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The inflorescence is composed of spikes, and the spike is the carrier of grass seed formation and development, so the development status of inflorescence implies grass seed yield and quality. So far, the systematic analysis of inflorescence development of Kentucky bluegrass has not been reported. The development process of the female gametophyte of wild germplasm materials of Kentucky bluegrass in Gannan, Gansu Province of China (KB-GN), was observed. Based on this, the key developmental stages of inflorescence in KB-GN were divided into premeiosis (GPreM), meiosis (GM), postmeiosis (GPostM), and anthesis (GA), and four stages of inflorescence were selected to analyze the transcriptome expression profile. We found that its sexual reproduction formed a polygonum-type embryo sac. Transcriptome analysis showed that 4256, 1125, 1699, and 3127 genes were highly expressed in GPreM, GM, GPostM, and GA, respectively. And a large number of transcription factors (TFs) such as MADS-box, MYB and NAC, AP2, C2H2, FAR1, B3, bHLH, WRKY, and TCP were highly expressed throughout the inflorescence development stages. KEGG enrichment and MapMan analysis showed that genes involved in plant hormone metabolism were also highly expressed at the entire stages of inflorescence development. However, a few TFs belong to stage-specific genes, such as TRAF proteins with unknown function in plants was screened firstly, which was specifically and highly expressed in the GPreM, indicating that TRAF may regulate the preparatory events of meiosis or be essential for the development of megaspore mother cell (MMC). The expression patterns of 15 MADS-box genes were analyzed by qRT-PCR, and the expression results were consistent with that of the transcriptome. The study on the inflorescence development of KB-GN will be great significant works and contribution to illustrate the basic mechanism of grass seeds formation and development. [ABSTRACT FROM AUTHOR]

The introduction of well-adapted species, such as Trifolium subterraneum (subclover) and Poa pratensis (Kentucky bluegrass), might enhance the forage yield and quality of dehesa pastures for feeding livestock. However, the climatic hardness and poor soils in these agrosystems may limit plant establishment and development. Since fungal endophytes have been found to alleviate the environmental stresses of their host, the aim of this study was to assess the effect of five isolates on forage yield, nutritive value, and plant mineral uptake after their inoculation in the two abovementioned plant species. Two experiments were established (under greenhouse and field conditions) using plants inoculated with two isolates in 2012/2013 (Epicoccum nigrum, Sporormiella intermedia) and three isolates in 2013/2014 (Mucor hiemalis, Fusarium equiseti, Byssochlamys spectabilis). Fusarium equiseti (E346) increased the herbage yield of T. subterraneum under greenhouse conditions, and B. spectabilis improved the forage quality of T. subterraneum by reducing fiber content and of P. pratensis by increasing crude protein. S. intermedia increased the mineral uptake of Ca, Cu, Mn, Pb, Tl, and Zn in subclover, and M. hiemalis increased the uptake of K and Sr in Kentucky bluegrass. These results evidence the potential of the studied fungal endophytes to enhance herbage yield and nutritional value of forage, although further studies should include all of the target forage species as certain host specificity in the effect was observed. [ABSTRACT FROM AUTHOR]

Drought stress occurs frequently and severely as a result of global climate change, and it exerts serious effects on plants. 5-Aminolevulinic acid (5-ALA) plays a crucial role in conferring abiotic stress tolerance in plants. To enhance the drought tolerance of turfgrass and investigate the effects of 5-ALA on antioxidant metabolism and gene expression under drought stress conditions, exogenous 5-ALA was applied by foliar spraying before Kentucky bluegrass ( Poa pratensis L.) seedlings were exposed to drought [induced by 10% polyethylene glycol (PEG)] stress for 20 days. 5-ALA pretreatment increased turf quality (TQ) and leaf relative water content (RWC) while reducing reactive oxygen species (ROS) production including HO content and O generation rate, lipoxygenase (LOX) activity, and malondialdehyde (MDA) content under drought stress. 5-ALA pretreatment maintained ascorbate (AsA) and glutathione (GSH) contents and the ASA/DHA and GSH/GSSG ratios at high levels, and it enhanced the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), dehydroascorbate reductase (DHAR), and glutathione reductase (GR), which are crucial for scavenging drought-induced ROS. In addition, 5-ALA upregulated the relative expression levels of Cu/ZnSOD, APX, GPX, and DHAR but downregulated those of CAT and GR under drought stress. These results indicated that the application of 5-ALA might improve turfgrass quality and promote drought tolerance in Kentucky bluegrass through reducing oxidative damage and increasing non-enzyme antioxidant levels and antioxidant enzyme activity at transcriptional and posttranscriptional levels. [ABSTRACT FROM AUTHOR]

Freezing stress, which can greatly reduce the growth, reproduction, and survival of plants, is predicted to increase for herbaceous species in northern temperate ecosystems as a result of climate change-induced reductions in snow cover. Increased N availability and elevated CO are other factors that may alter responses of plants to freezing, but studies regarding their interactive effects on the freezing tolerance of herbaceous plants are limited. We investigated the interactive effects of N and CO on the freezing stress response of the grass , Poa pratensis. Tillers were grown in controlled environment greenhouses in London, Ontario under ambient (400 ppm) or elevated (750 ppm) CO for 11 weeks in combination with low or high N fertilization. Tillers were then subjected to either 0, −2, −4, −6, −8, or −10 °C for 18 h (controls were harvested prior to freezing), and relative electrolyte leakage was measured to assess leaf freezing damage. We also determined leaf sucrose, glucose, and fructose concentrations before freezing, which helped explore the potential mechanisms underlying variation in leaf freezing tolerance. Electrolyte leakage began to increase for some of the treatments at −4 °C, and all treatments exhibited increased electrolyte leakage by −10 °C. There was a significant interaction between CO and N, whereby elevated CO alleviated the decrease in leaf freezing tolerance observed under high N. Treatment effects on freezing tolerance were not associated with changes in total sugar concentrations. Our results highlight that there are important interactions among global change factors that can alter plant freezing tolerance. [ABSTRACT FROM AUTHOR]

Biological soil crusts (BSCs) are the important components of alpine meadow ecosystems. The extent and morphology of BSCs vary greatly with alpine meadow retrogressive succession due to grazing pressure. There is significant interest in impacts of crust composition on plant seed germination, especially in (semi-) arid environments. However, little is known about the influences of BSCs, and their associations with alpine meadow succession, on germination of typical alpine meadow vascular plant species. In a full factorial common-garden experiment, we studied effects of: (1) crust type, (2) seed position, and (3) surface texture on seed germination. We chose three typical alpine meadow plant species (i.e. Poa pratensis, Tibetia himalaica and Potentillen nivea), which belonged to different functional groups (graminoids, legumes, and forbs) and play important roles in all alpine meadow succession stages. Crust type and seed position influenced seed germination, and the inhibitory effects of BSCs depended on the crust type and seed species tested. The major factors influencing seed germination were BSC type, seed position, soil texture, and the interactions between BSC type and seed position; species and seed position; species and surface texture; and species, crust type, and surface texture. Cyanobacteria crust significantly inhibited germination of all seeds. Seed position also had a significant effect on seed germination ( p < 0.001). Fewer seedlings germinated on the surface than below the surface, this was especially true for P. nivea. seeds within cyanobacteria and lichen crusts. Only germination rates of T. himalaica on the soil surface were significantly correlated with plant occurrence frequency within the alpine meadow community. The poor correlation for the other two species is possibly that they are perennials. Our results clearly demonstrated that BSCs can be biological filters during seed germination, depending on the BSC succession stage. Through their influences on seed germination, BSCs can strongly influence community assemblages throughout alpine meadow retrogressive succession. [ABSTRACT FROM AUTHOR]

To understand the mechanisms of heat stress responses in perennial grasses, differential proteins in leaves and roots of two genotypes of Kentucky bluegrass ( Poa pratensis), including heat-tolerant 'Midnight' and heat-sensitive 'Brilliant', were analyzed with two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS). Plants were exposed to heat stress for 28 days in growth chambers. Under 7-28 days of heat stress, leaf photochemical efficiency declined significantly while electrolyte leakage increased in leaves and roots, and to a lesser extent for heat-tolerant 'Midnight' than for heat-sensitive 'Brilliant'. Compared with leaves, cell membrane damage due to heat stress was more severe in roots. The 2-DE and MS analysis identified 37 heat-responsive proteins in leaves, 28 heat-responsive proteins in roots; 14 proteins in leaves and 9 proteins in roots exhibited differential expression between the two genotypes. The results indicate that proteins involved in metabolism and energy in leaves and those in antioxidant defense in roots are associated with heat tolerance in Kentucky bluegrass. The differential accumulation of these proteins might be the reason for different heat tolerance in two Kentucky bluegrass genotypes in aerial and underground parts. [ABSTRACT FROM AUTHOR]

A sustainable means of preventing polluted particulates carried in urban storm water entering rivers, groundwater and lakes is by employing vegetated sustainable drainage system (SUDS) devices, or best management practices to trap or biodegrade them. In the UK, a mixture of grass species is recommended for use in devices such as swales or filter strips. However, there is little evidence in support of the efficiency of the individual grasses or mixtures to deal with such contaminated material. A pot-based pollutant retention study was conducted using processed street dust from central Coventry, UK, as a simulated pollutant to be applied in different quantities to a variety of recommended grasses for vegetated SUDS devices. Analysis was conducted on compost cores, roots and shoots for heavy metals (Cd, Cu, Ni, Pb and Zn). Street dust mainly concentrated in the top compost layer for all grasses with only the finer material migrating down the profile. Analysis of roots indicated little accumulation, with ANOVA statistical tests indicating significant differences in heavy metal concentrations, with less in the compost and more in the shoots. Development of root systems on or near the surface possibly explains increased uptake of heavy metals by some species. Overall Agrostis canina and Poa pratensis showed the greatest accumulations compared to their controls although Agrostis capillaris syn.tenuis and Agrostis stolonifera also demonstrated accumulation potential. On ranking, Agrostis canina and Poa pratensis were highest overall. These rankings will assist in selecting the best grasses to address pollution of the urban environment by contaminated particulates. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Phleum alpinum L. and Poa pratensis L. are major forage species that often grow in various environments in Tierra del Fuego, Argentina. We performed a greenhouse experiment to investigate how these species acclimate to the different irradiance of the microenvironments where they grow. Both grass species were exposed to three levels of incident irradiance (I4: 4%; I26: 26%, or I64: 64% of ambient sunlight) and two levels of soil moisture content (M30: 30-50% or M60: 60-80% of field capacity) under greenhouse conditions. As irradiance levels increased, the contents of chlorophyll per unit surface area and fresh weight basis increased, and the chlorophyll a/ b and carotenoids/chlorophyll ratio also increased. Maximum photosynthetic rate and the light compensation point increased with increasing light availability. Values for these variables varied with time. However, the relationship of these values was not modified in P. alpinum between the irradiance treatments. Contrarily, temporal changes of those variables showed that the maximum photosynthetic rate was similar to that in March in all treatments in P. pratensis. Results indicated that P. alpinum and P. pratensis were able to acclimate to the various experimental environments. [ABSTRACT FROM AUTHOR]

Kentucky bluegrass ( Poa pratensis L.) is a very common grass species with a wide distribution, including in Mediterranean areas. The objective of this study was to investigate the effects of non-clavicipitaceous fungal endophytes on forage production by P. pratensis, and on the nutritive value and mineral status of its herbage. Plants were inoculated with each of eight endophytic species and grown under greenhouse conditions. After 3 months, the plants were harvested and dried before evaluating the following parameters: dry mass of herbage and roots, crude protein content, neutral detergent fibre content, and mineral contents in herbage. The results showed that endophytes affected the biomass yield (herbage and roots), fibre content, and mineral contents in the forage. Compared with controls, plants inoculated with Stemphylium globuliferum showed the highest herbage and root biomass values, whilst those inoculated with Embellisia leptinellae and S. globuliferum showed reduced fibre contents in herbage. Plants infected with Epicoccum nigrum and S. globuliferum showed increased herbage concentrations of calcium, magnesium, molybdenum, and titanium. These results demonstrate that inoculation of Poa pratensis with endophytes can increase its biomass yield and the nutritive value of its herbage. Therefore, endophyte inoculation may be a useful strategy to reduce nutrient deficiencies in P. pratensis forage. [ABSTRACT FROM AUTHOR]

Aims: We explored how climate warming and increased atmospheric nitrogen (N) deposition may influence grass litter decomposition over time, how litter quality versus environmental effects contribute to these responses, and the importance of these responses over winter. Methods: We used litter bags to examine decomposition over 2 years in a warming and N addition field experiment, and examined the contributions of litter quality and environment to these responses by transferring litter reciprocally between the treatment plots and a common garden. Results: Warming increased mass loss over the first year for Bromus inermis litter, which was consistent with the litter quality response, but by the second year there was no overall warming effect, and this change coincided with a negative environmental effect of warming. N addition increased mass loss and was more influential than warming in the early stages of Poa pratensis litter decomposition; the N effect appeared to be driven primarily by litter quality. Winter decomposition was not a substantial component of the treatment responses. Conclusions: Our results indicate that litter quality and environmental effects play different roles at different time scales in the decomposition responses of grass litter to warming and N addition, and these responses can be species specific. [ABSTRACT FROM AUTHOR]

PGR applications aimed to interfere with gibberellic acid (GA) biosynthesis or accumulation is a widespread practice in the production and maintenance of turfgrasses. If suppression of GA combined with drought stress modifies the content of other hormones in turfgrasses, PGR application could affect the susceptibility of grasses to various abiotic stresses and biotic pathogens. This growth chamber study aimed to investigate how drought stress and Primo (Syngenta Corp; Trinexapac-ethyl; TE) application affect the content of abscisic acid (ABA), auxin (in the form of indole acetic acid, IAA), jasmonic acid (JA), and salicylic acid (SA) in one commercially available cultivar 'Kenblue' and one experimental type, A06-46, of Kentucky bluegrass. Drought stress caused an accumulation of all four of these hormones that began around 8 day of drought stress or at a 20-40 % loss of water from leaves. TE application combined with drought stress caused an earlier increase in SA and IAA content and delayed the increase in JA and ABA content compared to drought-stressed plants not treated with PGR. An increase in SA, JA, and IAA was found at severe water deficit conditions (26 % RWC) in TE-treated plants compared to plants not treated with TE. The results indicate that both negative and positive consequences to plant defense strategies could result from the use of PGRs, which could potentially highly impact recommendations of how to best use PGR compounds in turfgrasses and other crop species. [ABSTRACT FROM AUTHOR]

Plants may survive salinity and alkalinity with differential metabolic responses. The aim of this study was to gain further insights into the differential response to salinity and alkalinity stress at the metabolic level. Two Kentucky bluegrass, 'Midnight' (tolerant) and 'Voyager II' (sensitive), were subjected to salinity (NaCl, 75 mM Na, pH 5.41) and alkalinity (NaCO and NaHCO, 75 mM Na, pH 9.5) in hydroponics. The leaf metabolite profile was determined using gas chromatography-mass spectrometry (GC-MS). Alkaline salts caused more severe damages than neutral salt as indicated by the vertical shoot growth rate (VSGR), turf quality, electrolyte leakage (EL) and lipid peroxidation (MDA content). Adaptation of plants to salinity was mainly associated with the accumulation of amino acids (proline, valine, glutamate, asparagine, glutamine, phenylalanine and lysine) and sugars (sucrose, trehalose). In contrast, the metabolic response to alkalinity stress was mostly associated with the accumulation of organic acids that are mainly sugar acids (gluconate, galactarate, glucarate) and those involved in the citric acid cycle (malate, citrate, isocitrate, succinate, maleiate, aconitate). The differential accumulation of the amino acids, organic acids, sugars and fatty acids may contribute to the differential adaptation strategies due to their roles in the stress response pathways such as osmotic adjustment, membrane stability, respiration for energy production, carbon/nitrogen assimilation, regulation of the intracellular pH and the pH outside roots. [ABSTRACT FROM AUTHOR]

In the Northern Great Plains, invasive grasses Bromus inermis (smooth brome) and Poa pratensis (Kentucky bluegrass) are substantial threats to remnant prairies because they form monotypic stands that decrease diversity and alter nutrient cycling. A greenhouse study was conducted to evaluate the competitive ability of these two invaders and how priority effects influence competition. We grew each invasive species alone, with a conspecific neighbor, and a native neighbor ( Elymus canadensis) to assess competitive ability. Priority treatments included planting both species concurrently, planting the invader prior to the native (by 21 days), and planting the native prior to the invader (by 21 days). Final aboveground biomass and a relative interaction index (RII) were used as response variables to determine the competitive ability of each species. Both competition and priority were found to have a significant effect on native and invasive species performance . Bromus inermis demonstrated a large competitive effect that increased with priority. Poa pratensis demonstrated smaller competitive effects but also benefited from priority. Unexpectedly, our native phytometer E. canadensis demonstrated a very strong competitive effect that, when coupled with priority, nearly excluded one of the invasive species. [ABSTRACT FROM AUTHOR]

A single colony of the non-native grass Poa pratensis L., which was introduced inadvertently to Cierva Point, Antarctic Peninsula, during the 1954-1955 season, was still present during a survey in February 2012, making it the longest surviving non-native vascular plant colony known in Antarctica. Since 1991, the grass cover has roughly tripled in size, with an annual increase in area of approximately 0.016 m, and an estimated maximum radial growth rate of 1.43 cm y. However, it remains restricted to the original site of introduction and its immediate surroundings (c. 1 m). Annual flowering of the plants occurred during the 2010/2011 and 2011/2012 seasons; however, there has been no seed production and only incomplete development of the sexual structures. Current environmental conditions, including low temperatures, may inhibit sexual reproduction. Lack of effective vegetative dispersal may be influenced by the low level of human activity at the site, which limits opportunities for human-mediated dispersal. Although P. pratensis has existed at Cierva Point for almost 60 years, it has not yet become invasive. Scenarios for the potential future development of the species in Antarctica and the associated negative impacts upon the native vegetation from competition are discussed in the context of regional climate change. Finally, we describe the environmental risk presented by P. pratensis and argue that this non-native species should be eradicated as soon as possible in accordance with the Protocol on Environmental Protection to the Antarctic Treaty. [ABSTRACT FROM AUTHOR]

Global climate change will likely result in the reduction of water levels in intermountain wetlands and ponds, and the vegetation communities associated with these wetlands are an important forage source for livestock. Lowered water levels will not only constrict wetland plant communities, it will potentially change aquatic and soil salt concentrations. Such an increase in salinity can reduce plant growth and potentially affect competitive interactions between plants. A greenhouse experiment examined the effects of salinity and competition on the growth of two wet meadow grass species, Poa pratensis (a glycophyte) and Puccinellia nuttalliana (a halophyte). The following hypotheses based on published data were tested: (1) Biomass of both species will decrease with increasing concentration of salt; (2) root:shoot (R:S) ratio of P. pratensis will decrease with increasing salt concentration while R:S ratio of P. pratensis and P. nuttalliana will increase with clipping; (3) competitive importance will decrease for P. pratensis and P. nuttalliana with increasing salt concentration because salt induces a stress response and competitive importance is reduced in stressed environments. A factorial design included 3 plant treatments ( P. nuttalliana alone, P. pratentsis alone, P. nuttalliana + P. pratensis) × 4 salinity rates (control; 5, 10, 15 g/L NaCl) × 2 clipping intensities (plants clipped or not clipped) for a total of 24 combinations replicated 6 times over a period of 90 days. We found a reduction in dry biomass as salinity increased, and this effect was greatest for P. pratensis. (1.94 g (SE 0.13) at 0 g/L NaCl to 0.22 g (SE 0.11) at 15 g/L NaCl). The R:S ratio of P. pratensis was reduced by salinity, but not for P. nuttalliana. Competitive importance of both species was reduced by clipping and by salinity, but the effect was greater and more consistent for P. pratensis. We conclude that salt concentration reduces plant growth and the effect of competition. [ABSTRACT FROM AUTHOR]

Frost damage can decrease nitrogen uptake by grasses over winter, and it can also decrease biomass production over the following growing season. However, it is not clear to what extent reduced nitrogen uptake over winter decreases grass production, or whether is it merely a symptom of root damage. We examined the growth response of the grass Poa pratensis L. (Kentucky bluegrass) to variation in the timing of freezing and nitrogen availability over winter in London, Ontario, Canada. All tillers were transplanted into untreated soil in early spring, and at peak seed maturation, root, shoot, and reproductive biomass were measured. There was an interaction between freezing and increased winter nitrogen availability, whereby nitrogen addition increased tiller biomass under ambient temperatures, but decreased tiller biomass in combination with a late winter freeze. The nitrogen response of ambient temperature tillers occurred primarily via increased seed production, whereas for frozen tillers seed production was generally absent. Our results support the hypothesis that nitrogen uptake over winter can increase growing season productivity in P. pratensis, but also demonstrate that increased nitrogen availability increases tiller vulnerability to frost. These results have important implications for grass responses to the alteration of soil freezing dynamics with climate change. [ABSTRACT FROM AUTHOR]

Soil alkalization is one of the most prominent adverse environmental factors limiting plant growth, while alkali stress affects amino acids and carbohydrates metabolism. The objective of this study was conducted to investigate the effects of alkali stress on growth, amino acids and carbohydrates metabolism in Kentucky bluegrass ( Poa pratensis). Seventy-day-old plants were subjected to four pH levels: 6.0 (control), 8.0 (low), 9.4 (moderate) and 10.3 (severe) for 7 days. Moderate to severe alkali stress (pH >9.4) caused a significant decline in turf quality and growth rate in Kentucky bluegrass. Soluble protein was unchanged in shoots, but decreased in roots as pH increased. The levels of amino acids was kept at the same level as control level at 4 days after treatment (DAT) in shoots, but greater at 7 DAT, when plants were subjected to severe (pH 10.3) alkali stress. The alkali stressed plants had a greater level of starch, water soluble carbohydrate and sucrose content, but lower level of fructose and glucose. Fructan and total non-structural carbohydrate (TNC) increased at 4 DAT and decreased at 7 DAT for alkali stressed plants. These results suggested that the decrease in fructose and glucose contributed to the growth reduction under alkali stress, while the increase in amino acids, sucrose and storage form of carbohydrate (fructan, starch) could be an adaptative mechanism in Kentucky bluegrass under alkali stress. [ABSTRACT FROM AUTHOR]

Plants have developed various mechanisms in adaptation to water deficit stress, including growth retardant to reduce water loss. Previous studies reported that plants treated with a growth inhibitor, trinexapac-ethyl (TE), had improved drought tolerance. The objective of this study was to determine alterations in proteins and metabolite accumulation associated with drought tolerance improvement in a perennial grass species, Kentucky bluegrass ( Poa pratensis), induced by TE application. Plants were treated with TE [1.95 ml l (v:v); a.i. TE = 0.113%] through foliar spray for 14 days, and then subjected to drought stress by withholding irrigation for 15 days in growth chambers. TE-treated plants exhibited significantly higher relative water content and photosynthetic capacity and lower membrane leakage than nontreated plants under drought stress, suggesting TE-enhanced drought tolerance in Kentucky bluegrass. Physiological improvement in drought tolerance through TE application was associated with the increased accumulation of various proteins and metabolites, including ferritin, catalase, glutathione-S-transferase, Rubisco, heat shock protein 70, and chaperonin 81, as well as fatty acids (palmitic acid, α-linolenic acid, linoleic acid, and octadecanoic acid). Our results suggest that TE may regulate metabolic processes for antioxidant defense, protective protein synthesis, photorespiration, and fatty acid synthesis, and thereby contribute to better drought tolerance in Kentucky bluegrass. [ABSTRACT FROM AUTHOR]

Field experiments were conducted to assess the influence of plant growth and amendment addition on phytostabilisation of copper (Cu), lead (Pb), manganese (Mn) and zinc (Zn) along highway soil in southwest British Columbia, Canada. The plant species tested were Lolium perenne L (perennial rye grass), Festuca rubra L. (creeping red fescue) and Poa pratensis L. (Kentucky blue grass) and the amendments, lime and phosphate. The treatment efficiencies were assessed during different seasons as a completely randomized factorial experiment in split plot design. The research tasks involved: (1) quantifying the seasonal extent of metal accumulation in soil and assessing the seasonal impact on metal speciation for different soil amendments and plant species; (2) determining seasonal accumulation differences between sampling periods in plant parts; and (3) assessing the influence of root-soil interactions on metal dynamics. The amendments decreased the exchangeable fraction and plant uptake of all four metals. The lowest mobile fractions (exchangeable and carbonate bound) were found in soils growing Festuca for Cu, Lolium for Mn and a Lolium/Poa/Festuca combination for Pb and Zn. Metal accumulation and metal dynamics in the rhizosphere soil are compared with those of the bulk soil. The final outcome was the development of a remediation strategy for all four metals involving suitable plants and amendments and incorporating seasonal and rhizosphere influences. [ABSTRACT FROM AUTHOR]

Despite increasing interest in the patterns of trace gas emissions in terrestrial ecosystems, little is known about the impacts of climate change on nitrous oxide (NO) fluxes. The aim of this study was to determine the importance of the three main drivers of climate change (warming, summer drought, and elevated CO concentrations) on NO fluxes from an extensively managed, upland grassland. Over a 2-year period, we monitored NO fluxes in an in situ ecosystem manipulation experiment simulating the climate predicted for the study area in 2080 (3.5°C temperature increase, 20% reduction in summer rainfall and atmospheric CO levels of 600 ppm). NO fluxes showed significant seasonal and interannual variation irrespective of climate treatment, and were higher in summer and autumn compared with winter and spring. Overall, NO emissions showed a positive correlation with soil temperature and rainfall. Elevated temperature had a positive impact on mean annual NO fluxes but effects were only significant in 2007. Contrary to expectations, neither combined summer drought and warming nor the simultaneous application of elevated atmospheric CO concentrations, summer drought and warming had any significant effect on annual NO fluxes. However, the maximum NO flux rates observed during the study occurred when elevated CO was combined with warming and drought, suggesting the potential for important, short-term NO-N losses in enriched CO environments. Taken together, our results suggest that the NO responses of temperate, extensively managed grasslands to future climate change scenarios may be primarily driven by temperature effects. [ABSTRACT FROM AUTHOR]

Apical meristems of multiple shoots produced from axenic seedlings of Kentucky bluegrass ( Poa pratensis L.) were used for Agrobacterium tumefaciens-mediated transformation. Transformation parameters were optimized for concentration of bacterial cells, duration of infection, and vacuum infiltration. The highest transformation frequency (1.42%) was obtained by infection with Agrobacterium suspension of OD600 = 0.6 for 5 min, under a negative pressure of 0.5 × 105 Pa. After co-cultivation, the herbicide-resistant plants were rooted and transplanted into flowerpots. Transgenic plants were confirmed by polymerase chain reaction (PCR) assay and Southern blot analysis. Using this transformation system, the betA gene encoding choline dehydrogenase and mutant als gene encoding the enzyme acetolactate synthase were introduced into three Kentucky bluegrass cultivars. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine the importance of protein synthesis during germination of white clover ( Trifolium repens) and Kentucky bluegrass ( Poa pratensis) and to assess the impact of osmopriming on seed germination in the presence of cadmium. Cycloheximide (Cx, 20 and 100 μM), a translation inhibitor, delayed germination and reduced final germination percentage in both species, although to a higher extent in P. pratensis than in T. repens. This suggests that in white clover, some proteins involved in reserve mobilisation and metabolic activation were already present in mature seeds. Actinomycin-D (Act-D; 20 and 100 μM) and α-amanitin (α-Am 20 μM), both inhibitors of transcription, did not reduce P. pratensis germination, demonstrating that for this species, transcription is not essential for radicle protrusion and that long-lived mRNA are used for initial protein synthesis. In contrast, incised white clover seeds showed delayed germination in presence of α-Am, suggesting that expression of some specific genes may help in the first germination steps. Osmopriming (PEG 8,000 60%) improved germination of seeds exposed to 100 μM Cd but the positive effect of this pretreatment was suppressed ( T. repens) or drastically mitigated ( P. pratensis) when Act-D or Cx were added to the priming medium. Cadmium reduced α- and β-amylase activities in germinating seeds but osmoprimed seeds exhibited higher activities than unprimed seeds. The presence of inhibitors in the priming medium reduced α- and β-amylase activities. These results suggest that the two studied species differed significantly in the mechanisms occurring during early seed germination and that the beneficial effect of priming requires gene expression and protein synthesis. [ABSTRACT FROM AUTHOR]

We tested the efficacy of matrix-based fertilizers (MBFs) to improve Kentucky bluegrass ( Poa pratensis L.) growth while reducing NH, NO3, dissolved reactive phosphorus (DRP), and total phosphorus (TP) compared to commercial slow-release fertilizer (SRF) Polyon®, ESN®, and Avail® in greenhouse column studies. The MBFs covered a range of inorganic N and P in compounds that are relatively loosely bound (MBF6) and more tightly bound compounds (MBF7) with Al(SO4)318H2O and/or Fe2(SO4)33H2O and with high ionic exchange compounds starch, cellulose, and lignin. The total amount of NO3 and NH4 leached was greater from columns receiving Polyon® and ESN® fertilizers than all other treatments. The MBF6+Avail® or MBF7+Avail® fertilizers leached 64–68% less NO3 than Polyon® (43-0-0) and ESN® (46-0-0), and 73–76% less TDP and TP than Avail® (10-34-0). A greater amount of NO3 was leached from the MBF6+Avail® and the MBF7+Avail® treatments than the other MBF fertilizer treatments. Shoot and root biomass were greater when plants received the Avail ®, MBF6+Avail®, and MBF7+Avail® fertilizer treatments than the other fertilizer treatments. When combined with small quantities of commercial SRFs, these new MBFs were able to maintain plant growth while reducing N and P leaching. These new MBF formulations do not depend on organic or inorganic coatings to reduce N and P leaching and with further testing and development could be effective commercial fertilizers. [ABSTRACT FROM AUTHOR]

Genetic diversity within species is a potentially important, but poorly studied, determinant of plant community dynamics. Here we report experiments testing the influence of genotype identity and genotypic diversity both on the invasibility of a foundation, matrix-forming species (Kentucky bluegrass, Poa pratensis), and on the invasiveness of a colonizing species (dandelion, Taraxacum officinale). Genotypes of Kentucky bluegrass in monoculture showed significant variation in productivity and resistance to dandelion invasion, but the productivity and invasion resistance of genotypic mixtures were not significantly different from those of genotypic monocultures. Indirect evidence suggested temporal shifts in the genotypic composition of mixtures. Dandelion genotypes in monoculture showed striking and significant variation in productivity and seed production, but there was no significant tendency for these variables in mixtures to deviate from null expectations based on monocultures. However, productivity and seed production of dandelion mixtures were consistently greater than those of the two least productive genotypes, and statistically indistinguishable from those of the three most productive genotypes, suggesting the possibility of greater invasiveness of genotypically diverse populations in the long run due to dominance by highly productive genotypes. In both experiments, the identity of genotypes was far more important than genetic diversity per se. [ABSTRACT FROM AUTHOR]

Some perennial grasses secrete phytosiderophores from the roots in response to Fe-deficiency. Here, we characterized the pattern of phytosiderophore secretion by Lolium perenne (cv. ‘Tove’) and Poa pratensis (cv. ‘Baron’), which are used to correct iron-deficiency induced chlorosis in fruit trees grown on calcareous soils. Both species showed a distinct diurnal rhythm in phytosiderophore secretion, but the secretion time differed between species; the secretion peak time was about 2 h earlier in L. perenne than in P. pratensis under the same growth conditions. The secretion time was shifted by changing temperature during the collection of phytosiderophores in both L. perenne and P. pratensis. Increasing root-zone temperature resulted in earlier secretion, while lowering the temperature resulted in delayed secretion. Furthermore, this shift of secretion time was achieved by changing the temperature around the root-zone. Shading treatment during the secretion period did not affect the secretion time in either species. These results indicate that the secretion of phytosiderophore is triggered by the temperature around the roots, but not light, in these two perennial grasses. [ABSTRACT FROM AUTHOR]

Abstract  An endophytic bacterium, wild poplar strain B (WPB), isolated from stems of wild cottonwood (Populus trichocarpa) was identified to Burkholderia vietnamiensis by analyzing the recA and rDNA genes. Phylogenetic analysis of the nifHDK cluster indicates that the WPB isolate shares high sequence similarity with known B. vietnamiensis strains. The nitrogenase activity of WPB was determined by a 15N2 incorporation assay and an acetylene reduction assay. WPB was also monitored for production of indole-3-acetic acid (IAA), a phytohormone which can promote plant growth, when incubated with l-tryptophan. In addition, its plant growth promotion capacity was assessed by inoculating the WPB strain onto Kentucky bluegrass in nitrogen-free medium. Compared to uninoculated control plants, the plants inoculated with WPB gained more dry weight (42%, p = 0.01) and more nitrogen content (37%, p = 0.04) in 50 days. [ABSTRACT FROM AUTHOR]

Waterlogging often occurs simultaneously with high temperatures during summer. The objective of this study was to characterize anaerobic metabolism and transcript abundance of fermentative enzymes in roots of Kentucky bluegrass ( Poa pratensis L.) in response to short-term waterlogging and high temperature stresses. Grasses were subjected to four treatments: (1) well-drained under normal temperature (20/15°C, day/night; control); (2) waterlogging under normal temperature (WL); (3) well-drained under high temperature (35/30°C, day/night; HT); and (4) waterlogging under high temperature (WL + HT). Greater reductions in leaf elongation rate and shoot dry mass were observed under WL + HT than either stress alone. Root water-soluble carbohydrate concentration decreased 45% and 46% at 3 and 5 days of WL + HT, respectively, compared to the control. At 5 days, activities of root alcohol dehydrogenase increased 93% and 90% and lactate dehydrogenase increased 95% and 98% under WL and WL + HT, respectively, compared to the control. Transcript abundance of ADH and PDC genes in the roots were not or only slightly shown under the control or HT conditions but were induced by WL or WL + HT, particularly under WL. The results indicated that short-term WL + HT induced root anaerobic metabolism in a similar way to WL alone but had more severe effects on leaf growth and root WSC than did WL in Kentucky bluegrass. [ABSTRACT FROM AUTHOR]

We studied the early stages of embryo formation in apomictic Poa pratensis L. It was shown that during transition to parthenogenesis, at least at the initial stages of embryogenesis, the algorithm of development of the sexual embryo is preserved. This could be due to the system of genetic control of embryogenesis, common for amphimixis and apomixis. We described asynchrony of developmental processes both within the efflorescence (asynchronous maturation of seed-buds) and within the seed-bud and even gametophyte (different timing of induction of apoarchesporic initials and oospores). This feature of pseudogamous apomicts allows them to produce simultaneously both sexual and apomictic progenies. [ABSTRACT FROM AUTHOR]

Plants were regenerated from tissue cultures of embryos dissected from seeds that were harvested from a self-pollinated clonal selection of Kentucky bluegrass ( Poa pratensis L.) ‘Baron’, an apomictic cultivar. Plants were regenerated from 35 embryo-derived callus cultures of the 3280 embryos that were plated. Flow-cytometric (FCM) and RAPD-marker analyses were performed to determine if regenerants were or were not apomictic in origin. Fifteen regenerants with a 3c DNA content were classified as arising from 2 n + n aberrant embryos, which was a higher frequency than expected, based on a chi-square analysis. Of the remaining 20 regenerants with a 2c DNA content, a chi-square test showed that all could have arisen from n + n sexually-derived embryos, based on the observed segregation of n + n regenerants, which fit the expected 3:1 ratio of dominant:recessive RAPD-marker phenotypes. The apparent lack of regenerants of apomictic origin, and implications for genetic transformation and breeding of Kentucky bluegrass are discussed. [ABSTRACT FROM AUTHOR]

To determine the characteristics of seed reproduction in the Kentucky bluegrass (Poa pratensis L.), individual seed variability with respect to the composition of endosperm storage proteins was studied. Comparative analysis of caryopses obtained by self-fertilization and free fertilization of plants I1 (no. 2-4) and I2 (no. 2-4-7) of the wild-type specimen Murmanskii 95 was performed by means of SDS-PAGE. Using a cytoembryological express method, we demonstrated that facultative stimulation-autonomous apomeiotic apomixis, along with the formation of meiotic megasporocytes, is characteristic of the Kentucky bluegrass. This method made it possible to determine the consequences of meiotic processes in the maternal plant and to reveal the hybrid nature of seed endosperm. [ABSTRACT FROM AUTHOR]

The effect of the community composition of soil microbes on ecosystem processes has received relatively little attention. Here we examined the variation in soil microbial composition in a Yellowstone National Park grassland and the effect of that variation on the growth, in a greenhouse, of the dominant grass in the community. Plants and their rhizospheric soil were collected from paired, Poa pratensis-dominated grassland plots located inside and outside a 40-year-old exclosure. P. pratensis aboveground, belowground, and whole plant growth were greater in pots with soil communities from grazed grassland compared to fenced grassland, indicating (1) soil microbial communities differed, and (2) this difference influenced the growth of the plant that dominated both grasslands. Treating pots with fungicide (benomyl) suppressed the soil community influence, indicating that different fungal communities caused the soil microbe effect. In addition, two lines of evidence are consistent with the hypothesis that arbuscular mycorrhizal fungal (AMF) species composition affected P. pratensis: (1) a divergence in AMF spore communities in the two field soils, and (2) little evidence of pathogenic fungi. These findings emphasize the need to examine the role that the composition of the soil microbial community plays in controlling terrestrial ecosystems. [ABSTRACT FROM AUTHOR]

Characterization of germplasm collections is critical to assesscollection diversity and enhance utilization. A Poapratensis L. germplasm collection of 228 accessionsrepresenting 26 countries, along with 17 commercial check cultivars,was characterized using 86 random amplified polymorphic DNA(RAPD) markers and 17 agronomic descriptors. The Dicesimilarity coefficient used for RAPD data ranged from 0.56 to 0.95and average Euclidean distance used for agronomic data ranged from0.28 to 2.52. No two accessions had a similarity of one or a distanceof zero, showing there were no duplicate entries. Cluster analysis ofRAPD data using the unweighted pair-group method usingarithmetic averages (UPGMA) revealed 11 accessions withparticularly low similarity values. These were subsequently found tobe misidentified Poa species (one each of P. alpina, P. compressa, P. glauca, P. urssulensis and seven P. trivialis). ForRAPD data, 62% of the entries were in one large cluster with46 additional clusters containing one to 13 accessions. For agronomicdata, 89% of the entries were in four main clusters. Thisclustering pattern for RAPD and agronomic data suggested uniquegenotypes were generally under represented in the collection. Theagronomic-based clusters showed some broad separation byaccession origin, but in general, origin did not correspond closelywith the clustering pattern. The correlation between the RAPD andagronomic-based distance matrices, excluding misidentifiedaccessions, was highly significant (P<0.01) (n= 234, r = − 0.14). However, the correlationrepresented a relatively small fraction of the total variation,indicating that both molecular and agronomic characterizations wereneeded to assess overall diversity. [ABSTRACT FROM AUTHOR]

The high versatility of the mode of reproduction and the retention of a pollen recognition system are the factors responsible for the extreme complexity of the genome in Poa pratensis L. Two genetic maps, one of an apomictic and one of a sexual genotype, were constructed using a two-way pseudo-testcross strategy and multiplex PCR-based molecular markers (AFLP and SAMPL). Due to the high ploidy level and the uncertainty of chromosome pairing-behavior at meiosis, only parent-specific single-dose markers (SDMs) that segregated 1:1 in an F1 mapping population (161 out of 299 SAMPLs, and 70 out of 275 AFLPs) were used for linkage analysis. A total of 41 paternal (33 SAMPLs and 8 AFLPs) and 47 maternal (33 SAMPLs and 14 AFLPs) SDMs, tested to be linked in coupling phase, were mapped to 7+7 linkage groups covering 367 and 338.4 cM, respectively. The comparison between the two marker systems revealed that SAMPL markers were statistically more efficient than AFLP ones in detecting parent-specific SDMs (75% vs 32.4%). There were no significant differences in the percentages of distorted marker alleles detected by the two marker systems (27.8% of SAMPLs vs 21.3% of AFLPs). The pairwise comparison of co-segregational groups for linkage detection between marker loci suggested that at least some of the P. pratensis chromosomes pair preferentially at meiosis-I. [ABSTRACT FROM AUTHOR]

Investigates the photosynthesis, respiration and carbon allocation of cool-season perennial grasses, Kentucky bluegrass or Poa pratensis and tall fescue of Festuca arundinaceae, in response to surface soil drying. Plant materials and growth conditions; Leaf water status; Canopy net photosynthetic and respiration rates; Root respiration rate.

Infection of Poa pratensis leaf blades and callus tissue by Bipolaris sorokiniana increases the production of ethylene and ethane. The ethylene is responsible for most of the chlorosis that occurs during pathogenesis. The nonselective toxin(s) produced by B. sorokiniana is known to disrupt membranes and to damage chlorophyll, but it is not known whether it can induce an increase in ethylene or ethane. Research was initiated to determine the effect of a biologically-active extract of B. sorokiniana on the endogenous ethylene and ethane of intact P. pratensis leaf blades and on subsequent development of chlorosis. The extract did not increase endogenous ethylene of treated leaves, but it was associated with an increase in endogenous ethane between 24 and 96 h after treatment. Chlorophyll loss occurred 96 h after treatment and persisted for the duration of the study (168 h). The chlorophyll content of treated leaf blades ranged from 72% to 80% of control leaf blades. The observations suggest that the extract of B. sorokiniana can induce chlorophyll loss from treated leaf blades independent of an increase in endogenous ethylene by directly damaging chloroplasts with a concurrent release of ethane. The ethane is believed to be a by-product of pathogenesis. [ABSTRACT FROM AUTHOR]

The article presents a study that aims to assess the persistence of several pesticides applied to turfgrass foliage that was subsequently used for compost. Five pesticide products including chlorpyrifos, triclopyr plus 2,4-D, triclopyr plus clopyralid, isoxaben, and flurprimidol were applied to 0.07-hectare plot of a mixed stand of Kentucky bluegrass (Poa pratensis), perennial ryegrass (Lolium perenne), and fine fescue (Festuca sp). Results of the study confirm the long half-life in that at 56 days chlorpyrifos was still detectable at 0.7 ppm and 0.1 ppm at 128 days. Some of the persistence can be related to its strong sorption to soil particles and grass.

Plant regeneration in Kentucky bluegrass ( Poa pratensis L. cv. Touchdown) via culture of seedling tissues was investigated. When coleoptile, leaf, and stem sections of dark-germinated seedlings were cultured on Murashige and Skoog (MS) medium, different types of callus were produced, depending on the expiant source and growth regulator combinations. Only compact-friable callus (type 3) and moderately compact, friable callus (type 2) produced shoots upon subculture. The nonstructured watery callus (type 4) produced roots without shoots. Shoot differentiation from callus tissues was highest when the culture medium contained 0.2 mgL picloram + 0.01 mgL α-naphthaleneacetic acid (NAA). Calli grown from coleoptiles had higher shoot regeneration frequency (32%) than that obtained from either stem sections (12%) or young leaf tissues (2%) of the same seedlings. Some organogenic callus lines produced exclusively green plants, while others produced albino shoots or a mixture of green and albino shoots. The green plants were multiplied in a medium containing 0.1 mgL BAP plus either 0.2 mgL picloram or 0.1 mgL indole-3-acetic acid (IAA). Over 90% of the cultures in the shoot proliferation medium produced roots in 4 weeks. The rooted plants were successfully established in soil medium and grown in the greenhouse. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated the dissipation of dichlorvos' and chlorpyrifos' dislodgeable foliar residue on turf. The study applied dichlorvos/dichlorovinyl dimethyl phosphate (DDVP) and chlorpyrifos pesticides on turf plots found in Folsom, Sacramento County, California. It says that under breezy, moist, and cool autumnal conditions in California, dichlorvos and chlorpyrifos dissipated to lower than estimated safe degrees after two hours in Kentucky bluegrass lawn.

Gametophytic apomixis in Kentucky bluegrass ( Poa pratensis L.) involves the parthenogenetic development of unreduced eggs from aposporic embryo sacs. Attempts to transfer the apomictic trait beyond natural sexual barriers require further elucidation of its inheritance. Controlled crosses were made between sexual clones and apomictic genotypes, and the parthenogenetic capacity of (poly)diploid hybrids was ascertained by the auxin test. A bulked segregant analysis with RAPD and AFLP markers was then used to identify a genetic linkage group related to the apomictic mode of reproduction. This approach enabled us to detect both an AFLP marker located 6.6 cM from the gene that putatively controls parthenogenesis and a 15.4-cM genomic window surrounding the target locus. A map of the P. pratensis chromosome region carrying the gene of interest was constructed using additional RAPD and AFLP markers that co-segregated with the parthenogenesis locus. Highly significant linkage between parthenogenesis and a number of AFLP markers that also appeared to belong to a tight linkage block strengthens the hypothesis of monogenic inheritance of this trait. If a single gene is assumed, apomictic polyploid types of P. pratensis would be simplex for a dominant allele that confers parthenogenesis, and this genetic model would be further supported by the bimodal distribution of the degree of parthenogenesis exhibited in the (poly)diploid progenies from sexual x apomictic matings. The molecular tagging of apomixis in P. pratensis is an essential step towards marker-assisted breeding and map-based cloning strategies aimed at investigating and manipulating its mode of reproduction. [ABSTRACT FROM AUTHOR]

Background: Transgenic herbicide-resistant (HR) turfgrass together with its associated, broad spectrum herbicides promise cheap, selective and efficient weed control by excluding infested weeds resulting in turf lawn with high uniformity and aesthetic value. The concept of this "weeding program" initiated from modern biotechnology has been widely implemented in several principal crops including maize, soybean, canola and cotton as early as the 1990s. Transgenic HR turfgrass classified as a genetically modified organism (GMO) has undoubtedly caused public concern with respect to its biosafety and legalities similar to well-established HR crops. Nevertheless, applying metabolomics-based approaches which focuses on the identification of the global metabolic state of a biological system in response to either internal or external stimuli can also provide a comprehensive characterization of transgenic grass metabolism and its involvement in biosecurity and public perception. Aim of review: This review summaries the recent applications of metabolomics applied to HR crops to predict the molecular and physiological phenotypes of HR turfgrass species, glyphosate-resistant Kentucky bluegrass (Poa pratensis L.) and glufosinate-resistant creeping bentgrass (Agrotis stonifera L.). Additionally, this review also presents background knowledge with respect to the application of metabolomics, transformation of HR crops and its biosafety concerns, turfgrass botanical knowledge and its economic and aesthetic value. Key scientific concepts of review: The purpose of this review is to demonstrate the molecular and physiological phenotypes of HR turfgrass based on several lines of evidence primarily derived from metabolomics data applied to HR crops to identify alterations on HR turfgrass metabolism as a result of genetic modification that confers resistant traits. [ABSTRACT FROM AUTHOR]

The article discusses the case of the genetically modified (GM) Kentucky bluegrass that fell outside the regulatory authority of the U.S. Department of Agriculture. The case is noted to be the first time that a large company has taken advantage of the critical weakness in the regulation of GM plants. The grass maker Scotts Miracle-Gro is reported to have chosen the Kentucky bluegrass for the simplicity of both the genetic materials used to create it and the patent associated with it.

The article focuses on the announcement made by the U.S. Department of Agriculture (USDA) regarding their authority to regulate genetically modified (GM) crops. It states that Scotts Miracle-Gro Co. is in the stage of developing Kentucky bluegrass, a variety of Poa pratensis which is resistant to glyphosate herbicide. It says that USDA Secretary Tom Vilsack wrote to the lawn-care company to inform that the said grass variety is not covered with the regulations governing other GM crops.

This article reports that a U.S. court blocked open-air field trials for genetically modified creeping bentgrass and Kentucky bluegrass. The experimental grasses spread beyond the test field because the plans for the trial were approved without assessing their environmental impact on the area. The company Scotts Grass appealed the court's decision.