resulted in a germination delay in both species, but was greater for TF. Oxygen deficiency at 20 and 30 C was greater for TF compared to RB. Simulated waterlogging for 28 d reduced aboveground biomass more for RB (58 %) than for TF (46 %), but did not influence seedling survival. Compared to TF, the influence of waterlogging on RB was greater during early establishment. These responses may help RB maintain its germination rate while reducing the damage caused by the accumulation of toxic fermentation-metabolites during waterlogging which benefits RB in competition with TF, especially under high temperatures.Nomenclature: Roughstalk bluegrass, Poa trivialis L.; tall fescue, Lolium arundinaceum (Schreb.) S.J. Darbyshire.

Sheep landraces are an invigorating element in terms of the biodiversity of the cultural landscape. The present study focused on the question of whether the Bentheimer Landschaf breed, which is a representative of a large sheep landrace, is equally as well-suited for the maintenance of extensively farmed fen grassland as the smaller, hardy Skudde breed of sheep. For each breed, two flocks with 10 ewes and their lambs were included in a 3-year grazing trial on long-standing, extensively used fen grassland paddocks. Our study revealed no major differences between Skudde and Bentheimer Landschaf regarding feed preference, endozoochorous dispersal potential and reproductive performance. The food intake of both breeds was not only limited to high-quality forage grasses, they also chose more crude fiber-rich plant species. Reed canary grass (Phalaris arundinacea L.) was preferably selected. A relevant problem under set stocking conditions with alternate hay cutting was the spread of creeping thistle (Cirsium arvense (L.) Scop.) on the paddocks of both sheep breeds. The majority of the germinable seeds found in fecal samples were contributed by the small-seeded grass species Poa trivialis L. and Agrostis stolonifera L., which were the most abundant in the vegetation of the paddocks. Juncus spp. seeds were found at above-average levels in the fecal samples compared with the vegetation percentages of these species. Among the weed species, only stinging nettle (Urtica dioica L.) showed a higher endozoochorous dispersal potential. The greater slaughter weight of Bentheimer Landschaf lambs has a positive effect on the efficiency of sheep farming. Considering all of the studied characteristics, we concluded that large landrace Bentheimer Landschaf sheep as well as Skudde sheep may be only recommended for the maintenance of drained fen grassland if additional control strategies against the spread of thistles accompany grazing management.

A Labyrinthula sp. was isolated from symptomatic rough bluegrass (Poa trivialis L.) and perennial ryegrass (Lolium perenne L.) from a golf course in Arizona. Initial symptoms were a water-soaked appearance and rapid collapse of small patches of turf foliage. The affected turf died, and patches coalesced to form large dead areas after several weeks. The symptoms were those of the disease recently termed “rapid blight” for which the causal agent has not been identified (1). Rapid blight was first observed in southern California in 1995 and has become increasingly problematic in 10 other states on several cool-season turfgrasses (1). In Arizona, it is associated with high salinity irrigation water. In microscopic examinations of symptomatic P. trivialis and L. perenne leaf tissue from November 2002 to February 2003, fusiform or spindle-shaped vegetative cells (4 to 5 × 15 to 20 μm) were observed in leaf cells. These cells are consistently associated with rapid blight (1) and are typical in size and shape of those described for Labyrinthula spp. (3,4). The fusiform cells were cultured in 1% horse serum water agar medium made with irrigation water (electrical conductivity [EC] = 3.5 to 4.0 dS/m) from a golf course in central Arizona with rapid blight. The cells readily formed colonies on this medium and exhibited gliding motility along a network of hyaline slime filaments as previously described for the genus Labyrinthula (3,4). Koch's postulates were fulfilled by inoculating P. trivialis and L. perenne seedlings with Labyrinthula sp. isolated from naturally infested P. trivialis in two experiments. The grasses were started from seed and grown as a lawn in containers in the laboratory. Both experiments were repeated once. In the first experiment, infested autoclaved leaf pieces of P. trivialis were used as inoculum. Inoculated leaf pieces were placed within each of several bundles of 4 to 6 leaves and held loosely in place with a 0.5-cm wide ring of tygon tubing. Seedlings were irrigated with sterilized irrigation water from the golf course (EC = 4.0 dS/m). In the second experiment, agar discs from Labyrinthula sp. colonies on 1% horse serum agar were used as inoculum by placing the agar discs in contact with leaves. Seedlings were irrigated with sterile tap water adjusted to 4.0 dS/m using synthetic sea salt (Instant Ocean, Aquarium Systems, Inc., Mentor, OH) Leaf tissue of all inoculated seedlings became water soaked within 3 to 7 days and collapsed within 10 days in both experiments. Fusiform cells were observed in inoculated leaf tissue cells, and the Labyrinthula sp. was reisolated from 100% of selected symptomatic seedlings. Control seedlings treated with noninfested leaf pieces or sterile agar pieces did not develop symptoms, and no fusiform cells were isolated from the leaf tissue. Labyrinthula spp. are usually associated with marine systems (3). Labyrinthula zosterae D. Porter & Muehlst. has been identified as the causal agent in a marine grass wasting disease (2), but to our knowledge, no Labyrinthula spp. have been described as pathogens of terrestrial plants. References: (1) S. B. Martin et al. Phytopathology (Abstr.) 92:(suppl)S52, 2002. (2) L. K. Muehlstein et al. Mycologia 83:180, 1991. (3) K. S. Porkorny. J. Protozool. 14:697, 1967. (4) D. Porter. Handbook of Protoctista. Jones and Bartlett, Boston, MA, 1990.

Pythium spp. were isolated from nonoverseeded bermudagrass and from bermudagrass overseeded with cool-season turfgrass species from October 2000 to July 2001 from two sites in Florida. Pythium spp. were isolated from nonoverseeded and overseeded, and fumigated and nonfumigated, bermudagrass plots from October 2001 to July 2002 from one of the two sites. The vast majority of isolates of Pythium spp. were obtained from the bermudagrass, rather than the cool-season turfgrass species (Poa trivialis or Lolium perenne) used as overseed. In the first year at the Ft. Lauderdale site, Pythium graminicola dominated (91% of isolates obtained). In the first year at the Gainesville site, P. graminicola (56% of isolates) and P. irregulare (36%) dominated; however, after fumigation and replanting, P. graminicola comprised only 11% of all isolates. P. irregulare comprised 30% of all isolates, but was found only in nonfumigated plots. A different species, P. ultimum var. ultimum, not isolated in the first year, was recovered (34% of isolates) from the replanted field in February and March. In preemergence pathogenicity tests, three of four isolates of P. irregulare were moderately to highly pathogenic on Poa trivialis, but not on L. perenne, and isolates of Pythium graminicola and P. ultimum var. ultimum were not pathogenic on either turfgrass species. Pathogenic Pythium spp. may survive from season to season on bermudagrass and, under favorable conditions, may cause damping-off or blight on the overseeded cool-season turfgrass.

Brown ring patch is a newly described disease of cool-season turfgrass first reported in Japan on creeping bentgrass (Agrostis palustris) (2) and later reported in California on annual bluegrass (Poa annua) (1). The disease is characterized by either patches or rings of discolored to blighted turfgrass that can range from a few centimeters to a meter in diameter. Affected turfgrass plants turn chlorotic and can be blighted from the crown to the leaf tips. Blight symptoms have been associated with fluffy white-to-cream aerial mycelium after extended incubation of the sample. Symptoms including patches of blighted turfgrass approximately 10 cm in diameter were observed on roughstalk bluegrass (Poa trivialis) that had been overseeded onto a dormant ‘Tifdwarf’ bermudagrass (Cynodon dactylon) putting green in Palatka, FL. A sample was submitted by the superintendent in June 2005 because symptoms were confused with dollar spot and a fungicide resistance issue was suspected. The sample produced abundant aerial mycelium after incubation. The pathogen was isolated on potato dextrose agar amended with rifampicin (100 ppm) and streptomycin (100 ppm) from Poa plants surface disinfested with 70% ethanol for 30 s. Colony and sclerotia morphology were consistent with Waitea circinata var. circinata as previously described (1,2). The teleomorph W. circinata var. circinata was not observed on plant material or culture plates. Amplified fragments of rDNA including internal transcribed spacers from the isolate were sequenced bidirectionally from four bacterial clones. The consensus sequences (GenBank Accession Nos. FJ029103, FJ029104, FJ029105, and FJ029106) matched with 99% homology (99% sequence overlap) isolate TRGC1.1 of W. circinata var. circinata described by Wong, NCBI Accession No. DQ900586 (1). Pots of ‘Cypress’ roughstalk bluegrass that were 1 week postemergence were inoculated with the pathogen using 10 infested wheat grains. Plants were incubated at 25°C in a sealed plastic bag with a moist paper towel in the bottom. Hyphae grew from the grains and colonized the grass. Individual plants began to turn chlorotic within 3 days and greater than 90% of the turf in pots was dead after 1 week. The fungus was reisolated from affected plants. Control pots were inoculated with uninfested wheat grains and showed no disease symptoms after 1 week. Inoculations were repeated twice more with the same results. To our knowledge, this is the first report of brown ring patch on P. trivialis in Florida. References: (1) K. A. de la Cerda et al. Plant Dis. 91:791, 2007. (2) T. Toda et al. Plant Dis. 89:536, 2005.

International audience; Regrowth after defoliation is an essential mechanism of plant tolerance to grazing. In grasses, non-structural carbohydrates (NSC) contained in tiller bases constitute a major substrate for regrowth after defoliation. Using a multi-specific approach, the present study aimed at testing the effect of grazing intensity on NSC concentration in tiller bases. We selected five grazing-tolerant grass species (Agrostis stolonifera, Cynosurus cristatus, Hordeum secalinum, Lolium perenne and Poa trivialis) and collected plants in a grassland subjected to two cattle grazing intensities (intensive versus moderate) for years. We measured NSC concentrations (starch, fructans, sucrose, glucose and fructose) in tiller bases. We found that fructan and sucrose concentrations before the grazing season (April) were higher under intensive than moderate grazing. By contrast, no significant effect of the grazing intensity on these NSC concentrations in tiller bases remained at the end of the grazing season (October). These results suggest that the level of reserves available before the onset of disturbance caused by grazing as well as the reserve replenishment capacity during the grazing season are modified by the intensity of grazing.

Anthocyanins are plant pigments that are in demand for medicinal and industrial uses. However, anthocyanin production is limited due to the harvest potential of the species currently used as anthocyanin sources. Rough bluegrass (Poa trivialis L.) is a perennial turfgrass known for accumulating anthocyanins, and may have the potential to serve as a source of anthocyanins through artificial light treatments. The objectives of this research were to determine optimal light conditions that favor anthocyanin synthesis in rough bluegrass, and to determine the suitability of rough bluegrass as a source of anthocyanins. When exposed to high-intensity white light, rough bluegrass increased anthocyanin content by 100-fold on average, and anthocyanin contents greater than 0.2% of dry tissue weight were observed in some samples. Blue light, at intensities between 150 and 250 μmol·m−2·s−1, was the only wavelength that increased anthocyanin content. However, when red light was applied with blue light at 30% or 50% of the total light intensity, anthocyanin content was increased compared with blue light alone. Further experiments demonstrated that these results may be potentially due to a combination of photosynthetic and photoreceptor-mediated regulation. Rough bluegrass is an attractive anthocyanin production system, since leaf tissue can be harvested while preserving meristematic tissues that allow new leaves to rapidly grow; thereby allowing multiple harvests in a single growing season and greater anthocyanin yields.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous, obligatory plant symbionts that have a beneficial influence on plants in contaminated environments. This study focused on evaluating the biomass and biodiversity of the AMF and microbial communities associated with Poa trivialis and Phragmites australis plants sampled at an aged site contaminated with phenol and polynuclear aromatic hydrocarbons (PAHs) and an uncontaminated control site. We analyzed the soil phospholipid fatty acid profile to describe the general structure of microbial communities. PCR-denaturing gradient gel electrophoresis with primers targeting the 18S ribosomal RNA gene was used to characterize the biodiversity of the AMF communities and identify dominant AMF species associated with the host plants in the polluted and control environments. The root mycorrhizal colonization and AMF biomass in the soil were negatively affected by the presence of PAHs and phenol, with no significant differences between the studied plant species, whereas the biodiversity of the AMF communities were influenced by the soil contamination and plant species. Soil contamination was more detrimental to the biodiversity of AMF communities associated with Ph. australis, compared to P. trivialis. Both species favored the development of different AMF species, which might be related to the specific features of their different root systems and soil microbial communities. The contaminated site was dominated by AMF generalists like Funneliformis and Rhizophagus, whereas in the control site Dominikia, Archaeospora, Claroideoglomus, Glomus, and Diversispora were also detected.

Rumex obtusifolius is a troublesome weed especially in organically managed grasslands. Manual weeding is commonly used for R. obtusifolius control, but its effectiveness and effect on plant species composition in upland grassland has never been investigated. Therefore the aim of our study was to reveal the effect of manual weeding by digging out R. obtusifolius taproots to depths of 5 or 15 cm, either once or twice, in: (i) presence of R. obtusifolius plants; (ii) plant species composition. Additional treatments were grazed and unmanaged grassland (both without digging out R. obtusifolius taproot). Digging out taproots twice, to 15 cm, reduced the presence of R. obtusifolius significantly. Grazing without digging out taproots was the treatment that was most favourable for R. obtusifolius plants. Manual weeding had no significant effect on species richness. The empty spaces after plant removal were filled by nutrient-demanding species (Poa pratensis, Poa trivialis, Festuca pratensis and Lolium perenne, Trifolium repens and Taraxacum sp.). On unmanaged grassland the number of R. obtusifolius plants decreased, species richness was reduced, but this allowed the spread of other tall weedy species (Urtica dioica, Galium album and Elytrigia repens). Digging out taproots to a depth of 15 cm, performed twice, can be an effective method for R. obtusifolius control in organically managed grasslands, as this procedure eliminated the majority of R. obtusifolius plants. However, the use of this weeding method over large areas of grassland is limited due to time-consuming and hard physical work.

Variability of some morphological characters of Festuca pratensis, Alopecurus pratensix and Poa tririalis was determined. The blades and ligules show the highest variability in contrast to the small variability of the length of inflorescences. It exists a clear relationship between height of generative shoots soil's moisture. Correlations between some morphological characters were established.

Dormant bermudagrass (Cynodon dactlyon (L.) Pers. × C. transvaalensis Burtt-Davy) is overseeded with perennial ryegrass (Lolium perenne L.) to maintain green color through the fall and winter. Annual bluegrass (Poa annua L.) control is critical for overseeding success, as this weed can greatly decrease aesthetic quality and playability of turfgrass due to excessive seedhead production. Research was conducted to evaluate the influence of pre-seeding cultural practices (scalping, solid-tine aerification, vertical mowing, and vertical mowing plus scalping) on overseeding establishment. The effect of increasing overseeding rates of perennial ryegrass (111, 222, 444, and 888 kg pure live seed·ha−1; 100, 200, 400, and 800 lb·A−1) and roughstalk bluegrass (Poa trivialis L.) (55, 111, and 222 kg pure live seed·ha−1; 50, 100, and 200 lb·A−1) on annual bluegrass populations was also investigated. Additionally, plant growth regulators (PGRs) were evaluated for annual bluegrass seedhead suppression and turf injury. Mefluidide at 0.056 kg ae·ha−1 (0.05 lb ae·A−1), and paclobutrazol, flurprimidol, trinexapac-ethyl, and trinexapac-ethyl plus ethephon at 0.28, 0.42, 0.382, and 0.095 plus 3.82 kg ai·ha−1 (0.25, 0.37, 0.34, 0.085 plus 3.4 lb ai·A−1), respectively, were applied twice, sequentially with a four-week interval. Contrary to previous research, pre-seeding cultural practices did not improve overseeding success. Annual bluegrass density decreased with increasing perennial ryegrass overseeding rates from 50% in the non-overseeded to 14 to 17% when overseeded with rates up to 222 kg pure live seed·ha−1, and 4 to 8% when overseeded with rates between 444 and 888 kg pure live seed·ha−1. Roughstalk bluegrass overseeded reduced annual bluegrass density from 50% in the non-overseeded, to 7 to 13% when overseeded with 55, 111, or 222 kg pure live seed·ha−1, regardless of the overseeding rate. Overseeding bermudagrass with roughstalk bluegrass or perennial ryegrass increased turfgrass green cover during winter, especially 100 days after seeding. Paclobutrazol, flurprimidol, and trinexapac-ethyl were successful at suppressing annual bluegrass seedheads and were not injurious to perennial ryegrass. Mefluidide resulted in efficient annual bluegrass seedhead suppression; however, unacceptable turfgrass injury occurred in 2012.

Tolerance of four cool-season turfgrass species sheep fescue (Festuca ovina), perennial ryegrass (Lolium perenne), colonial bentgrass (Agrostis tenuis) and rough bluegrass (Poa trivialis) to SO2 was studied by investigating their injury and physiological responses under SO2 stress for 14 days. Results showed that sheep fescue and perennial ryegrass had better SO2 tolerance than rough bluegrass and colonial bentgrass. Chlorophyll a and carotenoid contents were significantly higher in the SO2-tolerant turfgrass species (sheep fescue and perennial ryegrass) than in the SO2-sensitive turfgrass species (rough bluegrass and colonial bentgrass). Relatively lower levels of reactive oxygen species (ROS), malondialdehyde, and electrolyte leakage (EL) were observed in SO2-tolerant turfgrass species. Gradually increased antioxidant enzyme activities and proline content in SO2-tolerant turfgrass species could counteract such damages and harmful effects caused by ROS and EL, respectively. Sulfite reductase played an im...

Roughstalk bluegrass (Poa trivialis) is a weed in cool season grass seed production fields in Oregon. Populations of this weed are often greater in fields prone to waterlogging. A greenhouse study was conducted to investigate the morphological and physiological differences between recently established roughstalk bluegrass and tall fescue (Lolium arundinaceum) plants in response to simulated waterlogging. Differences in root morphological development and root respiration were found between waterlogged tall fescue and roughstalk bluegrass. Plants after 4 weeks of waterlogging, leaf number, plant height, and root biomass were reduced more in tall fescue than in roughstalk bluegrass plants. The root length increased 6% in waterlogged tall fescue plants, and decreased 42% in waterlogged roughstalk bluegrass plants, which lead to a shallower root system in roughstalk bluegrass. Root aerenchyma area increased more in waterlogged roughstalk bluegrass than in tall fescue. Alcohol dehydrogenase and lactate dehydrogenase activities increased in the roots of both species, but not in the leaves. The increases were greater in tall fescue than in roughstalk bluegrass. Turf quality, aboveground biomass, photosynthetic capacity, and water-soluble carbohydrate concentrations were reduced by waterlogging, but there were no differences over time or species. Thus, the shallower root system, larger aerenchyma, and reduced fermentation rates were the characteristics most likely to contribute to better waterlogging tolerance in roughstalk bluegrass compared to tall fescue and invasion of roughstalk bluegrass in waterlogged cool season grass seed fields.

The author has found Puccinia asteris-olpini on Aster alpinus - a species new to Poland, and five species of fungi on host new to Poland: Anthracoidea caricis on Carer pallescens, Entyloma doctylidis on Dactylis glomerata, Schizonella melanogramma on Carex ornithopoda, Urocystis poae on Poa trivialis, Ustilago striiformis on Agropyron repens and Sesleria coerulea. Other species are rare in Polish mycoflora and known only from isolated stands.

Heat stress is a major limiting factor for the growth of cool-season turfgrass species. The objective of this study was to compare growth and physiological responses to heat stress between annual and perennial cool-season grass species. Two annual grass species, annual ryegrass ( Lolium multiflorum , cv. ‘Panterra’) and annual bluegrass ( Poa annua , ecotype ‘Njpl’) and two perennial grass species, perennial ryegrass ( Lolium perenne , cv. ‘Premier’) and rough bluegrass ( Poa trivialis , cv. ‘Sabre’) were exposed to three temperature regimes in growth chambers: optimal temperature control (20/15 °C day/night), moderate heat stress (10 °C above the control), and severe heat stress (20 °C above the control). Moderate heat stress did not cause significant physiological damages in any of the four grass species. Severe heat stress caused significant decline in turf quality (TQ), leaf relative water content (RWC), antioxidant enzyme (catalase) activity, membrane stability (EL), and resulted in severe membrane lipid peroxidation (MDA) in all four grass species. All these parameters in the two annual grass species were more responsive to severe heat stress, suggesting that the two annual species were less heat tolerant or more heat sensitive than the two perennial species. Differential heat responses between the two annual and two perennial grass species could be associated with the differences in the severity of leaf senescence, as manifested by TQ, EL, and MDA.

The present experiment, carried out in nine production fields of reed canary grass (Phalaris arundinacea) grown for energy purposes, evaluated the effect of plantation age on the occurrence and species composition of weeds. The selected plantations were divided into 3 groups that were conventionally called “young” (1–2 years old), “middle-aged” (3–5 years old), and “older” plantations (6–8 years old). Regardless of plantation age, altogether 43 species were found in the experimental fields. Moreover, 6 species were common for all the plantations and were found in them regardless of plantation age. The least species, only 18, were found on the “young” plantations, almost twice more on the “older” ones (30 species), whereas the largest spectrum of species was found in the “middle-aged” plantations (33 species). In the “young” plantations, annual weeds were the most common, with the highest constancy and coverage index found for Chenopodium album, Matricaria maritima ssp. inodora and Echinochloa crus-galli. The greatest variation in species was found in the “middle-aged” plantations. However, only 4 species achieved the highest constancy and coverage index: Matricaria maritima ssp. inodora, Cirsium arvense, Poa trivialis and Taraxacum officinale. Furthermore, perennial weeds were found to be dominant in the “older” plantations. Within this group, Poa trivialis, Taraxacum officinale, Urtica dioica, Plantago maior, and Cirsium arvense had the highest constancy and coverage index.

How light conditions affect development of park grasslands is a question that has not been satisfactory addressed. The aim of this study was therefore determination of the level to which unfavorable light conditions influence grassy parks area and relationships between parameters which determine state of turf grasses. Researches were conducted in two parks in Warsaw, in various light conditions and included measurement of: leaf density, sward height, leaf area index (LAI), and botanical composition of the communities. The leaf density of shaded areas did not exceed 70%. LAI value varied from 0.5 to 0.9-fold lower than in the areas in half-shade and in sun. The partici pation of basic lawn species at Skaryszewski Park was higher under shade, while at Łazienki Krolewskie was higher in full-sunlight areas. The state of tested grassy areas in limited solar radiation does not satisfy the requirements of recreational and representational functions. The development processes of vegetation coverage were inhibited at the sites of lower solar radiation. LAI was influenced by both leaf coverage and sward height. Agrostis stolonifera and Poa trivialis may be recommended to create grass areas under limited solar radiation.

The occurrence of different shoot forms in Dactylis glomerata L., Festuca arundinacea Schreb., Holcus lanatus L., Avena fatua L. and other grass species was observed in investigations on vegetative reproduction modes deviating from normal. The relationship between the morphological and anatomical structure of these shoots, depends on the grass species as well as on ecological and biotic factors. The anatomical structure of elongated vegetative tillers and pseudostolons as well as underground rooting stems regrowing in the soil approximates that of stolons in Poa trivialis L. Branching generative shoots show the same arrangement of tissues as that encountered in non-branching ones. Shoots with such a structure are resistant to bending and, therefore, their contact with the soil and rooting of aerial tillers meet, as a rule, with difficulties. All kinds of parental branching shoots under study, irrespective of whether they developed above or in the soil, are usually short lived, provided with sheaths and leaf blades, similarly as stolons. It was found that in many grass species different tillering forms occur generally in vegetative reproduction what would require a definition and unification of names of such differentiated shoots.

This paper presents a survey of grass weeds in grass seed crops in Denmark. The survey is based on an analysis of data from a database containing monitoring of grass weeds in the period from 2004 to 2009 on an acreage of approximately 400,000 ha. The survey is based on weed monitoring carried out during a mandatory field inspection of grass seed crops. All fields grown with grasses for seed production are monitored shortly before harvest at a time when the weeds present are a result of a combination of the cropping history of the field, competition from the crop and the weed control carried out in the field. The survey showed that Poa annua, Elytrigia repens and Poa trivialis were the three most frequent grass weeds in grass seed crops. Furthermore, Bromus hordeaceus, Bromus sterilis, P. trivialis and Vulpia spp. showed an increasing frequency in the study period. The perennial weed, E. repens, and Dactylis glomerata were the only important grass weeds with a declining frequency during the six years. Vulpia spp. has recently become a significant problem in red fescue for seed production, and a significant increased frequency was seen during the study period. However, the study also showed that Vulpia spp. is primarily a problem in red fescue crops established in the autumn, whereas spring establishment of red fescue almost solves the problem with this primarily autumn-germinating grass weed. This paper presents a survey of grass weeds in grass seed crops in Denmark. The survey is based on an analysis of data from a database containing monitoring of grass weeds in the period from 2004 to 2009 on an acreage of approximately 400,000 ha. The survey is based on weed monitoring carried out during a mandatory field inspection of grass seed crops. All fields grown with grasses for seed production are monitored shortly before harvest at a time when the weeds present are a result of a combination of the cropping history of the field, competition from the crop and the weed control carried out in the field. The survey showed that Poa annua, Elytrigia repens and Poa trivialis were the three most frequent grass weeds in grass seed crops. Furthermore, Bromus hordeaceus, Bromus sterilis, P. trivialis and Vulpia spp. showed an increasing frequency in the study period. The perennial weed, E. repens, and Dactylis glomerata were the only important grass weeds with a declining frequency during the six years. Vulpia spp. has recently become a significant problem in red fescue for seed production, and a significant increased frequency was seen during the study period. However, the study also showed that Vulpia spp. is primarily a problem in red fescue crops established in the autumn, whereas spring establishment of red fescue almost solves the problem with this primarily autumn-germinating grass weed.

Calcium silicate has been used to supply silicon (Si) as a plant nutrient for enhancing crop production and the suppression of turf diseases. Research was initiated to determine the effect of calcium silicate on silicon uptake, turf quality, and its residual activity in providing plant available Si in two turfgrass systems. During 2005 and 2006, calcium silicate (CaSi, 12% Si) was applied as a topdressing at eight rates ranging from 0 to 342 kg m−2 to a ‘Tifdwarf’ (Cynodon dactylon × C. transvaalensis Burtt Davy) green in the spring and to the same plots overseeded with ‘Wintergreen’ rough bluegrass (Poa trivialis L.) in the fall. At initiation of the study, dolomitic limestone and magnesium sulfate (MgSO4) was applied to equilibrate calcium across all treatments based on the highest rate of CaSi. Every 28 days, treatments were rated for turf quality and then harvested to determine Si accumulation. One month after applying CaSi in 2005, Si concentration in the leaf tissue of Tifdwarf had increased linearl...

BACKGROUND AND AIMS Despite the selective pressure slugs may exert on seedling recruitment there is a lack of information in this context within grassland restoration studies. Selective grazing is influenced by interspecific differences in acceptability. As part of a larger study of how slug-seedling interactions may influence upland hay meadow restoration, an assessment of relative acceptability is made for seedlings of meadow plants to the slug, Deroceras reticulatum. METHODS Slug feeding damage to seedling monocultures of 23 meadow species and Brassica napus was assessed in microcosms over 14 d. The severity and rate of damage incurred by each plant species was analysed with a generalized additive mixed model. Plant species were then ranked for their relative acceptability. KEY RESULTS Interspecific variation in relative acceptability suggested seedlings of meadow species form a hierarchy of acceptability to D. reticulatum. The four most acceptable species were Achillea millefolium and the grasses Holcus lanatus, Poa trivialis and Festuca rubra. Trifolium pratense was acceptable to D. reticulatum and was the second highest ranking forb species. The most unacceptable species were mainly forbs associated with the target grassland, and included Geranium sylvaticum, Rumex acetosa, Leontodon hispidus and the grass Anthoxanthum odoratum. A strong positive correlation was found for mean cumulative feeding damage and cumulative seedling mortality at day 14. CONCLUSIONS Highly unacceptable species to D. reticulatum are unlikely to be selectively grazed by slugs during the seedling recruitment phase, and were predominantly target restoration species. Seedlings of highly acceptable species may be less likely to survive slug herbivory and contribute to seedling recruitment at restoration sites. Selective slug herbivory, influenced by acceptability, may influence community-level processes if seedling recruitment and establishment of key functional species, such as T. pratense is reduced.

Invasive alien plants often occur in monospecific stands with high density in the invaded range. Production of bioactive secondary metabolites in such stands could have allelopathic effects on germination of native species. We tested this component of the novel weapon hypothesis for Heracleum mantegazzianum, a prominent invader in Europe, using seeds of 11 native herbs exposed to soil or soil extracts from invaded stands, moist seeds or seed extracts of H. mantegazzianum. There was no effect of the various treatments on germination of most species, while germination was reduced in Urtica dioica on invaded soil, in Poa trivialis with H. mantegazzianum seed extract, and negative effects of the essential oil bergapten were found in three species. In P. trivialis the results of the seed extract were not supported by the experiment with added seeds of the invasive plant. Thus, there is limited evidence for allelopathic effects of the invasive H. mantegazzianum on germination of co-occurring native herbs.

As causal agents of bacterial wilt in pastures and meadows, bacteria of the species Xanthomonas translucens are a serious issue in forage grass production. So far, only little is known about host-pathogen interactions at the molecular level and the lack of comprehensive genome data impeded targeted breeding strategies towards resistant forage grass cultivars. Here we announce the draft genome sequences of three grass-pathogenic Xanthomonas translucens pathotype strains, i.e. pv. arrhenatheri LMG 727, pv. poae LMG 728 and pv. phlei LMG 730 isolated from Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl (Switzerland), Poa trivialis L. (Switzerland) and Phleum pratense L. (Norway), respectively. The genomes of all three strains revealed a non-canonical type III secretion system and a set of 22 type III effectors as common virulence-related traits. Distinct inter-pathovar differences were observed for the lipopolysaccharide biosynthesis gene cluster and the presence of nonribosomal peptide synthetases.