Holcus Lanatus Research Articles

Adaptation to acidic soil is achieved by increased numbers of cis‐acting elements regulating ALMT1 expression in Holcus lanatus

Yorkshire fog (Holcus lanatus), which belongs to the Poaceae family and is a close relative of the agronomic crop oat (Avena sativa), is a widely adaptable grass species that is able to grow on highly acidic soils with high levels of Al, but the mechanism underlying the high Al tolerance is unknown. Here, we characterized two accessions of H.lanatus collected from an acid plot (soil pH 3.6, HL-A) and a neutral plot (pH 7.1, HL-N) in terms of Al tolerance, organic acid anion secretion and related gene expression. In response to Al (pH 4.5), the HL-A roots secreted approximately twice as much malate as the HL-N roots, but there was no difference in citrate secretion. Cloning of the gene HlALMT1 responsible for malate secretion showed that the encoded amino acid sequence did not differ between two accessions, but the expression level in the outer cell layers of the HL-A roots was twice as high as in the HL-N roots. This difference was not due to the genomic copy number, but was due to the number of cis-acting elements for an Al-responsive transcription factor (HlART1) in the promoter region of HlALMT1, as demonstrated by both a yeast one-hybrid assay and a transient assay in tobacco protoplasts. Furthermore, introduction of HlALMT1 driven by the HL-A promoter into rice resulted in significantly more Al-induced malate secretion than introduction of HlALMT1 driven by the HL-N promoter. These findings indicate that the adaptation of H.lanatus to acidic soils may be achieved by increasing number of cis-acting elements for ART1 in the promoter region of the HlALMT1 gene, enhancing the expression of HlALMT1 and the secretion of malate.

Nutritive value, in vitro fermentation and methane production of perennial pastures as affected by botanical composition over a growing season in the south of Chile

Permanent pastures have been shown to produce similar herbage masses and nutrient contents to perennial ryegrass pastures. To the best of our knowledge, little research has been conducted on the ruminal fermentation of permanent pastures. Our objective was to evaluate the effect of botanical composition of four perennial pastures during a growing season in the south of Chile [winter, September 2010 ‘S1’; spring, November 2010 ‘S2’; and summer, January 2011 ‘S3’]: on in vitro fermentation products using a batch culture system. The perennial pastures studied included: permanent (PP), permanent fertilised (PFP) and renovated pastures (Lolium perenne and Trifolium repens pasture ‘RGWC’; Bromus valdivianus, Dactylis glomerata, Holcus lanatus, L. perenne and T. repens ‘MIXED’). There were strong interactions between pasture type and regrowth period for true organic matter, nitrogen (N) and neutral detergent fibre digestibility; total gas and volatile fatty acid (VFA) production; ammonia and microbial N. In general, all pasture treatments showed a high true organic matter digestibility (>800 g/kg), and tended to decrease in S3. In vitro fermentation of PFP and RGWC produced the highest total VFA concentration during S1 and S2, and no differences among pastures were observed in summer. Propionate proportion of total VFA was affected by pasture type and regrowth period, being higher for RGWC and S1, respectively. In vitro microbial N was higher for MIXED in S1, and PFP in S2 and S3. No pasture and regrowth period effects were observed for methane production and its proportion of total gas production. These results indicate that the in vitro fermentation products of a permanent fertilised pasture reach similar levels to those obtained from a sown pasture, and thus may be considered as a sustainable alternative for grazing livestock systems.

Seasonal dynamics in understorey abundance and carbohydrate concentration in relation to browsing and bark stripping of Tasmanian Pinus radiata plantations

Bark stripping in Pinus radiata plantations by Bennett’s wallaby (M. rufrogriseus subspecies rufrogriseus) triggers high rates of tree mortality and reduces crop productivity, causing significant economic losses to the Australian forest industry. Bark stripping shows a marked increase during winter which may be associated with concurrent increases in bark soluble sugar concentration. Seasonal abundance of alternative forage may also contribute to bark-stripping incidence. Relationships between seasonal variations in forage quantity and quality, and periods of increased bark stripping were assessed in two P. radiata plantations. Understorey composition, abundance, browsing pressure, and sugar, starch and total non-structural carbohydrate (TNC) concentrations were measured seasonally over a period of 12months for each species in areas experiencing high and low levels of bark stripping. A strong general positive association of high soluble sugar concentrations, particularly in two exotic grasses Poa annua and Holcus lanatus, with elevated levels of browsing pressure was found. In contrast starch content was weakly and negatively associated with browsing pressure. Ratios of the concentration of soluble sugars to starch were significantly and positively correlated with browsing pressure. Understorey species were allocated to five sub-groups based on putative chemical and physical mechanisms of tolerance to, or defence against, herbivory. This sub-grouping lends support to the significant effect of sugar to starch ratios on browsing preference. The current study demonstrates that soluble sugar concentration of P. radiata bark was consistently higher than concentrations in native understorey species and that bark represents an available, apparent and high quality food source to wallaby. P.annua and H. lanatus had comparable concentrations of soluble sugars to P. radiata bark and are an alternative food source provided they remain in sufficient abundance. These results are indicative of a key mechanism driving bark stripping in Tasmania. The results lend credence to the implementation of two browser management strategies (1) in the short term, the provision of a diversionary feed and (2) limiting the abundance of alternative herbage so that over time the plantation landscape supports lower populations of browsers.

Effects of waterlogging on the solubility and redox state of Sb in a shooting range soil and its uptake by grasses: a tank experiment

AimsThe effects of waterlogging on redox state and solubility of antimony (Sb) in a calcareous shooting range soil and its uptake by forage grass Lolium perenne L. and pasture weed Holcus lanatus L. were investigated.MethodsGrasses were grown on semi-waterlogged or waterlogged shooting range soil in a laboratory tank. The soil solution was sampled at various depths over time and analyzed for the concentrations of Sb(III), Sb(V) and total Sb, as well as other trace elements.ResultsAlthough the reduction of Sb(V) to Sb(III) under increased waterlogging time decreased Sb solubility, it increased Sb uptake by L. perenne from 1.1 to 1.7 mg kg−1 (and to a lesser extent H. lanatus), implying preferential uptake of Sb(III) by this grass. The tank showed considerable variation in redox conditions with depth and plant treatment. The soil root zone (30 cm for L. perenne and 15 cm for H. lanatus) instead of the water saturated bottom, showed the highest manganese (Mn) and iron (Fe) concentrations in solution, accompanied by a higher proportion of Sb(III) in solution than the bottom zone of the tank.ConclusionsWaterlogging can increase the risk of Sb entering the food chain from shooting range soil.

Identity of Schizaphis species (Hemiptera: Aphididae) in the United Kingdom: are they a threat to crops?

The greenbug, Schizaphis graminum (Rondani), is a major pest of cereals in some parts of the world and is of particular concern because it can be resistant to some insecticides and overcome the resistance of crops. In the UK, it has never been found on crops, but two rather little-known and closely-related species (Schizaphis holci and Schizaphis agrostis) are associated with the wild grasses, Holcus lanatus and Agrostis stolonifera. Since 1987, winged (alate) aphids morphologically resembling the greenbug have been found in increasing numbers in 12.2m high suction-trap samples of the Rothamsted Insect Survey (RIS); hence, studies were undertaken to establish their identity. Clones (=asexual lineages) established from populations collected from H. lanatus in southern England showed strong preference for Holcus over Agrostis and Hordeum in laboratory tests and produced sexual morphs when transferred to short-day conditions, the males being apterous, as expected for S. holci. Multivariate morphometric comparisons of alatae caught in UK RIS suction traps in 2007 and 2011 with named specimens from museum collections, including S. graminum from many countries, indicated that the suction-trapped alatae were mostly S. agrostis and S. holci. Cytochrome c oxidase subunit I (COI) mtDNA obtained from 62 UK specimens from suction-traps had 95.4-100% sequence identity with US specimens of S. graminum. Two of the UK specimens had identical COI sequence to the US sorghum-adapted form of S. graminum, and these specimens also had 100% identity with a 640bp fragment of nDNA CytC, indicating that this form of S. graminum may already be present in the UK. Present and future economic implications of these results are discussed.

The root herbivore history of the soil affects the productivity of a grassland plant community and determines plant response to new root herbivore attack.

Insect root herbivores can alter plant community structure by affecting the competitive ability of single plants. However, their effects can be modified by the soil environment. Root herbivory itself may induce changes in the soil biota community, and it has recently been shown that these changes can affect plant growth in a subsequent season or plant generation. However, so far it is not known whether these root herbivore history effects (i) are detectable at the plant community level and/or (ii) also determine plant species and plant community responses to new root herbivore attack. The present greenhouse study determined root herbivore history effects of click beetle larvae (Elateridae, Coleoptera, genus Agriotes) in a model grassland plant community consisting of six common species (Achillea millefolium, Plantago lanceolata, Taraxacum officinale, Holcus lanatus, Poa pratensis, Trifolium repens). Root herbivore history effects were generated in a first phase of the experiment by growing the plant community in soil with or without Agriotes larvae, and investigated in a second phase by growing it again in the soils that were either Agriotes trained or not. The root herbivore history of the soil affected plant community productivity (but not composition), with communities growing in root herbivore trained soil producing more biomass than those growing in untrained soil. Additionally, it influenced the response of certain plant species to new root herbivore attack. Effects may partly be explained by herbivore-induced shifts in the community of arbuscular mycorrhizal fungi. The root herbivore history of the soil proved to be a stronger driver of plant growth on the community level than an actual root herbivore attack which did not affect plant community parameters. History effects have to be taken into account when predicting the impact of root herbivores on grasslands.

INFLUENCE OF SOIL PROPERTIES AND PHOSPHATE ADDITION ON ARSENIC UPTAKE FROM POLLUTED SOILS BY VELVETGRASS (HOLCUS LANATUS)

Four kinds of soil material were used in a pot experiment with velvetgrass (Holcus lanatus). Two unpolluted soils: sand (S) and loam (L) were spiked with sodium arsenite (As III) and arsenate (As V), to obtain total arsenic (As) concentrations of 500 mg As kg−1. Two other soils (ZS I, ZS III), containing 3320 and 5350 mg As kg−1, were collected from Zloty Stok where gold and arsenic ores were mined and processed for several centuries. The effects of phosphate addition on plants growth and As uptake were investigated. Phosphate was applied to soils in the form of NH4H2PO4 at the rate 0.2 g P/kg. Average concentrations of arsenic in the shoots of velvetgrass grown in spiked soils S and L without P amendment were in the range 18–210 mg As kg−1 d.wt., whereas those in plants grown on ZS I and ZS II soils were considerably lower, and varied in the range 11–52 mg As kg−1 d.wt. The addition of phosphate caused a significant increase in plant biomass and therefore the total amounts of As taken up by plants, however, the differences in As concentrations in the shoots of velvetgrass amended and non-amended with phosphate were not statistically significant.

Effects of nitrogen fertilization on β-caroten content in meadow plants

β-caroten content was estimated in the leaves of <em>Alopecurus pratensis, Festuca rubra, Festuca pratensis, Holcus lanatus, Poa pratensis, Carex hirta, Carex Hudsonii</em> <em>and Plantago lanceolata</em> from two different meadows on which different nitrogen fertilization and uniform phosphorus and potassium fertilization were applied. Nitrogen fertilization was found to affect the accumulation of β-caroten in plants.

The share of roots, sward and stubble biomass in biological yield of selected grass species

In this study assessed the share of harvested yield and share of root stem bases and stolon biomass in biological yield of 6 grass species grown in pure sowing. The biological yield included harvested yield from 3 regrowth and biomass of RSS (roots, sward and stubble), which was taken after 3th cut. The highest biological yield was observed in Festuca rubra, next in Arrhenatherum elatius and Poa pratensis, and the smallest in Holcus lanatus and Agropyron repens. In F. rubra harvested yield held 13.8% of biological yield, and RSS biomass held 86.2%. In contrast, in H. lanatus harvested yield was 44.7% and RSS biomass was 55.3% of biological yield.

Dependence of anatomical structure features on morphological form of branching of grass shoots

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

The influence of partial covering with soil on the morphology and anatomy of regrowing stems of tufted grasses

Regeneration of the following tufted grasses was investigated: <i>Deschampsia caespitosa</i> (L.) P. B., <i>Holcus lanatus</i> L., <i>Lolium perenne</i> L., <i>L. multiflorum</i> Lam., <i>Arrhenatherum elatius</i> (L.) P. B., <i>Phleum pratense</i> L., <i> Bromus unioloides</i> H. B. K. and <i>Dactylis glomerata</i> L. The small clumps of these grasses consisting of four shoots has been covered with soil to the height of 12 cm. It was found that regrowth out of the buried tuft occurs by way of stems morphologically and anatomically resembling rhizomes. The buried parts of the regenerated stems were thinner and had sclerenchyma cylinder separated from the epidermis by a layer of parenchyma cells, whereas in the aerial parts sclerenchyma cylinder with islands of parenchyma was contiguous to epidermis. The tuft fragmentation has no harmful effect on regeneration and tillering of buried grasses probably due to the some leaves which has been left above the soil cover.

Species specific responses of common grassland plants to a generalist root herbivore (Agriotes spp. larvae)

Insect root herbivores can alter plant community structure by affecting the competitive ability of single plants. Our study aims at increasing knowledge on the impact of click beetle larvae (Elateridae, genus Agriotes) on grassland plant communities, by determining biomass responses as well as responses of the arbuscular mycorrhizal fungi (AMF) symbiosis to this widespread generalist root herbivore for eight common grassland plant species (Festuca rubra, Holcus lanatus, Poa pratensis, Achillea millefolium, Plantago lanceolata, Veronica arvensis, Medicago lupulina, Trifolium repens), belonging to three functional groups (grasses, herbs, legumes).The presence of larvae in the rhizosphere of individual plants had an overall negative effect on root biomass, which varied in degree between plant species, with more root biomass being removed from larger root systems. The effect of larvae on shoot biomass, total plant biomass and shoot/root ratio also differed in strength between plant species. Relative changes in root and total plant biomass ranged from a 71% and 55% loss, respectively, in V. arvensis to an 11% and 1% increase in T. repens, but were not related to root- or plant size. Root colonization by AMF and the length of extraradical AMF hyphae were not affected by larvae. The plant's functional group did not determine the response of the plant to feeding by larvae. Growth of larvae was positively correlated with root biomass, but did not depend on plant species or group identity.The results confirm the generalist nature of Agriotes spp. larvae, which depend on sufficient root quantity and are likely to feed most on those plant species whose roots are most abundant in their habitat. Their effect on the plant community may be generated through the ability of the respective plant species to cope with the herbivore damage, with tolerances being plant species rather than plant group specific.

Arsenic extractability and uptake by velvetgrass Holcus lanatus and ryegrass Lolium perenne in variously treated soils polluted by tailing spills

Phytostabilization should be considered as an appropriate phytoremediation technique to restore the area affected by tailing spills in Zloty Stok, where arsenic ores were mined and processed for several centuries. The study aimed to compare the suitability of velvetgrass (Holcus lanatus L.) and ryegrass (Lolium perenne L.) for development of plant cover in that area. Various treatments commonly applied to support phytostabilization were examined. A pot experiment was carried out to assess the effects of soil amendment with phosphate (P), sewage sludge (SS) and iron salts (Fe) on arsenic extractability and its uptake by grass. Four kinds of soil material, containing 356–5350mgkg−1 As, were examined. Velvetgrass proved to be more resistant than ryegrass to the toxicity of soil arsenic. Ammonium sulphate extractability of As in soils correlated well with As concentrations in the biomass of both grass species. In three of four tested soils, application of Fe failed to decrease As extractability and to reduce its concentrations in the aboveground parts of grasses. Application of P and SS resulted in increased As solubility in soils, but their effects on plant biomass and As uptake were ambiguous. SS had a strong beneficial influence on the growth of velvetgrass, while such an effect was not observed for ryegrass.

Changes in Sb speciation with waterlogging of shooting range soils and impacts on plant uptake

A pot experiment was conducted to investigate the solubility and redox species of antimony (Sb) in a relocated shooting range soil and its uptake by Lolium perenne L. and Holcus lanatus L. under different water regimes. After 1-week waterlogging, the total Sb concentration in soil solution decreased from ∼110 μg L−1 to <20 μg L−1, and slowly increased over the following 4 weeks, with the dissolution of Fe and Mn (hydr)oxides. In this process, half of the Sb in soil solution was reduced to Sb(III), which greatly affected the plant uptake of Sb. Waterlogging increased shoot Sb concentrations of L. perenne by ∼10 fold but decreased uptake in H. lanatus by 80%. Results indicate that Sb might primarily be taken up as Sb(III) by L. perenne and as Sb(V) by H. lanatus. Temporary waterlogging of soil may increase the risk of trace elements entering the food chain.

Axinotarsus pulicarius (F.) (Coleoptera: Melyridae: Malachiinae), a soft-winged flower beetle new to North America

Axinotarsus pulicarius (F.), a soft-winged flower beetle native to the Palearctic Region, is newly reported from North America. More than 100 specimens were swept from vegetation, mostly from flower heads of velvetgrass, Holcus lanatus L., in Delta (Tsawwassen), British Columbia, Canada, in 2010 and 2011. This is the first record of the genus and species in the New World.

The content of selenium in some species of meadow plants

The aim of the investigation carried out in 2006-2007 was to assess differences between 5 grass species and 5 species of plants belonging to meadow herbs in their ability to accumulate selenium. According to the results, among the grass species, the samples of Arrhenatherum elatuis L. had the highest average Se content (46 µg Se⋅kg -1 d.m.), and the lowest average Se amount was found in Holcus lanatus L. (24 µg Se⋅kg -1 d.m.). The content of Se in meadow weeds (70 µg Se⋅kg -1 d.m.) was approximately twice as high as in grasses (32 µg Se⋅kg-1 dm.). Among this group of plants, the highest Se accumulation occurred in Equisetum arvense L. (103 µg Se⋅kg-1 dm.) and the lowest – in Taraxacum officinale (59 µg Se⋅kg -1 dm.). Both in grasses and in meadow weeds, the Se content significantly depended on the amount of this element in soils. In the following species: Dactylis glomerata L., Arrhenatherum elatius L., Poa pratensis L. and Taraxacum officinale, the amount of accumulated Se was also conditioned by the soil’s abundance in organic and total C.

First Report of Grass Species (Poaceae) as Naturally Occurring Hosts of the Pine Pathogen Gibberella circinata.

Gibberella circinata (anamorph Fusarium circinatum) causes pitch canker in pines and is not known to have any hosts outside the Pinaceae. However, G. circinata is closely related to and interfertile with G. subglutinans, which is associated with grasses both as a pathogen and a commensal endophyte. Furthermore, studies under controlled conditions have shown that G. circinata can colonize corn (Zea mays) without inducing symptoms (4). To determine if G. circinata can also infect grasses under natural conditions, plants were collected in proximity to trees with symptoms of pitch canker in native stands of Pinus radiata (Monterey pine) on the Monterey Peninsula and P. muricata (bishop pine) at Pt. Reyes National Seashore on the California coast during July and August of 2011. Leaves and stems were rinsed in 0.1% Tween 20, immersed in 70% ethanol for 30 s followed by 1 min in 1% NaOCl, and placed on a Fusarium selective medium (FSM) (1). Single-spore subcultures of colonies growing from cultured plant material were transferred to 0.6% KCl agar and identified as G. circinata based on morphological criteria as described by Gordon et al. (2). G. circinata isolates were recovered from Holcus lanatus and Festuca arundinacea on the Monterey Peninsula and H. lanatus at Pt. Reyes National Seashore. Three isolates from each of these sources (nine total) and one known G. circinata isolate from pines (GL 17) were tested for virulence by inoculating 1-year-old, greenhouse-grown Monterey pine trees; three trees were inoculated, once for each isolate. Trees were inoculated by depositing 250 spores in a wound on the main stem by the method described by Gordon et al. (3). Two weeks later, all grass isolates had induced resinous branch cankers with lesions comparable in length (17 to 24 mm) and appearance to those caused by GL 17. Similar results were obtained when inoculations were repeated. One isolate from F. arundinacea and one from H. lanatus (collected at Pt. Reyes National Seashore) were tested and shown to be somatically compatible with tester strains for vegetative compatibility groups C6 and C1, respectively, both of which are associated with isolates previously recovered from diseased pines (2). GL 17 and one isolate each from F. arundinaceae and H. lanatus were tested for their ability to infect F. arundinaceae cv. Fawn. For each isolate, 20 14-day-old seedlings (10 pots with two plants per pot) were sprayed to runoff with an aqueous suspension of 106 spores per ml. All inoculations were repeated once. Two weeks after inoculation, leaves and stems were rinsed briefly in 0.1% Tween 20, immersed for 10 s in 70% ethanol, followed by 30 s in 1% NaOCl, and cultured on FSM. All tested isolates were recovered from at least some of the inoculated plants (range 20 to 100%), from living stems and leaves, as well as from senescing tissue. These results show that grass species can be symptomless hosts for G. circinata, constituting the first documentation of any host for this pathogen outside the Pinaceae. Studies are underway to further characterize the host range of G. circinata and assess the epidemiological implications of grasses as alternate hosts for the pitch canker pathogen.

Geographic origin and past climatic experience influence the response to late spring frost in four common grass species in central Europe

Late spring frost events can affect vegetation. The response of grassland species, however, is generally unknown. We explore the late‐frost sensitivity of four common European grass species and investigate whether these species exhibit local adaptations to late frost on a continental scale and whether past climatic experience influences late frost sensitivity.Ecotypes of Arrhenatherum elatius, Alopecurus pratensis, Festuca pratensis, and Holcus lanatus from Spain, Italy, Bulgaria, Hungary, Sweden and Germany were exposed to late frost after drought and warming manipulations in the preceding growing season in a common garden experiment.Late frost reduced the productivity of the grasses on average by 20%. Ecotypes differed in their late‐frost sensitivity in three of the four species and local adaptations to late frost were identified. Previous exposure to drought and warming caused differences in late‐frost sensitivity in some cases.The impact of late frost events may increase in a warmer world due to an earlier onset of growing and no change in timing of late frost events. The history of climatic exposure can alter the performance of plants, possibly through epigenetic mechanisms. Based on the complex response pattern observed, a maximization of genetic diversity is proposed as a promising adaptation strategy against climate change.

Aeroallergen Prick Skin Test and Autologous Serum Skin Test Results in Patients with Chronic Urticaria and Their Comparison

Dear Editor: The etiology of chronic urticaria (CU) cannot be identified in more than 75% of patients, even after an exhaustive search. The autologous serum skin test (ASST) based on the intradermal injection of autologous serum is a simple screening diagnostic procedure used in CU. Studies have shown that ASST is positive in almost half of patients with CIU1. Aeroallergen prick skin test (ASPT) can provide useful confirmatory evidence for immediate type I hypersensitivity2. The purpose of our study was to assess the prevalence of positivity of ASST and ASPT, and their relevance in patients with CU. Fifty CU patients (female/male: 35/15, mean age: 33.32±9.42 years) and 50 controls (female/male: 20/30, mean age: 36.84±13.13 years), who were classified according to age and gender, were included in the study. In all of the patients, physical urticaria, food and drug allergies, as well as urticarial vasculitis, were ruled out after taking a detailed history and performing relevant laboratory investigations. Clinical and laboratory details of all of the patients were recorded, using a standard format. The ASST and the ASPT were performed intradermally. The aeroallergen, used for ASPT, were Dermatophagoides farinae, D. pteronyssinus, betulecea (alder, birch, hazel, hornbeam), salicacea (poplar, willow), mixture of 4 cereals (barley, maize, oat, wheat), mixture of 5 grasses (cocksfoot, rye-grass timothy meadow grass, sweet vernal-grass), mixture of 12 grasses (cocksfoot, rye-grass timothy meadow grass, sweet vernal grass, oat grass, wild oat, meadow fescue, bent grass, yorkshire fog bermuda grass, bromus), compositae (golden rod, dandelion, cocklebur, ox-eye daisy), feathers mixture (duck, goose, hen), and cat. Data were analyzed by using SPSS 11.5 software (SPSS Inc., Chicago, IL, USA). Ki kare test was used for the statistical analytical approach, and t test was used for other variables. There was a significant difference between patients (27 patients, range: 34%) and controls (5 controls, range: 10%), according to ASST positivity (p 0.5). The most prevalent aeroallergens in the patients were D. farinae (16% of patients). Sixteen percent of the patients reacted to a mixture of 4 cereals, 12% reacted to a mixture of 5 grasses and 12% reacted to a mixture of 12 grasses. The difference, according to the controls, was not meaningful (p>0.05). ASST has been suggested as a screening test for CIU. In our study, based on the disease duration, there was no significant difference between the ASST positive and negative groups, similarly, the studies of Kultanan et al.2 and Nettis et al.3 Grattan et al.4 reported a 35% positive ASST result in patients with CU. Coban et al.5 found a positive ASST in 25 of 40 patients (62.5%) with CC. Our findings are similar to those reported in those studies. CIU can be provoked by a number of known and unknown factors and allergens. Some of these allergens can be identified by prick tests. In our study, the most positive reactions were seen with house dust mites. Caliskaner et al.6 prick tested 259 patients with CU with common aeroallergens. Seventy-one of the patients had positive reactions to one or more allergens. The most common allergens were house dust mites, followed by pollens, cockroaches and moulds. Tezcan et al.7 prick tested 5,055 patients, 556 of whom had CU. According to this study, 42% of patients reacted to house dust mites, 54% reacted to grass pollen and 45% reacted to cereal pollen. In our study, ASPT positivity was not high because the living area is not mouldy. In addition, both the number and species of plants and pollens are scarce. In our setting, ASST is the only available test for the diagnosis of autoimmune urticaria. It is a simple and inexpensive, semi-invasive and easy-to-perform test, which can be undertaken by a dermatologist to determine whether the patient's CIU is autoimmune in origin. As conventional approaches to management may be unsuccessful, ASST is especially important from the therapeutic point of view, as it can help the dermatologist to determine whether to initiate immunosuppressive therapy in CIU patients. When investigating the etiology of patients with CIU, the ASPT should be made with anamnesis.

Indirect effects of polycyclic aromatic hydrocarbon contamination on microbial communities in legume and grass rhizospheres

Background and aims Biodegradation of polycyclic aromatic hydrocarbons (PAHs) is accelerated in the presence of plants, due to the stimulation of rhizosphere microbes by plant exudates (nonspecific enhancement). However, plants may also recruit specific microbial groups in response to PAH stress (specific enhancement). In this study, plant effects on the development of rhizosphere microbial communities in heterogeneously contaminated soils were assessed for three grasses (ryegrass, red fescue and Yorkshire fog) and four legumes (white clover, chickpea, subterranean clover and red lentil).