The molecular regulatory mechanism of reed canary grass under salt, waterlogging, and combined stress was analyzed by transcriptomic analysis.

BACKGROUND: Reed canary grass has been identified as a suitable species for restoring plateau wetlands and understanding plant adaptation mechanisms in wetland environments. In this study, we subjected a reed canary grass cultivar 'Chuanxi' to waterlogging, salt, and combined stresses to investigate its phenotypic characteristics, physiological indices, and transcriptome changes under these conditions. RESULTS: The results revealed that the growth rate was slower under salt stress than under waterlogging stress. The chlorophyll content and energy capture efficiency of the PS II reaction center decreased with prolonged exposure to each stress. Conversely, while the activities of enzymes associated with respiratory metabolism, as well as MDA, PRO, Na+, and K+-ATPase, increased. The formation of distinct aerenchyma was observed under waterlogging stress and combined stress. Transcriptome sequencing analysis identified 5,379, 4,169, and 14,993 DEGs under CK vs. W, CK vs. S, and CK vs. SW conditions, respectively. The WRKY was found to be the most abundant under waterlogging stress, whereas the MYB predominated under salt stress and combined stress. Glutathione metabolic pathways and Plant hormone signal transduction have also been found to play important roles in stress. CONCLUSION: By integrating phenotypic, physiological, anatomical, and transcriptomic, this research provides valuable insights into how reed canary grass responds to salt, waterlogging, and combined stresses. These findings may inform the ecological application of reed canary grass in high-altitude wetlands and for breeding purposes.

Immobilisation of arsenic in contaminated soil by electrokinetics in an outdoor experiment.

Although landfilling is environmentally and economically unsustainable, it is the dominant soil remediation method in EU member states. This paper describes part of a study on mixed contaminants that investigated the stabilisation of arsenic (As) in contaminated soil in an outdoor box experiment with electrokinetic treatment (EK). The experiment was conducted in two 1 m3 boxes, each containing a 20 cm bottom layer of sand, overlaid with 20 cm of peat. In EK, a pulsating, low-voltage current was applied with the intention of corroding the zerovalent iron (Fe) electrodes, migrating ionic Fe species, and forming secondary iron minerals, thereby immobilizing As. Porewater samples were collected over two seasons to determine whether the treatment decreased the concentration of dissolved As. Sequential extraction was performed on the soil samples to determine whether the fraction of Fe-bound As increased. Reed canary grass was planted in one of the boxes during the second season and analysed for As uptake. The results showed that the treatment decreased the porewater As concentration in sand by 50-54 %, while the concentration of Fe increased. The sequential extraction of sand showed that the fraction of As bound to poorly crystalline Fe oxides increased during this time. This treatment effect was less visible in the peat. Moreover, the exchangeable As fraction increased in both peat and sand, most likely because of the decrease in redox potential at the end of the experiment. The plants grown in treated soil accumulated less As than those grown in untreated soil, indicating that the phytoavailable As fraction decreased. This study showed that EK remediation can be a suitable in situ remediation technique, mostly in sand. Future research should focus on redox control to further optimise EK remediation and ensure long-term As stability in treated soils.

A circular economy approach to drinking water treatment residue management in a catchment impacted by historic metal mines.

Drinking water treatment residues (DWTR) from mining areas which remove and contain potentially toxic elements (PTE) could still potentially be used as a soil amendment to restore contaminated sites in the same catchment, thus eliminating waste and reducing the chemical and physical mobility of the pollutants. To assess this restorative and regenerative approach to DWTR management, field and pot trials were established with soils from a historic Pb-Zn mine site in the North East of England, amended with either local DWTR or the nearest available municipal green waste compost (GWC). Soils from the mine site were found to have very low levels of nutrients and very high levels of PTE (Pb and Zn > 13, 000 mg/kg). The perennial grass species Phalaris arundinacea, known for many ecosystem service benefits including soil stabilization, was used throughout this study. The application of the BCR sequential extraction to soils amended with the DWTR in the pot trials found a significant decrease in the bioavailability of Pb and Cu (p < 0.05) after plant growth when compared with an unamended control. The field trial involved 648 pre-grown grass plants planted-out into mine soils amended with either DWTR, GWC or a mixture (MIX) of the two, all at rates of 25-30% w/w. Both amendments and the MIX had significant positive effects on biomass production compared to the unamended control in the following order GWC > MIX > DWTR (p < 0.05). Results of the elemental analysis of biomass from the field trial were generally ambiguous and did not reflect the decreased bioavailability noted in the pot trials using the BCR procedure. Pot trials, however, showed increases in plant growth and decreases in concentrations of Cr, Cu, Pb and Zn in above ground biomass following the application of both amendments. Further work should involve the testing of a mixture of DWTR and other soil amendments to enhance plant growth. The success of these trials should provide confidence for those working in drinking water treatment and catchment management to reuse the waste residues in a circular economy and a sustainable way that could improve water quality over time.

A Robust Process to Produce Lignocellulosic Nanofibers from Corn Stover, Reed Canary Grass, and Industrial Hemp.

The use of agricultural waste biomass for nanocellulose production has gained interest due to its environmental and economic benefits compared to conventional bleached pulp feedstock. However, there is still a need to establish robust process technologies that can accommodate the variability of waste feedstocks and to understand the effects of feedstock characteristics on the final nanofiber properties. Here, lignocellulosic nanofibers with unique properties are produced from various waste biomass based on a simple and low-cost process using mild operating conditions. The process robustness is demonstrated by diversifying the feedstock, ranging from food crop waste (corn stover) to invasive grass species (reed canary grass) and industrial lignocellulosic residues (industrial hemp). This comprehensive study provides a thorough examination of the influence of the feedstocks' physico-chemical characteristics on the conversion treatment, including process yield, degree of delignification, effectiveness of nanofibrillation, fiber morphology, surface charge, and density. Results show that nanofibers have been successfully produced from all feedstocks, with minor to no adjustments to process conditions. This work provides a framework for future studies to engineer nanocellulose with specific properties by taking advantage of biomass feedstocks' intrinsic characteristics to enable versatile applications.

Recovery of microelements from municipal sewage sludge by reed canary grass and giant miscanthus.

The aim of the study was to evaluate the content, uptake, and utilization of Al, Mn, Fe, Co, and Mo from municipal sewage sludge by the reed canary grass (RCG) and the giant miscanthus (MG). The impact of sewage sludge on the mass ratios between microelements contained in the plant biomass was analyzed as well. The long-term field experiment consisted in application of four levels of fertilization with sewage sludge: 10, 20, 40, and 60 Mg DM·ha-1. A non-fertilized control object (0 Mg DM·ha-1) was used as well. The miscanthus biomass was characterized by higher content of Al and Mn, whereas higher levels of Fe, Co, and Mo were determined in the reed canary grass biomass. As in the case of the element content, the giant miscanthus was characterized by highest level of Al and Mn uptake, while the highest uptake of Fe, Co, and Mo was exhibited by the reed canary grass. In the group of the analyzed microelements, the giant miscanthus showed the highest the recovery of Mo (47%) followed by Mn (39%), Fe (35%), and Co (15%), and the lowest uptake was determined in the case of Al (5%).

In addition to the use of their biomass for the production of renewable energy, energy crops (reed canary grass, giant miscanthus) can be used to recover microelements from municipal sewage sludge. Energy crop biomass can therefore be a potential source of microelements in animal feed. Attention was paid to the mass ratios of Fe:Mn, Fe:Al, Fe:Co, Fe:Mo, Mn:Al, Mn:Co, Mn:Mo, and Co:Mo in the biomass yield of the species used.

Report of two distinct ribotypes in ITS sequences of Phalarisarundinacea (Poaceae) in western Canada and Alaska.

Background: Phalarisarundinacea L. (reed canary grass) is a widely occurring grass throughout the Northern Hemisphere. In North America, it is thought to consist of introduced agricultural forms from Europe as well as native populations. New information: During a survey of Phalarisarundinacea in western Canada, we discovered two distinct ribotypes in the sequences of the internal transcribed spacer (ITS) of the nuclear ribosomal DNA: one full length (ITS-long) and one with a seven base pair deletion (ITS-short). In addition, ITS-long plants have fixed heterozygosity indicating possible polyploidy. Phylogenetic analysis reveals that ITS-short is a unique ribotype that characterises an intraspecific clade. We designed an efficient PCR-based assay that allows sizing of a 238/245 base pair fragment in a capillary sequencer. This approach provides a novel marker that could be useful in future surveys of Phalarisarundinacea.

Effects of inoculants on the fermentation characteristics and in vitro digestibility of reed canary grass (Phalaris arundinacea L.) silage on the Qinghai-Tibetan Plateau.

To effectively use local available grass resources to cover the winter feed shortage on the Qinghai-Tibetan Plateau, direct-cut and wilted reed canary grass (RCG) silages were prepared by using a rolled-bale system, and their ensiling characteristics and in vitro digestibility were studied. Silages were treated without (control) or with inoculants including LP (Lactobacillus plantarum), LPLB (L. plantarum, L. buchneri), and LPLBc (L. plantarum, L. buchneri, and cellulase), and were stored at ambient temperature (5.7-14.6°C) for 90 days. Compared with control, the inoculated silages increased (p < .05) lactic acid and acetic acid contents, and reduced (p < .05) final pH value and ammonia-N ratio of total N. The highest WSC content (41.2 g/kg DM) occurred for LPLB-inoculated silage, whereas LPLBc-treated silage displayed the lowest contents of NDF (522.9 g/kg DM) and ADF (275.5 g/kg DM). In addition, LPLBc-inoculated silage had the highest in vitro gas production (51.0 ml/g DM), in vitro DM digestibility (619.3 g/kg DM), and metabolic energy (9.6 kJ/kg DM). These results confirmed that treatments with inoculants at ensiling could improve silage fermentation and in vitro digestibility of RCG, and this could be a potential winter feed for animals on the Qinghai-Tibetan Plateau.

Transcriptome characterization and differentially expressed genes under flooding and drought stress in the biomass grasses Phalaris arundinacea and Dactylis glomerata.

BACKGROUND AND AIMS: Perennial grasses are a global resource as forage, and for alternative uses in bioenergy and as raw materials for the processing industry. Marginal lands can be valuable for perennial biomass grass production, if perennial biomass grasses can cope with adverse abiotic environmental stresses such as drought and waterlogging. METHODS: In this study, two perennial grass species, reed canary grass (Phalaris arundinacea) and cocksfoot (Dactylis glomerata) were subjected to drought and waterlogging stress to study their responses for insights to improving environmental stress tolerance. Physiological responses were recorded, reference transcriptomes established and differential gene expression investigated between control and stress conditions. We applied a robust non-parametric method, RoDEO, based on rank ordering of transcripts to investigate differential gene expression. Furthermore, we extended and validated vRoDEO for comparing samples with varying sequencing depths. KEY RESULTS: This allowed us to identify expressed genes under drought and waterlogging whilst using only a limited number of RNA sequencing experiments. Validating the methodology, several differentially expressed candidate genes involved in the stage 3 step-wise scheme in detoxification and degradation of xenobiotics were recovered, while several novel stress-related genes classified as of unknown function were discovered. CONCLUSIONS: Reed canary grass is a species coping particularly well with flooding conditions, but this study adds novel information on how its transcriptome reacts under drought stress. We built extensive transcriptomes for the two investigated C3 species cocksfoot and reed canary grass under both extremes of water stress to provide a clear comparison amongst the two species to broaden our horizon for comparative studies, but further confirmation of the data would be ideal to obtain a more detailed picture.

Land use of drained peatlands: Greenhouse gas fluxes, plant production, and economics.

Drained peatlands are hotspots for greenhouse gas (GHG) emissions, which could be mitigated by rewetting and land use change. We performed an ecological/economic analysis of rewetting drained fertile peatlands in a hemiboreal climate using different land use strategies over 80 years. Vegetation, soil processes, and total GHG emissions were modeled using the CoupModel for four scenarios: (1) business as usual-Norway spruce with average soil water table of -40 cm; (2) willow with groundwater at -20 cm; (3) reed canary grass with groundwater at -10 cm; and (4) a fully rewetted peatland. The predictions were based on previous model calibrations with several high-resolution datasets consisting of water, heat, carbon, and nitrogen cycling. Spruce growth was calibrated by tree-ring data that extended the time period covered. The GHG balance of four scenarios, including vegetation and soil, were 4.7, 7.1, 9.1, and 6.2 Mg CO2 eq ha-1  year-1 , respectively. The total soil emissions (including litter and peat respiration CO2 + N2 O + CH4 ) were 33.1, 19.3, 15.3, and 11.0 Mg CO2 eq ha-1  year-1 , respectively, of which the peat loss contributed 35%, 24%, and 7% of the soil emissions for the three drained scenarios, respectively. No peat was lost for the wet peatland. It was also found that draining increases vegetation growth, but not as drastically as peat respiration does. The cost-benefit analysis (CBA) is sensitive to time frame, discount rate, and carbon price. Our results indicate that the net benefit was greater with a somewhat higher soil water table and when the peatland was vegetated with willow and reed canary grass (Scenarios 2 and 3). We conclude that saving peat and avoiding methane release using fairly wet conditions can significantly reduce GHG emissions, and that this strategy should be considered for land use planning and policy-making.

Photo-protective mechanisms in reed canary grass to alleviate photo-inhibition of PSII on the Qinghai-Tibet Plateau.

Due to its characteristic of high biomass yield potential, there is considerable interest in cultivating Phalaris arundinacea L. cv. 'chuancaoyin No.3' (reed canary grass) on the Qinghai-Tibet Plateau where there is an abundance of alpine steppe meadow and a potential large market for animal husbandry. In this study, we 1) investigate whether reed canary grass exhibits superior productive capacity to Elymus nutans 'Aba' (E. nutans), ordinary common pasture, during the long warm days of summer at high-altitude; and 2) compare the cold tolerance between reed canary grass and E. nutans, including photosynthesis, photo-inhibition, and photo-protection. The results suggest that reed canary grass exhibits higher photosynthetic capacity compared to E. nutans at latitudes of the cool temperate zone. Meanwhile, cold-induced photo-inhibition and photo-damage at high altitudes in reed canary grass were due to both stomatal and non-stomatal limitation, and the enhancement in photo-respiration, thermal dissipation, and Mehler reaction are important processes to minimize the negative effects of high elevation and a cold environment.

Water use efficiency and shoot biomass production under water limitation is negatively correlated to the discrimination against 13C in the C3 grasses Dactylis glomerata, Festuca arundinacea and Phalaris arundinacea.

Climate change impacts rainfall patterns which may lead to drought stress in rain-fed agricultural systems. Crops with higher drought tolerance are required on marginal land with low precipitation or on soils with low water retention used for biomass production. It is essential to obtain plant breeding tools, which can identify genotypes with improved drought tolerance and water use efficiency (WUE). In C3 plant species, the variation in discrimination against 13C (Δ13C) during photosynthesis has been shown to be a potential indicator for WUE, where discrimination against 13C and WUE were negatively correlated. The aim of this study was to determine the variation in the discrimination against 13C between species and cultivars of three perennial C3 grasses (Dactylis glomerata (cocksfoot), Festuca arundinacea (tall fescue) and Phalaris arundinacea (reed canary grass)) and test the relationships between discrimination against 13C, season-long water use WUEB, shoot and root biomass production in plants grown under well-watered and water-limited conditions. The grasses were grown in the greenhouse and exposed to two irrigation regimes, which corresponded to 25% and 60% water holding capacity, respectively. We found negative relationships between discrimination against 13C and WUEB and between discrimination against 13C and shoot biomass production, under both the well-watered and water-limited growth conditions (p < 0.001). Discrimination against 13C decreased in response to water limitation (p < 0.001). We found interspecific differences in the discrimination against 13C, WUEB, and shoot biomass production, where the cocksfoot cultivars showed lowest and the reed canary grass cultivars highest values of discrimination against 13C. Cocksfoot cultivars also showed highest WUEB, shoot biomass production and potential tolerance to water limitation. We conclude that discrimination against 13C appears to be a useful indicator, when selecting C3 grass crops for biomass production under drought conditions.

The alkaloid gramine in the anaerobic digestion process-inhibition and adaptation of the methanogenic community.

As many plant secondary metabolites have antimicrobial activity, microorganisms of the anaerobic digestion process might be affected when plant material rich in these compounds is digested. Hitherto, the effects of plant secondary metabolites on the anaerobic digestion process are poorly investigated. In this study, the alkaloid gramine, a constituent of reed canary grass, was added daily to a continuous co-digestion of grass silage and cow manure. A transient decrease of the methane yield by 17 % and a subsequent recovery was observed, but no effect on other process parameters. When gramine was infrequently spiked in higher amounts, the observed inhibitory effect was even more pronounced including a 53 % decrease of the methane yield and an increase of acetic acid concentrations up to 96 mM. However, the process recovered and the process parameters were finally at initial values (methane yield around 255 LN CH4 per gram volatile solids of substrate and acetic acid concentration lower than 2 mM). The bacterial communities of the reactors remained stable upon gramine addition. In contrast, the methanogenic community changed from a well-balanced mixture of five phylotypes towards a strong dominance of Methanosarcina (more than two thirds of the methanogenic community) while Methanosaeta disappeared. Batch inhibition assays revealed that acetic acid was only converted to methane via acetoclastic methanogenesis which was more strongly affected by gramine than hydrogenotrophic methanogenesis and acetogenesis. Hence, when acetoclastic methanogenesis is the dominant pathway, a shift of the methanogenic community is necessary to digest gramine-rich plant material.

Variation in sequences containing microsatellite motifs in the perennial biomass and forage grass, Phalaris arundinacea (Poaceae).

Forty three microsatellite markers were developed for further genetic characterisation of a forage and biomass grass crop, for which genomic resources are currently scarce. The microsatellite markers were developed from a normalized EST-SSR library. All of the 43 markers gave a clear banding pattern on 3% Metaphor agarose gels. Eight selected SSR markers were tested in detail for polymorphism across eleven DNA samples of large geographic distribution across Europe. The new set of 43 SSR markers will help future research to characterise the genetic structure and diversity of Phalaris arundinacea, with a potential to further understand its invasive character in North American wetlands, as well as aid in breeding work for desired biomass and forage traits. P. arundinacea is particularly valued in the northern latitude as a crop with high biomass potential, even more so on marginal lands.

The use of reed canary grass and giant miscanthus in the phytoremediation of municipal sewage sludge.

The application of municipal sewage sludge on energy crops is an alternative form of recycling nutrients, food materials, and organic matter from waste. Municipal sewage sludge constitutes a potential source of heavy metals in soil, which can be partially removed by the cultivation of energy crops. The aim of the research was to assess the effect of municipal sewage sludge on the uptake of heavy metals by monocotyledonous energy crops. Sewage sludge was applied at doses of 0, 10, 20, 40, and 60 Mg DM · ha(-1) once, before the sowing of plants. In a 6-year field experiment, the effect of four levels of fertilisation with sewage sludge on the uptake of heavy metals by two species of energy crops, reed canary grass (Phalaris arundinacea L.) of 'Bamse' cultivar and giant miscanthus (Miscanthus × giganteus GREEF et DEU), was analysed. It was established that the increasing doses of sewage sludge had a considerable effect on the increase in biomass yield from the tested plants. Due to the increasing doses of sewage sludge, a significant increase in heavy metals content in the energy crops was recorded. The heavy metal uptake with the miscanthus yield was the highest at a dose of 20 Mg DM · ha(-1), and at a dose of 40 Mg DM · ha(-1) in the case of reed canary grass. Research results indicate that on account of higher yields, higher bioaccumulation, and higher heavy metal uptake, miscanthus can be selected for the remediation of sewage sludge.

Accumulation and distribution of macroelements in the organs of Phalaris arundinacea L.: Implication for phytoremediation.

The aim of this study was to assess nutrient and alkali metal accumulation and their distribution in the organs of Phalaris arundinacea and relations between environmental macroelement concentrations and accumulation in plant tissues. The content of N, P, K, Ca, Mg and Na in water, bottom sediments and different organs of Phalaris arundinacea from the Bystrzyca River (Lower Silesia) was determined. The organs of the reed canary grass contained relatively high amounts of macroelements and differed significantly in their accumulation. All macroelements other than Na were accumulated in the highest amounts in aboveground, photosynthetic tissues. Phalaris arundinacea is an Na and Ca excluder plant and an N, P, Mg and K accumulator. Transport efficiency from bottom sediments to plant roots was higher than between plant organs. Nitrogen, P and K are taken up actively while Ca passively. The high translocation ratio of nutrients, particularly for Ca, Mg, K and N, makes the reed canary grass suitable for nutrient phytoextraction from water and bottom sediments of eutrophic lakes and rivers. Bottom sediments can be considered the primary source of Ca for Phalaris arundinacea.

Comparison of biogas production from wild and cultivated varieties of reed canary grass.

The chemical composition and efficiency of biogas production in the methane fermentation process of silages of wild and cultivated varieties of reed canary grass were compared. An attempt was made to answer the question on how the habitat and the way of utilization of plants affect chemical composition and biogas yield. Physicochemical properties such as dry matter, organic dry matter, protein, fat, crude fiber fraction, macro- and microelements content were considered. The anaerobic digestion process and FTIR analysis were also carried out. The results showed that the two varieties differ essentially in their physical and chemical properties. The cultivated variety was characterized by higher biogas yield (406Ndm(3)kg(-1) VS) than the wild one (120Ndm(3)kg(-1) VS). This was probably related to the chemical composition of plants, especially the high content of indigestible crude fiber fractions and ash. These components could reduce biogas quantity and quality.

Comparing the genetic architecture and potential response to selection of invasive and native populations of reed canary grass.

Evolutionary processes such as migration, genetic drift, and natural selection are thought to play a prominent role in species invasions into novel environments. However, few empirical studies have explored the mechanistic basis of invasion in an evolutionary framework. One promising tool for inferring evolutionarily important changes in introduced populations is the genetic variance-covariance matrix (G matrix). G matrix comparisons allow for the inference of changes in the genetic architecture of introduced populations relative to their native counterparts that may facilitate invasion. Here, we compare the G matrices of reed canary grass (Phalaris arundinacea L.) populations across native and invasive ranges, and between populations along a latitudinal gradient within each range. We find that the major differences in genetic architecture occur between populations at the Northern and Southern margins within each range, not between native and invasive populations. Previous studies have found that multiple introductions in introduced populations caused an increase in genetic variance on which selection could act. In addition, we find that differences in the evolutionary potential of Phalaris populations are driven by differences in latitude, suggesting that selection also shapes the evolutionary trajectory of invasive populations.