expression of a higher plant psba gene in synechocystis 6803 yields a functional hybrid photosystem ii reaction center complex.the psba gene codes for the d1 polypeptide of the photosystem ii reaction center complex and is found in all photosynthetic organisms that carry out oxygenic photosynthesis. here we describe the construction and characterization of a strain of the cyanobacterium synechocystis sp pcc 6803 in which the three endogenous psba genes are replaced by a single psba gene from the chloroplast genome of the higher plant poa annua. the resulting chimeric strain, kwpas, grows photoautotrophically with a doub ...19911840918
[annual meadowgrass (poa annua l.) pollinosis. early spring pollinosis caused by grass pollens]. 19873592992
a diploid population of poa annua l. from australia. 19705483779
leifsonia poae gen. nov., sp. nov., isolated from nematode galls on poa annua, and reclassification of 'corynebacterium aquaticum' leifson 1962 as leifsonia aquatica (ex leifson 1962) gen. nov., nom. rev., comb. nov. and clavibacter xyli davis et al. 1984 with two subspecies as leifsonia xyli (davis et al. 1984) gen. nov., comb. nov.the new genus leifsonia gen. nov. with two new species, leifsonia poae sp. nov. (type strain vkm ac-1401t) and leifsonia aquatica (ex leifson 1962) nom. rev., comb. nov. (the type species, with vkm ac-1400t = dsm 20146t = jcm 1368t as type strain), is proposed to accommodate bacteria found in poa annua root gall, induced by the nematode subanguina radicicola, and 'corynebacterium aquaticum' leifson 1962. further, it is proposed to reclassify clavibacter xyli davis et al. 1984 with two subspecies ...200010826825
no difference in activity of sod-1 genotypes of poa annua to short-term treatment of ambient gaseous organic pollution.our previous studies indicated that genotypes at locus sod-1 of poa annua changed clinally along a gradient of gaseous organic pollution. in the present study, we aimed to know whether there were differential responses of activities of different superoxide dismutase (sod) genotypes to short-term treatment of ambient gaseous organic pollution. significant bias from hardy-weinberg equibrium was observed on locus sod-1, and no genotype sod-1-bb was found. significantly increased activities were obs ...200516313021
spatial patterns and species performances in experimental plant communities.amongst the various hypotheses that challenged to explain the coexistence of species with similar life histories, theoretical, and empirical studies suggest that spatial processes may slow down competitive exclusion and hence promote coexistence even in the absence of evident trade-offs and frequent disturbances. we investigated the effects of spatial pattern and density on the relative importance of intra- and interspecific competition in a field experiment. we hypothesized that weak competitor ...200516001215
vegetation pattern and heavy metal accumulation at a mine tailing at gyöngyösoroszi, hungary.vegetation at an abandoned heavy metal bearing mine tailing may have multifunctional roles such as modification of water balance, erosion control and landscape rehabilitation. research on the vegetation of mine tailings can provide useful information on tolerance, accumulation and translocation properties of species potentially applicable at moderately contaminated sites. analyses of the relationship between heavy metal content (pb, zn and cu) and vegetation in a mine tailing were carried out. t ...200515948607
vegetation pattern related tc grazing pressure in alpine meadows of nanda devi biosphere reserve.the present study aims to analyze the interaction of prevailing biotic pressure on plant species diversity in nanda devi biosphere reserve (ndbr) which lies in northern part of uttaranchal hills between 79 degrees 40'e to 80 degrees 05'e longitude and 30 degrees 17' n to 30 degrees 41'n latitude and covers an area of 2236.7 km2. a total of 75 species has been found which included the herbaceous plants viz., grasses, sedges and forbs. generally, the plants have a short life span of 3-4 months. ho ...200415847338
the standardization of poa annua as an indicator of smog concentrations. i. effects of temperature, photoperiod, and light intensity during growth of the test-plants. 195716655051
the infection process of colletotrichum graminicola and relative aggressiveness on four turfgrass species.detached 3-week-old leaves of agrostis palustris, lolium perenne, poa annua, and poa pratensis were inoculated with conidial suspensions of two isolates of colletotrichum graminicola obtained from a. palustris. inoculated leaves were incubated at 23 degrees c under high relative humidity (>95%). the infection process was investigated by light microscopy from 2 to 168 h after inoculation (ai). spore germination was observed within 2 h ai, appressoria within 6 h ai, and penetration pores within 8 ...200314569284
[effects of land utilization of sewage sludge on grass and soils].effects of land disposal of sewage sludge on grass and soil environment were studied. the sewage sludge used was from northern shenyang wastewater treatment plant. the results showed that contents of nutrient in the soil were increased after sewage sludge application, especially for organic matter. grass biomass were increased and the green period were extended with a better growth of the lawn. the heavy metal contents in the soil were increased with cd contents beyond 2nd grade national environ ...200312800658
genetic structure along a gaseous organic pollution gradient: a case study with poa annua l.the population genetic composition of poa annua l. was studied by starch electrophoresis along a transect running ne from an organic reagents factory at shanghai, china. five enzyme systems were stained. we have reached the following preliminary conclusions: (1). organic pollution has dramatically changed genotypic frequencies at some loci of poa annua populations. at polluted sites, significant deviations from hardy-weinberg equilibrium were observed on loci sod-1 and me due to the excess of he ...200312758025
effects of elevated soil copper on phenology, growth and reproduction of five ruderal plant species.the repeated use of copper (cu) fungicides to control vine downy mildew, caused by plasmopara viticola, has been responsible for the heavy increase of cu concentration in the upper layers of vineyard soils. to determine the effects of elevated soil cu on plant development, we created an artificial soil gradient with cu enrichments ranging from 0 to 400 mg kg-1. on this gradient, and for five ruderal plant species commonly found in vineyards in southern france (poa annua l., dactylis glomerata l. ...200312547525
stranded arrangement of sporopollenin in the exine of microspores of poa the early microspore wall of the grass poa annua l., sporopollenin is arranged in bundles of anastomosing strands. each bundle contains at least two strands, each about 50 a in diameter, which anastomose or intertwine and look like a meshwork with pores of the mesh up to 50 a in diameter. after the early microspore stage the exine becomes homogeneous; it is similar in this respect to the exines or ornamented parts of the exines of pollen of other angiosperms examined by electron microscopy.196217749629
leaf respiration in light and darkness (a comparison of slow- and fast-growing poa species).we investigated whether leaf dark respiration (nonphotorespiratory mitochondrial co2 release) is inhibited by light in several poa species, and whether differences in light inhibition between the species are related to differences in the rate of leaf net photosynthesis. four lowland (poa annua l., poa compressa l., poa pratensis l., and poa trivialis l.), one subalpine (poa alpina l.), and two alpine (poa costiniana vick. and poa fawcettiae vick.) poa species differing in whole plant relative gr ...199712223656
ethylene emission and responsiveness to applied ethylene vary among poa species that inherently differ in leaf elongation rates.a plant's ability to produce and respond to ethylene is essential for its vegetative growth. we studied whole-shoot ethylene emission and leaf growth responses to applied ethylene in four poa spp. that differ inherently in leaf elongation rate and whole-plant relative growth rate. compared with the fast-growing poa annua and poa trivialis, the shoots of the slow-growing species poa alpina and poa compressa emitted daily 30% to 50% less ethylene, and their leaf elongation rate was more strongly i ...200212114591
role of sugars and organic acids in regulating the concentration and activity of the alternative oxidase in poa annua roots.detached roots of poa annua were used to study alternative oxidase protein expression upon the addition of sucrose, glucose, fructose, inositol, mannitol, citrate or malate, at a concentration of 1 or 10 mm for 24 h. after 24 h the capacity of cytochrome c oxidase was decreased equally in all treatments. only citrate induced the expression of the alternative oxidase, especially at a concentration of 1 mm (15-fold). the activity of the alternative pathway (measured with the (18)o-fractionation te ...200211971919
can meristematic activity determine variation in leaf size and elongation rate among four poa species? a kinematic study.we studied inherent variation in final leaf size among four poa spp. that live at different elevations. the average final length of leaf 7 of the main stem of the smallest species (poa alpina) was only one-half that of the largest species (poa trivialis); it was correlated with leaf elongation rate, but not with the duration of leaf elongation. a faster rate of leaf elongation rate was associated with (a) larger size of the zone of cell expansion, and (b) faster rates of cell production (per cel ...200011027732
the alternative oxidase in roots of poa annua after transfer from high-light to low-light conditions.the activity of the alternative pathway can be affected by a number of factors, including the amount and reduction state of the alternative oxidase protein, and the reduction state of the ubiquinone pool. to investigate the importance of these factors in vivo, we manipulated the rate of root respiration by transferring the annual grass poa annua l. from high-light to low-light conditions, and at the same time from long-day to short-day conditions for four days. as a result of the low-light treat ...200010972888
effects of carbon dioxide and nitrogen fertilization on phenolic content in poa annua l.different but partially overlapping hypotheses have been developed to predict the allocation of phenolics in elevated atmospheric co(2). the carbon-nutrient balance hypothesis predicts increased allocation to phenolics due to reduced relative availability of nitrogen. the growth-differentiation balance hypothesis states that allocation will depend on source and sink strength, while the protein competition model predicts that allocation will remain unchanged. we grew poa annua at two co(2) concen ...200010913845
capsella bursa-pastoris (l.) medic. as a biomonitor of heavy metals.capsella bursa-pastoris (l.) medic. (shepherd's purse) has been tested as a possible biomonitor of heavy metals in the city of bradford, uk and compared with poa annua l. (annual meadow-grass), a species with a similar ecology that had previously been studied for biomonitoring potential. forty-two sites (urban roadside, urban, urban park, suburban and rural) in and around bradford were investigated. concentrations of pb, cd, zn and cu have been determined in soils and in washed and unwashed plan ...199910085567
the role of the alternative oxidase in stabilizing the in vivo reduction state of the ubiquinone pool and the activation state of the alternative oxidasea possible function for the alternative (nonphosphorylating) pathway is to stabilize the reduction state of the ubiquinone pool (qr/qt), thereby avoiding an increase in free radical production. if the qr/qt were stabilized by the alternative pathway, then qr/qt should be less stable when the alternative pathway is blocked. qr/qt increased when we exposed roots of poa annua (l.) to increasing concentrations of kcn (an inhibitor of the cytochrome pathway). however, when salicylhydroxamic acid, an ...19989765546
susceptibilities of different test systems from maize (zea mays), poa annua, and festuca rubra to herbicides that inhibit the enzyme acetyl-coenzyme a carboxylasethe susceptibilities of maize (zea mays cv. champ) and two graminicide-resistant grass species, poa annua (annual meadow grass) and festuca rubra (red fescue), to two aryloxyphenoxypropionates (quizalofop and fluazifop) and a cyclohexanedione (sethoxydim) graminicide were evaluated in leaf blades and isolated chloroplasts, and by assaying acetyl-coenzyme a carboxylase (accase) in desalted leaf homogenates. the graminicide resistance of p. annua and f. rubra appeared to be at the level of accase. ...19968980037
transmission of a leafhopper-borne virus from naturally infected poa annua in czechoslovakia. 19685654128
a new gall-forming species of anguina scopoli, 1777 (nemata: anguinidae) on bluegrass, poa annua l., from the coast of california.anguina pacificae n. sp. is described and illustrated from stem galls on bluegrass, poa annua l., from golf courses along coastal california. the females are characterized by constrictions in the anterior and posterior connections of the isthmus with the respective parts of the esophagus, the long multicellular columella, and the sharply pointed tail tip. males are dorsally curved after death; body width is increased markedly after 13 annuli in both sexes, and the tail is conical and with an acu ...198419294043
insecticides and arable weeds: effects on germination and seedling growth.the decline of many arable weed species in northern europe has been attributed to the intensification of modern agriculture and in particular, increasing pesticide use. in this study, we examined the effect of two insecticides, dimethoate and deltamethrin, on the germination and seedling growth of six arable weed species. although germination was unaffected by insecticide application, seedling growth of four species was decreased by exposure to deltamethrin (capsella bursa-pastoris and poa annua ...200516385742
[effects of simulated nitrogen deposition on weeds growth and nitrogen uptake].in this paper, a greenhouse experiment was conducted to study the responses of different functional groups weeds to simulated nitrogen deposition (4.0 g n.m(-2).yr(-1)). native weed species poa annua, lolium perenne, avena fatua, medicago lupulina, trifolium repens, plantago virginica, veronica didyma, echinochloa crusgalli var. mitis, eleusine indica and amaranthus spinosus in orchard ecosystem were used test materials, and their above-and underground biomass and nitrogen uptake were measured. ...200516110678
[allelopathy and chemical constituents of ligularia virgaurea volatile].ligularia virgaurea is a noxious weed widely distributed on the psychro-grasslands of east qinghai-tibet plateau of china, but the allelopathic effects of its volatile is less known. in this study, the allelopathy of l. virgaurea volatile to 5 kinds of grasses was examined, and its chemical constituents were analyzed by gc-ms. the results demonstrated that the volatile of growing l. virgaurea could inhibit the seed germination speed and germination rate of all tested grasses. the inhibitory effe ...200516422498
a psba mutation in kochia scoparia (l) schrad from railroad rights-of-way with resistance to diuron, tebuthiuron and metribuzin.kochia [kochia scoparia (l) schrad] has become resistant to many herbicides used in cropland and railroad rights-of-way in north dakota and minnesota. kochia scoparia plants that had survived annual treatments with diuron and tebuthiuron were sampled along railroad rights-of-way in north dakota and minnesota. the samples were screened in the greenhouse for resistance to diuron, tebuthiuron, metribuzin and bromoxynil from 0.5x to 32x the recommended use rates. a resistant k scoparia accession (mn ...200515952238
an easy and rapid method using microscopy to determine herbicide effects in poaceae weed species.a new, easy, rapid and relatively inexpensive method using microscopy has been developed for the detection of herbicide effects in leaves of grass weed species displaying no visual signs of damage. the method has potential to be used as a tool to indicate future death of grass species due to herbicide exposure by observing phytochemical effects, i.e. early-warning effects. in the present study, apera spica-venti (l.) beauv., bromus hordeaceus l., alopecurus myosuroides huds., lolium perenne l. a ...200616628541
suitability of various turfgrass species and cultivars for development and survival of black cutworm (lepidoptera: noctuidae).black cutworm, agrotis ipsilon (hufnagel) (lepidoptera: noctuidae), feeding bioassays were conducted on young and mature turfgrass species to determine their potential resistance. measures of resistance included larval weight, survival rate, instar development, pupal weight, duration of pupation, and days to pupation and adult emergence. black cutworm reared on poa pratensis 'midnight', poa arachnigera 'tejas', and poa pratensis x poa arachnigera 'reveille' exhibited slower development, lower we ...200616813321
assessing determinants of community biomass composition in two-species plant competition studies.a method is proposed for assessing the relative importance of species identity, neighbour species influence and environment as determinants of change in community biomass composition in two-species short-term competition experiments. the method is based on modelling the differences in relative growth rates (rgr) of species (hence called the rgrd method). using a multiple regression approach it quantifies the effects of initial species' abundance, species identity and environment on rgrd and henc ...200415655692
effects of traffic pollution on the genetic structure of poa annua l. populations.the genetic composition of poa annua l. populations with a series of traffic pollution was studied by starch electrophoresis. five enzyme systems were stained. the results showed that: (1) traffic pollution can dramatically change genotypic frequencies at some loci of p. annua populations. significant deviations from hardy-weinberg equilibrium were observed on loci fe-1 and me due to the excess of heterozygotes in some populations. (2) the effective number of alleles per locus and the observed a ...200415272722
4-formylaminooxyvinylglycine, an herbicidal germination-arrest factor from pseudomonas rhizosphere bacteria.a new oxyvinylglycine has been identified as a naturally occurring herbicide that irreversibly arrests germination of the seeds of grassy weeds, such as annual bluegrass (poa annua), without significantly affecting the growth of established grass seedlings and mature plants or germination of the seeds of broadleaf plant species (dicots). previously, pseudomonas fluorescens wh6 and over 20 other rhizosphere bacteria were isolated and selected for their ability to arrest germination of p. annua se ...201020979386
[allelopathy of aqueous extract from ligularia virgaurea, a dominant weed in psychro-grassland, on pasture plants].ligularia virgaurea is a noxious weed widely distributed in the alpine grassland of east qinghai-tibet plateau of china. this paper studied the allelopathy of its aqueous extract on the pasture plants festuca sinensis, bromus magnus, elymus nutans, poa annua, and f. ovina in the region. the mean response index (ri) values of the pasture plants were calculated, and used to quantitatively assess the allelopathic sensitivity of the receptors at three levels, i. e., growth items, development stages, ...200616883813
use of plant cell cultures to study graminicide effects on lipid metabolism.graminicides belonging to the cyclohexanedione and aryloxyphenoxypropionate classes are well established to act by disrupting acyl lipid biosynthesis via specific inhibition of acetyl-coa carboxylase. species of grass inherently resistant to such herbicides, or biotypes of grassy weed species which display acquired resistance to recommended rates of graminicide application, are known to possess an altered plastidic multifunctional acetyl-coa carboxylase showing reduced sensitivity to these herbi ...200312809713
relative contributions of leaf area ratio and net assimilation rate to change in growth rate depend on growth temperature: comparative analysis of subantarctic and alpine grasses.the present study shows that the relative contributions of leaf area ratio (lar) and net assimilation rate (nar) to variation among species in relative growth rate (rgr) depend on growth temperature. we grew three subantarctic and three alpine poa species at daytime temperatures of 7, 12 and 17 degrees c, and analysed interspecific and temperature-related variation in rgrs by growth analysis. variation in nar accounted for most of the interspecific differences in rgr at low growth temperature, w ...200717587377
antagonistic interactions between plant competition and insect herbivory.interspecific competition between plants and herbivory by specialized insects can have synergistic effects on the growth and performance of the attacked host plant. we tested the hypothesis that competition between plants may also negatively affect the performance of herbivores as well as their top-down effect on the host plant. in such a case, the combined effects of competition and herbivory may be less than expected from a simple multiplicative response. in other words, competition and herbiv ...200717601141
uptake of heavy metals by native species growing in a mining area in sardinia, italy: discovering native flora for phytoremediation.this study assessed the distribution and availability of plant uptake of zn, pb, and cd present in an abandoned mine at ingurtosu, sardinia (italy). geological matrix samples (sediments, tailings, and soil from a nearby pasture site) and samples of the predominant plant species growing on sediments and tailings were collected. mean values of total zn, pb and cd were respectively (mg kg(-1)) 7400, 1800, and 56 in tailings, 31000, 2900, and 100 in sediments, and 400, 200, and 8 in the pasture soil ...201121972566
distribution, abundance, and seasonal ecology of listronotus maculicollis (coleoptera: curculionidae) on golf courses in québec, canada.the weevil listronotus maculicollis dietz (coleoptera: curculionidae) is a major pest of annual bluegrass, poa annua l., on golf courses in northeastern north america. to determine the distribution, abundance, and seasonal ecology of l. maculicollis on golf courses in québec, canada, we sampled 19 golf courses (gc1-gc19) from different geographic and climatic conditions during 2001, 2002, and 2003. l. maculicollis was found on all golf courses except gc19, which was located in northeastern québe ...200717849888
spatial and temporal patterns of carabid activity-density in cereals do not explain levels of predation on weed seeds.seed predation is an important component of seed mortality of weeds in agro-ecosystems, but the agronomic use and management of this natural weed suppression is hampered by a lack of insight in the underlying ecological processes. in this paper, we investigate whether and how spatial and temporal variation in activity-density of granivorous ground beetles (coleoptera: carabidae) results in a corresponding pattern of seed predation. activity-density of carabids was measured by using pitfall traps ...200818076785
trace elements in wild grasses: a phytoavailability study on a remediated field.there have been significant efforts to establish a widely usable method for the prediction of trace element bioavailability in soil. in this work, we used extraction with 0.01 m cacl2 and 0.05 m ethylenediaminetetraacetic acid (edta) to estimate bioavailable concentrations of as, cd, cu, pb, and zn in a soil moderately contaminated with trace elements 1 and 2 years after the application of three amendments. the experiment took place in a field plot of a soil affected by the toxic spill of the az ...200818253844
studies on land application of sewage sludge and its limiting factors.field experiments were conducted to study the effect of sewage sludge application on the heavy metal content in soils and grasses. the sewage sludge was obtained from northern shenyang wastewater treatment plant, china, and applied at 0, 15, 30, 60, 120 and 150tha(-1). native grasses zoysia japonica and poa annua were chosen as experimental plants. the experimental results showed that nutrient content of the soil, especially organic matter, was increased after sewage sludge application. the gras ...200818456400
development of a field bioassay for the side-effects of herbicides on vascular plants using brassica napus and poa annua.a field bioassay method has been developed for assessing side-effects of herbicides on brassica napus and poa annua. the test method aims at effects outside the target area, up to 20 m from the treated parcel. experiments were conducted in the field and in a glasshouse with the herbicides atrazin, bentazone, diquat, glyphosate, and r(4-chloro-2-methylphenoxyacetic acid) mcpa. an iterative procedure was used with the aim of developing a sound test procedure. the resulting method appeared to be ve ...200111594026
evidence from action and fluorescence spectra that uv-induced violet-blue-green fluorescence enhances leaf photosynthesis.we assessed the contribution of uv-induced violet-blue-green leaf fluorescence to photosynthesis in poa annua, sorghum halepense and nerium oleander by measuring uv-induced fluorescence spectra (280-380 nm excitation, 400-550 nm emission) from leaf surfaces and determining the monochromatic uv action spectra for leaf photosynthetic o2-evolution. peak fluorescence emission wavelengths from leaf surfaces ranged from violet (408 nm) to blue (448 nm), while excitation peaks for these maxima ranged f ...200111281021
patterns of variation in the seasonal dynamics of listronotus maculicollis (coleoptera: curculionidae) populations on golf course turf.listronotus maculicollis (kirby) is a burgeoning pest of poa annua l. in the northeast united states. to develop an understanding of its spatial and temporal association with golf course landscapes, we described the patterns of variation in certain population parameters across site (fayetteville and ithaca, ny), year (2004-2006), and management habitat (fairway, intermediaterough, rough). in weekly surveys along fairway transects, we sampled larvae (identified to instar) by soil core extraction ...200819161687
characteristics of chloroplast thylakoid lipid composition associated with resistance to triazine herbicides.a detailed comparison of the polar-lipid composition of chloroplast thylakoid membranes isolated from triazine-susceptible and triazine-resistant biotypes of chenopodium album, senecio vulgaris, poa annua and amaranthus retroflexus has been carried out. no major differences in the composition of the bulk lipid matrix were found except for a slightly higher monogalactosyldiacylglycerol to digalactosyldiacylglycerol ratio in resistant compared with susceptible biotypes. there was, however, in the ...198524241445
strategies to use phytoextraction in very acidic soil contaminated by heavy microcosm experiments, the use of inorganic and organic amendments has been studied as potential agents to reduce heavy metal bioavailability in an acidic soil highly contaminated by cu, zn and ni, that has to be remediated by phytoremediation. the concentrations of heavy metals in the original soil (o-soil) produced phytotoxic effects with a strong reduction in biomass yield that hinder the utilization of this technology. to overcome phytotoxicity the use of three immobilizing agents was eva ...200919217142
avermectin b1, isazofos, and fenamiphos for control of hoplolaimus galeatus and tylenchorhynchus dubius infesting poa annua.avermectin b, isazofos, and fenamiphos were evaluated in greenhouse experiments for efficacy against two common turfgrass parasites, hoplolaimus galeatus and tylenchorhynchus dubius. treatments in all experiments were arranged in a completely randomized design and replicated four times. in the first experiment, avermectin b at rates of 0.2 and 0.4 kg a.i./ha and isazofos at rates of 2.3 and 23 kg a.i./ha significantly reduced populations of both species of parasitic nematodes compared to control ...199619277196
root growth of bentgrass and annual bluegrass as influenced by coinfection with tylenchorhynchus nudus and magnaporthe poae.a study was conducted in growth chambers to examine main factor and interaction effects of tylenchorhynchus nudus and magnaporthe poae on creeping bentgrass and annual bluegrass at 24, 28, and 30 c. a 2 x 2 factorial arrangement of treatments was employed with presence and absence of t. nudus and m. poae as factors with each temperature run separately for 14 or 18 days. tylenchorhynchus nudus decreased bentgrass and annual bluegrass root length at all three temperatures. magnaporthe poae had no ...199419279874
population fluctuations of three nematode genera in putting greens in northern illinois.field experiments were conducted in 1989 and 1990 to examine the population fluctuation patterns of tylenchorhynchus nudus, criconemella curvata, and helicotylenchus cornurus in mixed bentgrass and annual bluegrass putting greens on two golf courses near chicago, illinois, to determine if fluctuation patterns could be extrapolated to unsampled greens. fenamiphos-treated and untreated plots were established on seven putting greens on two golf courses. greens were sampled intensively five times du ...199419279925
virulence of xanthomonas translucens pv. poae isolated from poa annua.bacterial wilt is a vascular wilt disease caused by xanthomonas translucens pv. poae that infects poa annua, a grass that is commonly found on golf course greens throughout the world. bacterial wilt causes symptoms of etiolation, wilting, and foliar necrosis. the damage is most prevalent during the summer and the pathogen can kill turf under conditions optimal for disease development. fifteen isolates of x. translucens pv. poae were collected from northern regions in the united states and tested ...201325288933
the brighter side of soils: quantum dots track organic nitrogen through fungi and plants.soil microorganisms mediate many nutrient transformations that are central in terrestrial cycling of carbon and nitrogen. however, uptake of organic nutrients by microorganisms is difficult to study in natural systems. we assessed quantum dots (fluorescent nanoscale semiconductors) as a new tool to observe uptake and translocation of organic nitrogen by fungi and plants. we conjugated quantum dots to the amino groups of glycine, arginine, and chitosan and incubated them with penicillium fungi (a ...200919294917
multiple host-plant use may arise from gender-specific fitness effects.ovipositing females are predicted to select host-plants that will maximise offspring survival and fitness. yet hosts often differ in the component of larval fitness affected so host-selection often involves a trade-off between short development times and large size and high fecundity of offspring. if host-species can directly affect development rates and body size, and if there are gender differences in resource allocation during development, there can be different sex-specific selection pressur ...200619537967
selecting tolerant grass seedlings and analyzing the possibility for using aged refuse as sward order to test the possibility for recycling use of aged refuse as sward soil, the study determined the responses of lolium perenne l. (perennial ryegrass), festuca arundinacea (tall fescue), and poa annua (annual bluegrass) to its leaching. the growth of three seedlings was significantly inhibited after treatment, especially for longer treatment duration and higher concentration leaching; however, with the better growth and chlorophyll content for shorter time and lower concentration, tall fe ...201020036424
plants growing on contaminated and brownfield sites appropriate for use in organisation for economic co-operation and development terrestrial plant growth test.the organisation for economic co-operation and development (oecd) terrestrial plant test is often used for the ecological risk assessment of contaminated land. however, its origins in plant protection product testing mean that the species recommended in the oecd guidelines are unlikely to occur on contaminated land. six alternative species were tested on contaminated soils from a former zn smelter and a metal fragmentizer with elevated concentrations of cd, cu, pb, and zn. the response of the al ...201120853450
a global analysis of the impacts of urbanization on bird and plant diversity reveals key anthropogenic drivers.urbanization contributes to the loss of the world's biodiversity and the homogenization of its biota. however, comparative studies of urban biodiversity leading to robust generalities of the status and drivers of biodiversity in cities at the global scale are lacking. here, we compiled the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities). we found that the majority of urban bird and plant species are native in the world's cities. few plants ...201424523278
collaboration between grass seedlings and rhizobacteria to scavenge organic nitrogen in soils.plants require nitrogen (n) to make proteins, nucleic acids and other biological molecules. it is widely accepted that plants absorb inorganic forms of n to fill their needs. however, recently it has become clear that plants also have the capacity to absorb organic n from soils. in this paper we describe a new kind of symbiosis involving seed-vectored rhizobacteria and grasses that is targeted at enhancing acquisition of organic n from soils. our proposal is based on results of experiments on se ...201525564515
taxonomy and postembryonic stages of the nematode predator odontopharynx longicaudata de man, 1912 (diplogasterida).odontopharynx longicaudata (diplogasterida: odontopharyngidae) was found in soil around roots of poa annua l. growing on a golf course in san francisco, california. this is the first record of this species in the united states. populations of o. longicaudata were increased in the laboratory on the free-living nematode ucd acrobeloides no. 1 (rhabditida: cephalobidae). light microscopy was used to compare the morphology of fixed specimens from california and the netherlands. california specimens ...198919287598
studies on the host range, biology, and pathogenicity of punctodera punctata infecting turfgrasses.punctodera punctata completed its life cycle on poa annua (annual bluegrass), p. pratensis (merion kentucky bluegrass), lolium perenne (perennial ryegrass), and festuca rubra rubra (spreading fescue). minimum time for completion of a life cycle from second-stage juvenile to mature brown cyst was 40 days at 22-28 c. inoculation by single juveniles indicated that reproduction was most likely by amphimixis. infestation levels of 50 or 500 juveniles/250 cm(3) soil did not affect top dry weight, root ...198519294077
allelopathic potential of invasive plantago virginica on four lawn species.plantago virginica l. has invaded many lawn ecosystems in the eastern part of china. the invasion has incurred an economic cost to remove them. in order to prevent the invasion, it is critical to understand the invasive mechanisms of this species. however, few studies have been conducted on the allelopathic mechanisms of its invasion. in this study, we examined allelopathic effects of p. virginica on germination of seeds and growth of seedlings of four widely used lawn species. we found extensiv ...201525915515
distribution, biology and pathology of anguina pacificae.anguina pacificae is distributed along a narrow strip on the pacific coast of northern california where it forms galls on the shoots of poa annua and causes significant damage to golf course greens. methods were developed for the continuous propagation of a. pacificae on p. annua in growth chambers, and they were used to examine the life cycle and host-parasite relationships of the nematode. at a mean temperature of 20 degrees c (22 degrees c day/18 degrees c night) the life cycle was completed ...200819440264
physiological effects of temperature on turfgrass tolerance to amicarbazone.amicarbazone effectively controls annual bluegrass (poa annua l.) in bermudagrass [cynodon dactylon (l.) pers. × c. transvaalensis burtt-davy] and tall fescue (festuca arundinacea schreb.) with spring applications, but summer applications may excessively injure tall fescue. the objective of this research was to investigate physiological effects of temperature on amicarbazone efficacy, absorption, translocation and metabolism in annual bluegrass, bermudagrass and tall fescue.201525045054
development of binomial sequential sampling plans for forecasting listronotus maculicollis (coleoptera: curculionidae) larvae based on the relationship to adult counts and turfgrass damage.binomial sequential sampling plans were developed to forecast weevil listronotus maculicollis kirby (coleoptera: curculionidae), larval damage to golf course turfgrass and aid in the development of integrated pest management programs for the weevil. populations of emerging overwintered adults were sampled over a 2-yr period to determine the relationship between adult counts, larval density, and turfgrass damage. larval density and composition of preferred host plants (poa annua l.) significantly ...200919610454
developmental toxicity assessment of the new turf herbicide, methiozolin ([5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3,3(3-methylthiophen-2-yl)-1,2-isoxazoline]), in rabbits.methiozolin is a new herbicide to control annual bluegrass (poa annua l.) and large crabgrass (digitaria sanguinalis (l.) scop.) in various turfgrasses. the potential of methiozolin to induce maternal and developmental toxicity was investigated in the pregnant new zealand white rabbits. methiozolin was, at dose levels of 0, 125, 250 and 500 mg/kg/day, administered by oral gavage to artificially inseminated rabbits (25 females per group) from days 6 to 28 of gestation. all does were subjected to ...201526003517
exposure to cadmium-contaminated soils increases allergenicity of poa annua l. pollen.pollution is considered as one main cause for the increase of allergic diseases. air pollutants may cause and worsen airway diseases and are probably able to make pollen allergens more aggressive. previous studies looked at traffic-related air pollution, but no data about the effects of polluted soils on pollen allergens are available. we aimed to assess the effects of plant exposure to cadmium-contaminated soil on allergenicity of the annual blue grass, poa annua l, pollen.201020374228
the influence of weed-cover on the mortality imposed on artificial prey by predatory ground beetles in cereal fields.pitfall trapping was carried out in a field of winter wheat in the vale of york to determine the levels of abundance of adult carabid and staphylinid beetles, (which formed the bulk of the natural predator complex) in the field. a point quadrat survey was carried out at the same time to assess the vegetation cover round each trap. predation pressure by the beetles in the field was monitored using fruit fly (drosophila) pupae as artificial prey. these artificial prey were attached to small cards ...197628308927
synergism between demethylation inhibitor fungicides or gibberellin inhibitor plant growth regulators and bifenthrin in a pyrethroid-resistant population of listronotus maculicollis (coleoptera: curculionidae).in 2007-2008, the "annual bluegrass weevil," listronotus maculicollis kirby (coleoptera: curculionidae), a serious pest of poa annua l. (poales: poaceae) on u.s. golf courses, was shown to be resistant to two pyrethroids, bifenthrin and lambda-cyhalothrin. in 2008, we showed that bifenthrin resistance was principally mediated by oxidase detoxification (cytochrome p450 [p450]). p450s can be inhibited by demethylation inhibitor fungicides and gibberellin inhibitor plant growth regulators, both of ...201021061984
cold-induced responses in annual bluegrass genotypes with differential resistance to pink snow mold (microdochium nivale).greens-type annual bluegrass (poa annua l.) is susceptible to winter stresses including subfreezing temperatures and pink snow mold (sm). to better understand the mechanisms of sm resistance in annual bluegrass, four sm-resistant and four sm-sensitive genotypes were incubated at low temperature with microdochium nivale (fries) samuels & hallett, the causal agent of pink snow mold. we assessed the impact of a 6-week incubation period with sm at 2 °c under high humidity (≥ 98%) on the accumulation ...201121421353
metal contamination of soils and plants associated with the glass industry in north central india: prospects of phytoremediation.introduction: the effect of the glass industry on urban soil metal characterization was assessed in the area of firozabad, india. a comprehensive profile of metal contamination was obtained in five zones each containing five specific sites. findings: zn, cd, and as showed a greater accumulation, whereas accumulation of ni and cu was high in limited samples. positive correlation was found for the metal pairs cu-zn, cu-co, and cu-cr at pôçë<ôçë0.01. moderate positive correlation was also observed ...201121735162
Interactive effects of plant-available soil silicon and herbivory on competition between two grass species.The herbivore defence system of true grasses (Poaceae) is predominantly based on silicon that is taken up from the soil and deposited in the leaves in the form of abrasive phytoliths. Silicon uptake mechanisms can be both passive and active, with the latter suggesting that there is an energetic cost to silicon uptake. This study assessed the effects of plant-available soil silicon and herbivory on the competitive interactions between the grasses Poa annua, a species that has previously been repo ...201121868406
the pseudomonas aeruginosa antimetabolite l-2-amino-4-methoxy-trans-3-butenoic acid inhibits growth of erwinia amylovora and acts as a seed germination-arrest factor.the pseudomonas aeruginosa antimetabolite l-2-amino-4-methoxy-trans-3-butenoic acid (amb) shares biological activities with 4-formylaminooxyvinylglycine, a related molecule produced by pseudomonas fluorescens wh6. we found that culture filtrates of a p. aeruginosa strain overproducing amb weakly interfered with seed germination of the grassy weed poa annua and strongly inhibited growth of erwinia amylovora, the causal agent of the devastating orchard crop disease known as fire blight. amb was ac ...201223757135
development of a greenhouse-based inoculation protocol for the fungus colletotrichum cereale pathogenic to annual bluegrass (poa annua).the fungus colletotrichum cereale incites anthracnose disease on poa annua (annual bluegrass) turfgrass. anthracnose disease is geographically widespread throughout the world and highly destructive to cool-season turfgrasses, with infections by c. cereale resulting in extensive turf loss. comprehensive research aimed at controlling turfgrass anthracnose has been performed in the field, but knowledge of the causal organism and its basic biology is still needed. in particular, the lack of a reliab ...201526339538
influence of host and geographic locale on the distribution of colletotrichum cereale lineages.colletotrichum cereale is an ascomycete inhabitant of cool-season pooideae grasses. the fungus has increased in frequency over the past decade as a destructive pathogen of poa annua and agrostis stolonifera turfgrass. colletotrichum cereale exists as two lineages, designated clades a and b, but little is known about the distribution of these clades in natural environments, or what role these subdivisions may play in the trajectory of disease outbreaks. in this study, our objective was to determi ...201424842654
responses of poa annua and three bentgrass species (agrostis spp.) to adult and larval feeding of annual bluegrass weevil, listronotus maculicollis (coleoptera: curculionidae).the annual bluegrass weevil (abw), listronotus maculicollis kirby, is an economically important pest of short-cut turfgrass in eastern north america. wide spread insecticide resistance warrants the development of alternative management strategies for this pest. abw damage typically occurs in areas with a high percentage of annual bluegrass, poa annua l., the preferred abw host. damage to bentgrasses, agrostis spp., is much rarer and usually less severe. to aid the implementation of host plant re ...201627353253
short-term variability of plant populations within a regularly disturbed habitat.the changing populations of weeds during 13 years of the broadbalk continuous wheat experiment were analysed to investigate the extent of differences in shortterm variability of cover between species. the data were from two sections of the experiment where winter wheat was grown continuously under herbicide treatment for 13 and 6 years respectively. logistic regressions were fitted to the data. equisetum arvense showed significant long-term increases on both sections; long-term trends were also ...199328313670
indaziflam herbicidal action: a potent cellulose biosynthesis inhibitor.cellulose biosynthesis is a common feature of land plants. therefore, cellulose biosynthesis inhibitors (cbis) have a potentially broad-acting herbicidal mode of action and are also useful tools in decoding fundamental aspects of cellulose biosynthesis. here, we characterize the herbicide indaziflam as a cbi and provide insight into its inhibitory mechanism. indaziflam-treated seedlings exhibited the cbi-like symptomologies of radial swelling and ectopic lignification. furthermore, indaziflam in ...201425077797
phytotoxic allelochemicals from roots and root exudates of trifolium pratense.trifolium pratense, a widespread legume forage plant, is reported to exhibit phytotoxic activity on other plants, but the active metabolites have not been clarified so far. a bioassay-guided fractionation of the root extracts led to the isolation of five isoflavonoids, which were elucidated by spectroscopic analysis. all of the purified compounds observably showed phytotoxic activities against arabidopsis thaliana . moreover, the inhibitory effects were concentration-dependent. the furan ring li ...201323738849
variations of leaf cuticular waxes among c3 and c4 gramineae herbs.modern c4 plants are commonly distributed in hot and dry environments whereas c3 plants predominate in cool and shade areas. at the outmost of plant surface, the deposition and chemical composition of cuticular waxes vary under different environmental conditions. however, whether such variation of cuticular wax is related to the distribution of c3 and c4 under different environmental conditions is still not clear. in this study, leaves of six c3 gramineae herbs distributed in spring, roegneria k ...201627563829
[plant communities in the terrestrial-aquatic transition zone in the paramo of chingaza, colombia].plant communities in the terrestrial-aquatic transition zone in the paramo of chingaza, colombia. high andean paramo ecosystems are an important water resource for many towns, and major cities in this region. the aquatic and wetland vegetation of different paramo lakes, pond, swamps and bogs was studied according to the classical phytosociological approach, which is based on homogenous stands, but excludes any border phenomena or transitional zone. the present research aimed at determining the a ...201222458208
enantioselective phytotoxicity and bioacitivity of the enantiomers of the herbicide napropamide.enantioselectivity of chiral pesticide enantiomers should be taken into consideration in pesticide application and environmental risk assessment. the phytotoxicity of the enantiomers of napropamide to cucumber, soybean, and the bioactivity to the target weeds poa annua and festuca arundinacea have been studied in this work. to the nontarget crops, the influences of napropamide on the root, shoot, fresh weight, chlorophyll, superoxide dismutase (sod) and catalase (cat) activities and membrane lip ...201526615149
allelochemicals in the rhizosphere soil of euphorbia himalayensis.weed infestation has been known to cause considerable reductions in crop yields, thereby hindering sustainable agriculture. many plants in genus euphorbia affect neighboring plants and other organisms by releasing chemicals into the environment. in view of the serious threat of weeds to agriculture, the allelochemicals of euphorbia himalayensis and their allelopathic effects were investigated. the extract of root exudates from rhizosphere soil exhibited allelopathic activities against crops (whe ...201425088250
towards a transferable and cost-effective plant aflp protocol.amplified fragment length polymorphism (aflp) is a powerful fingerprinting technique that is widely applied in ecological and population genetic studies. however, its routine use has been limited by high costs associated with the optimization of fluorescently labelled markers, especially for individual study systems. here we develop a low-cost aflp protocol that can be easily transferred between distantly related plant taxa. three fluorescently labelled ecori-primers with anchors that target int ...201323613908
the effect of nitrate-nitrogen supply on bacteria and bacterial-feeding fauna in the rhizosphere of different grass species.microbial growth in the rhizosphere is affected by the release of organic material from roots, so differences in carbon budgets between plants may affect their rhizosphere biology. this was tested by sampling populations of bacteria and bacteriophagous fauna from the rhizosphere of lolium perenne, festuca arundinacea, poa annua, and poa pratensis, under conditions of high and low nitrate availability. concentrations of soluble phenolics and lignin varied considerably between the species but were ...199228313466
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