The complete chloroplast genome of Agrostis capillaris L.

Agrostis capillaris is a cool-season turf grass species that is found worldwide in temperate countries, and a good Pb phytostabilizer. In this study, the entire chloroplast genome sequence of A. capillaris was determined by Illumina sequencing. The complete chloroplast genome was circular and composed of 136,396 bp nucleotides with a GC content of about 38.5%. There were a large single-copy region (LSC, 81,659bp), a small single-copy region (SSC, 12,593bp), and a pair of reverse repeat regions (IRs, 42,144bp) in the chloroplast genome. In total, the A. capillaris chloroplast genome contained 144 genes, including 96 protein-coding genes, 40 tRNA genes, and 8 rRNA genes. Phylogenetic analysis revealed that A. capillaris was closely related to A. gigantean. The sequence data of A. capillaris chloroplast genome could provide useful genetic information for the studies on phylogenetic and evolutionary of Agrostidinae.

Contrasted tolerance of Agrostis capillaris metallicolous and non-metallicolous ecotypes in the context of a mining technosol amended by biochar, compost and iron sulfate.

Metal(loid) contamination of soil, resulting from the mining activities, is a major issue worldwide, due to its negative effects on the environment and health. Therefore, these contaminated soils need to be remediated. One realistic method is the assisted phytostabilization, which aims at establishing a vegetation cover on the soil that will reduce metal(loid) bioavailability and spreading through the prevention of wind erosion and water leaching. In addition, amendments are applied to improve soil conditions and ameliorate plant growth. In this goal, biochar and compost showed good results in terms of amelioration of soil fertility and reduction in lead bioavailability. However, they usually have a negative effect on arsenic. On the contrary, iron sulfate showed capacity to reduce arsenic mobility through interaction with its iron hydroxides. Finally, the choice of the appropriate plant species is crucial for the success of assisted phytostabilization. One good option is to use endemic species, adapted to the metal(loid) stress, with a fast growth and large shoot and root systems. The aims of this study were to (1) evaluate the effects of applying biochar, compost and iron sulfate, alone or combined, to a former mine soil on the soil properties and Agrostis capillaris growth, and (2) assess the difference between two Agrostis capillaris ecotypes, an endemic metallicolous ecotype and a non-metallicolous ecotype. Results of the mesocosm experiment showed that amendment application improved soil properties, i.e., reduced soil acidity, increased nutrient availability and lower metal(loid) stress, the best being the combination biochar-compost-iron sulfate. These ameliorations allowed a better plant growth. Finally, the metallicolous ecotype performed better in terms of growth than the non-metallicolous one and could thus be used in an assisted phytostabilization process on the former mine site.

Effects of biochar, ochre and manure amendments associated with a metallicolous ecotype of Agrostis capillaris on As and Pb stabilization of a former mine technosol.

Metal(loid) soil pollution is a major environmental and health issue, requiring these areas to be remediated, for example through phytoremediation processes. In order to allow proper plant establishment and growth, amendments must be applied to highly contaminated and poorly fertile soils. Amendments are diverse, but many studies have shown the beneficial effects of biochar, manure and ochre, although studies on their combined use are scarce. Moreover, no studies have evaluated the effect of these combined amendments on endemic plant growth. Endemic plants growing on contaminated soils showed higher tolerance toward pollutants compared to plants coming from unpolluted areas. Therefore, the aim of the present study was to evaluate both the effect of amendments (single or combined) on the physicochemical properties of a former mining technosol, and the growth and metal(loid) accumulation ability of endemic Agrostis capillaris plants. This study revealed an improvement in the soil physicochemical properties following the application of amendments, with combined amendments showing better results than the application of just one. On top of this, Agrostis plants performed better on the amended technosols, especially the ones receiving manure, due to its high nutrient content. Finally, based on soil properties, plant growth and the metal(loid) accumulation profile, the use of biochar combined with manure seems to be the most appropriate treatment. Indeed, this treatment showed an improvement in both soil fertility and plant growth. Moreover, Agrostis plants grown in these conditions were among those showing higher root metal(loid) concentration associated with a lower translocation toward aerial parts.

A physiological approach to study the competition ability of the grassland species Trifolium pratense and Agrostis capillaris.

The response of plant species to external factors depends partly on the interaction with the environment and with the other species that coexist in the same ecosystem. Several studies have investigated the main traits that determine the competitive capacity of plant species, and although the relevance of the traits is not clear, traits both from belowground and aboveground have been observed. In this paper, we grew Trifolium pratense and Agrostis capillaris in intra- and interspecific competition, analyzing the photosynthetic metabolism and nitrogen uptake, among other variables. The results indicated that T. pratense possesses better competition ability due to the higher competitive performance for soil resources compared to A. capillaris, explained by a higher root biomass and a higher nitrogen uptake rate in the former than in the latter. These traits permitted T. pratense to show higher photosynthetic rate than A. capillaris when both species were grown in mixture. Furthermore, the interspecific competition provoked A. capillaris to activate its antioxidant metabolism, through SOD activity, to detoxify the reactive oxygen species generated due to its lower capacity for using the photochemical energy absorbed. In this experiment, we conclude that the competitiveness seems to be more related with soil resources competition than with light competition, and that the photosynthetic rate decline in A. capillaris is more a secondary effect as a consequence of nitrogen limitation.

Nanoscale Zero-Valent Iron Has Minimum Toxicological Risk on the Germination and Early Growth of Two Grass Species with Potential for Phytostabilization.

Two Poaceae species, Agrostis capillaris and Festuca rubra, were selected for their potential as phytostabilizing plants in multicontaminated soils. These species are resistant to contamination and maintain high concentrations of contaminants at the root level. Nanoscale zero-valent iron (nZVI) is an engineered nanomaterial with the ability to stabilize metal(loid)s in soils; its potential toxicological effects in the selected species were studied in a germination test using: (i) control variant without soil; (ii) soil contaminated with Pb and Zn; and (iii) contaminated soil amended with 1% nZVI, as well as in an hydroponic experiment with the addition of nZVI 0, 25, 50 and 100 mg L-1. nZVI had no negative effects on seed germination or seedling growth, but was associated with an increase in shoot growth and reduction of the elongation inhibition rate (root-dependent) of F. rubra seedlings. However, applications of nZVI in the hydroponic solution had no effects on F. rubra but A. capillaris developed longer roots and more biomass. Increasing nZVI concentrations in the growing solution increased Mg and Fe uptake and reduced the Fe translocation factor. Our results indicate that nZVI has few toxic effects on the studied species.

Data from experiments with tailing material and Agrostis capillaris at three scales: pot, lysimeter and field plot.

The data set consists in a file with two sheets: one includes a matrix of 297 rows and 46 columns, and the second one a matrix of 12 rows and 24 columns. In the first sheet each row is a replicate of an experimental variant with Agrostis capillaris growing on tailing substrate belonging to three experiments witch have the same variants, but are organized at three scales. The data from all experiments are in the same table, with a column indicating by a code the experiment to which they belong. In the second spreadsheet there is a table with the relative plant species cover in the experimental field plots. Experimental design and interpretation of the data are provided in "Implications of spatial heterogeneity of tailing material and time scale of vegetation growth processes for the design of phytostabilisation" [1].

Implications of spatial heterogeneity of tailing material and time scale of vegetation growth processes for the design of phytostabilisation.

Phytostabilisation projects for tailing dams depend on processes occurring at spatial scales of 106 m2 and at decadal time scales. Most experiments supporting the design and monitoring of such projects have much smaller spatial and time scales. Usually, they are only designed for one single scale. Here, we report the results of three coupled experiments performed at pot, lysimeter and field plot scales using six sampling periodstimes from 3 to 20 months. The work explicitly accounts for the sampling times when evaluating the effects of amendments on the performance of plants grown in tailing substrates. Two treatments with potentially complementary roles were applied: zeolites to decrease availability of Cd, Cu, Pb and Zn and green fertilizer to increase the availability of nutrients. Zeolites have a positive influence on plant development, especially in the early stages. Analyses of the pooled datasets for all sampling times revealed the possibility of predicting plant physiological variables, such as protein concentrations, pigments and oxidative stress enzyme activities, as a function of the factors extracted by principal component analysis from the metal concentrations in plants, phosphorus concentrations in plants, and sampling times. Two potentially general methodological rules were extracted: account for the spatial geochemical variability of tailings, and cover the broadest possible range of time scales by experiments. The proposed experimental methodology can be of general use for the design of tailing dam remediation technologies with improvements involving the set of measured variables and sampling frequency and by carefully relating the costs to the institutional aspects of tailing dam management.

The interaction between drought and elevated CO2 in water relations in two grassland species is species-specific.

Climate change can have major consequences for grassland communities since the different species of the community utilize different mechanisms for adaptation to drought and elevated CO2 levels. In addition, contradictory data exist when the combined effects of elevated CO2 and drought are analyzed because the soil water content is not usually similar between CO2 concentrations. Thus, the objectives of this work have been to examine the effect of water stress on plant water relations in two grassland species (Trifolium pratense and Agrostis capillaris), analyzing the possible differences between the two species when soil water content is equal in all treatments, and to elucidate if development under elevated CO2 increases drought tolerance and if so, which are the underlying mechanisms. At ambient CO2, when soil volumetric water content was 15%, both species decreased their water potential in order to continue taking up water. Trifolium pratense performed osmotic adjustment, while Agrostis capillaris decreased the rigidity of its cell wall; moreover, both species increased the root to shoot ratio and decreased leaf area. However, these mechanisms were not sufficient to maintain cell turgor. Elevated CO2 partially mitigated the negative impact of drought on turgor potential in Trifolium pratense through a higher osmotic adjustment and root to shoot ratio and in Agrostis capillaris through a higher leaf relative water content caused by higher hydraulic conductance, but the impact of drought was not mitigated in either species by higher soil water conservation.

Long-term changes of metal contents in two metallophyte species (Olkusz area of Zn-Pb ores, Poland).

The authors present the changes of the As, Cd, Fe, Mn, Pb and Zn contents in two plant-considered metallophytes: common bent Agrostis capillaris (blades) and birch Betula pendula (leaves and seeds), recorded in a Zn-Pb industrial region of Olkusz (Poland) in 1994 and 2014. The highest amounts of Cd (12 ppm) and Zn (2524 ppm) in the common bent occur in the vicinity of the mining and metallurgical works 'Boleslaw' in Bukowno. However, these values are significantly lower than those in 1994: Cd by 87 % and Zn by 52 %. The highest contents of Fe (2674 ppm), Mn (130 ppm) and Pb (334 ppm) in this grass species are in the vicinity of the closed Olkusz mine. These contents have increased in comparison with the 1994 figures: Fe by 56 %, Mn by 120 % and Pb by 6 %. In the birch leaves, the metal contents averaged for four sites are the following: As 2.1, Cd 6.5, Fe 261, Mn 110, Pb 70 and Zn 1657 ppm, being lower from the figures in 1994. The highest As, Fe and Pb contents of birch leaves occur in the habitat closest to the former Olkusz mine, while those of Cd, Mn and Zn in the habitat distant at 100 m from the active plant in Bukowno. The common bent grass generates better resistance mechanisms against the metals than does the birch. In the birch leaves, the contents of the metals are significantly lower than those of the grass blades, but higher from those of the birch seeds collected from the same tree individuals. It is a proof of good functioning of the mechanisms preventing excessive metal amounts from the cell metabolism and of the presence of physiological barriers protecting birch seeds as the generative organs.

Pb pollution in soils from a trap shooting range and the phytoremediation ability of Agrostis capillaris L.

Pb pollution caused by shooting sport activities is a serious environmental problem that has increased considerably in recent decades. The aims of this study were firstly to analyze Pb pollution in soils from a trap shooting range abandoned in 1999, secondly to study the effectiveness of different extractants [CaCl2, DTPA, NH4OAc, low molecular weight organic acids (LMWOA), and bidistilled water (BDW)] in order to determine Pb bioavailability in these soils, and finally to evaluate the phytoremediation ability of spontaneous vegetation (Agrostis capillaris L.). To this end, 13 soils from an old trap shooting range (Galicia, NW Spain) were studied. It was found that Pb levels in the soils were higher than 100 mg kg(-1), exceeding the generic reference levels, and three of these samples even exceeded the USEPA threshold level (400 mg kg(-1)). In general, the reagent that best represents Pb bioavailability and has the greatest extraction efficiency was CaCl2, followed by DTPA, NH4OAc, LMWOA, and BDW. A. capillaris Pb contents ranged between 9.82 and 1107.42 mg kg(-1) (root) and between 6.43 and 135.23 mg kg(-1) (shoot). Pb accumulation in roots, as well as the presence of secondary mineral phases of metallic Pb in the adjacent soil, showed the phytostabilization properties of A. capillaris.

The herbaceous landlord: integrating the effects of symbiont consortia within a single host.

Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC) by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.

Elevated CO2 enhances below-ground C allocation in three perennial grass species at different levels of N availability.

Three perennial grass species, Lolium perenne L., Agrottis capillaris L. and Festuca uvina L., were homogeneously labelled in phytotrons with 14 CO2 at two CO2 concentrations (350 and 700µl l-1 ). Plants were grown under two nitrogen regimes: one with a minor addition of 8 kg N ha-1 , the other with an addition of 278 kg N ha-1 . Carbon allocation over the different compartments of the plant/soil systems was measured: shoots, roots, rhizosphere soil (soil solution, microbial biomass and soil residue), and bulk soil. Elevated CO., increased total net 14 C recovery in all species by 14%, and significantly enhanced the below-ground 14 C allocation by 26%, this enhancement was 24%, 39% and 21 % for root, rhizosphere soil and bulk soil, respectively. Within the rhizosphere soil, the 14 C amounts in the soil solution (+ 69%) and soil residue (+ 49%,) increased significantly. Total microbial biomass-C in the rhizosphere soil was also increased (15 %) by the elevated CO2 treatment, but only in proportion to the increased root mass. No interactions were observed between the elevated CO2 , and N treatments. The N treatment increased total net 14 C recovery by more than 300% and 14 C was preferentially allocated to the shoots, leading to a significant increase in shoot-to-root ratio. However, N fertilization also increased (+111%) the absolute amount of 14 C in soil. The three species behaved differently, but no interactions were observed between CO2 treatment and plant species. These results show that elevated CO2 induces an increased C input into soil for all three grass species at both N levels. However, the highest absolute amounts were found in the soils of the fastest growing species and at the highest N level.

Effects of elevated CO2 , nitrogen form and concentration on growth and photosynthesis of a fast- and slow-growing grass.

Growth and photosynthesis of Agrostis capillaris L. and Nardus stricta L. were measured for plants grown under ambient and elevated concentrations of CO2 (340 and 550 µl CO2 l(-1) respectively) and a range of nitrogen concentrations (0.01, 0.1, 1 and 5 mg N l(-1) ) supplied as either ammonium sulphate or sodium nitrate. After 42 d of growth for A. capillaris and 49 d of growth for N. stricta, the higher nitrogen concentrations resulted in stimulation of growth. The form of nitrogen did not affect the total dry weight attained by A. capillaris. However, ammonium-grown N. stricta attained a greater total dry weight than did nitrate-grown plants. Nitrogen form influenced leaf area ratio, which was greater in nitrate-grown A. capillaris and in ammonium-grown N. stricta. At the two lowest nitrogen concentrations there was no effect of elevated CO2 on total dry weight in either species, whilst at the two highest nitrogen concentrations positive growth responses to elevated C02 were observed. Photosynthetic capacity and carboxylation efficiency were lower in plants grown in elevated CO2 at the two lowest nitrogen concentrations, and were associated with greater leaf soluble carbohydrate content and lower foliar nitrogen concentrations. By contrast, the CO2 treatment did not affect these parameters at the two highest nitrogen concentrations employed.

Nitrogen, phosphorus and potassium uptake and demand in Agrostis capillaris: the influence of elevated CO2 and nutrient supply.

Responses to elevated CO2 have been studied using Agrostis capillaris L., an upland grass which is abundant on nutrient-poor soils. Plants were grown in sand culture with a wide range of nitrogen, phosphorus and potassium concentrations, and the impact of CO2 on the demand for nutrients was determined using isotopic root bioassays. Plants grown with the smallest concentrations of N and P showed typical foliar symptoms associated with deficiency of these elements. However, even when supplies of N and P were limiting to growth, additional CO2 (250 ppm above ambient) influenced neither total N nor total P in above-ground tissues, nor nutrient demands as indicated by the bioassay. The estimates of the demand of the plants for K from the 86 Rb bioassay indicated an appreciable increase when plants were raised in elevated CO2 . For plants of the same size with the same nutrient supply, those grown in elevated CO2 consistently displayed an increased internal demand for K. Uptake of K was not however, enhanced by elevated CO2 even in non-limiting conditions and it might therefore be limited by a factor other than K supply. The overall conclusion from the experiments is that when A. capillaris is grown in elevated CO2 , uptake of N, P and K fails to increase proportionally with dry mass. This was true even when nutrient supplies were adequate, and it appears that nutrient-use-efficiency might increase to enable the plants to maintain growth in elevated CO2 .

The mechanisms of arsenate tolerance in Deschampsia cespitosa (L.) Beauv. and Agrostis capillaris L.: Adaptation of the arsenate uptake system.

Arsenate influx isotherms in Deschampsia cespitosa (L.) Beauv. and Agrostis capillaris L. showed that tolerance to arsenate in these grasses is achieved at least in part by adaptation of the arsenate uptake system, which leads to reduced influx of arsenate in arsenate-tolerant plants. In D. cespitosa, this reduction in arsenate ioflux was by suppression of the Vmax of the high-affinity uptake system and by an increase in the Km of the low-affinity uptake system. In A. capillaris the reduction in arsenate uptake in arsenate-tolerant plants was by a decrease in the Vmax of both uptake systems and by an increase in the Km of the high-affinity uptake system. The differences in the rates of arsenate influx between tolerant and non-tolerant plants was much greater for D. cespitosa than for A. capillaris. The mechanism of arsenate tolerance in D. cespitosa and A. capillaris was the same mechanism of tolerance that had been demonstrated in arsenate-tolerant Holcus lanatus L. Reduced arsenate influx by adaptation of the arsenate uptake mechanism is a mechanism of tolerance that has evolved in three separate species.

Adaptation of grasses in the Netherlands to air pollution.

In three separate experiments, the response of three populations of Agrostis capillaris L., Nardus stricta L., and Lolium perenne L., from areas differing in ambient air pollution concentrations, were examined in experimental fumigations using SO2 , O3 , NO2 and NH3 . Growth of A. capillaris generally increased following the fumigations, except at the highest pollutant concentrations (120 µg m-3 O3 , alone or combined with 150 µg m-3 SO2 and 35 µg m-3 NO2 ). Growth of each population of N. stricta was stimulated by the SO2 and NH3 combination, but was significantly increased only in the populations originating from the most heavily polluted of the three areas. The growth of L. perenne was not inhibited by any air pollutant or combination of pollutants. Despite a low growth rate in clean air and a large amount of within-population variation, biomass production was significantly stimulated by the highest pollutant mixture. The response of each species to the experimental treatments depended in part on the location from which it originated. This site-dependent (population) response differed between species, suggesting that the selective processes induced by these air pollutant concentrations were insufficient for a clear-cut adaptation to gaseous air pollutants.

THE PERFORMANCE OF AGROSTIS CAPILLARIS L. GENOTYPES, DIFFERING IN COPPER TOLERANCE, IN RYEGRASS SWARDS ON NORMAL SOIL.

Sample sub-populations, each of six plants, were chosen for high, mid and low tolerance of copper from each of two naturally-occurring copper tolerant populations and from tolerant individuals selected from a cultivar of Agrostis capillaris L. The naturally-occurring ecotypes came from a closed sward community at Drws y Coed, and from an open community at Parys Mountain, both copper mines in North Wales. Clonal replicates of all plants were introduced into swards of perennial ryegrass cvs. S23 or S24, growing on normal soil at the University of Liverpool Botanic Gardens. S23 plots were cut eight times between June 1977 and July 1978, whilst S24 plots were cut 3 times during the same period. Half the experimental plots received N, P, K, fertilizer; the rest received none. Plants selected from the cultivar (selected) produced most dry matter, and with infrequent defoliation flowered freely in competition with ryegrass. Those taken from Parys Mountain mine spoil produced least dry matter and no inflorescences. Drws y Coed plants were intermediate in dry matter and inflorescence production. These results may reflect differences in population density in the habitats from which the populations were sampled. Sub-populations chosen for high, mid or low copper tolerance within the selected and Drws y Coed populations did not differ significantly in dry matter yield. By contrast under certain circumstances Parys Mountain plants with low tolerance outyielded other more tolerant plants. These results are considered with respect to growth strategies adopted by plants growing on and off copper mine sites.