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α-Ketoglutarate (AKG) is a key intermediate metabolite in the tricarboxylic acid cycle of respiration and a precursor for glutamate, playing important roles in regulating plant growth and stress tolerance. The objectives of this study were to examine effects of AKG on heat tolerance characterized by leaf senescence in a cool-season grass species by foliar application and to determine major metabolites and associated metabolic pathways regulated by AKG for its effects on heat tolerance. Perennial ryegrass (Lolium perenne L.) plants were exposed to heat stress (35/30 °C, day/night) or optimal temperature (25/20 °C, day/night, non-stress control) in controlled-environment growth chambers. The solution containing AKG (5 mM) was applied to leaves by spraying 7 d prior to the initiation of heat stress and every 7 d during the heat stress period. Exogenous application of AKG enhanced heat tolerance in perennial ryegrass, as manifested by significant increases in leaf chlorophyll content, photochemical efficiency, and membrane stability, as well as activities of antioxidant enzymes for H 2 O 2 scavenging in AKG-treated plants relative to untreated control plants exposed to heat stress. Metabolic profiling and pathway analysis demonstrated that exogenous AKG application enhanced metabolite accumulation in four major metabolic pathways, including antioxidant metabolism, amino acid metabolism, glycolysis and tricarboxylic acid cycle of respiration, and pyrimidine metabolism, contributing to AKG-improved heat tolerance in perennial ryegrass. • α-Ketoglutarate (AKG) enhanced heat tolerance in perennial ryegrass. • AKG suppressed heat-induced leaf senescence. • AKG regulated the metabolism of antioxidant, amino acids, pyrimidine, glycolysis, and TCA cycle of respiration. [ABSTRACT FROM AUTHOR]

Protein extracts from green leaves, consisting of mainly RuBisCO, have potential applications for human consumption. However, their properties are highly influenced by the extraction process applied. This work assessed the impact of the extraction method on the solubility profile and emulsifying properties of two protein concentrates from perennial ryegrass, obtained using two different approaches. These two methods differed in the application (or absence) of a heating step (50 °C for 30 min) to improve the removal of chloroplast material. The functionality of both protein concentrates was highly influenced by the isoelectric point of the proteins. The extract containing less residual chloroplast material showed greater solubility, up to 40 % more, and superior emulsifying capacity and stability, at non-acidic pH, similar to WPI. At pH above 6, the protein extract which contained residual chloroplast material was significantly less soluble, which limited its performance as emulsifier. Therefore, the extraction process critically impacted the final product's functionality. This work demonstrated that effectively removing chloroplast material is essential to achieve targeted techno-functional properties of an ingredient and the food product in which it is used. [Display omitted] • Protein concentrates from perennial ryegrass were explored as food emulsifiers. • Extraction method impacted the functional properties of the proteins. • Heating step during protein extraction improved emulsification properties. • Interfacial properties of both concentrates were highly influenced by the pH. • Balance between extraction yield and functional properties should be considered. [ABSTRACT FROM AUTHOR]

Plantain (Plantago lanceolata) is an herb used to reduce the forage deficit of ryegrass-based pastures during the summer. This herb is being promoted for its reduced environmental impact in terms of nitrogen emissions, particularly reducing urinary nitrogen. However, the effect of plantain on emissions of enteric CH 4 , the main greenhouse gas produced from ruminant-based production systems, is not known. The aim of the present trial was to determine CH 4 emissions and rumen fermentation characteristics of nonlactating dairy cows fed 100% plantain (PLT) or 100% perennial ryegrass (RG; Lolium perenne) in 2 experiments (E1 and E2). The forages were in a vegetative growth stage in E1 and were in a reproductive growth stage in E2. Methane emissions from 16 cows in each experiment were measured in respiration chambers for 2 d. Methane emissions per unit of dry matter intake (CH 4 yield) were 15 and 28% less for cows fed PLT than those fed RG in E1 and E2, respectively. Dry matter digestibility of PLT was 7 and 27% less than that of RG in E1 and E2, respectively, and CH 4 per unit of dry matter digested was similar for PLT and RG in both experiments. There were only minor (but some significant) differences in rumen fermentation characteristics between cows fed PLT and RG in both experiments. In conclusion, CH 4 yield was lower for cows fed PLT compared with those fed RG in both experiments and this reduction was largely explained by the lesser dry matter digestibility of PLT. [Display omitted] [ABSTRACT FROM AUTHOR]

Epichloë endophytes in grass associations express a myriad of secondary metabolites which can affect the health of grazing animals and reduce the impact of insect pests on pasture. The ideal endophyte-grass association must have a favourable chemical profile such that the impact on animal health is minimised while the beneficial, deterrent effect on insect pests is maximised. A number of endophyte-perennial ryegrass associations have been successfully commercialised but research is on-going to further improve production in farming systems. Secondary metabolites expressed by endophyte-infected tall fescue include lolines, an animal-safe class of compound which imparts a potent effect on insects. Since endophyte-infected perennial ryegrass does not express lolines, a tall fescue endophyte, AR501, was inoculated into perennial ryegrass in an attempt to improve the insect resistance of this pasture type. In addition to animal safety, it is imperative that consideration is given to the safety of humans consuming animal products derived from livestock grazing the novel pasture. Although pure loline alkaloids have previously been tested on mice it is essential that the entire AR501 endophyte-infected perennial ryegrass matrix is tested since this will result in the exposure of both known and unknown secondary metabolites to mice. Three treatment groups each containing 6 male and 6 female mice were fed diets containing AR501 endophyte-infected perennial ryegrass seed (30%), perennial ryegrass seed containing no endophyte (30%) or a diet without seed (control) for 3 weeks. Mice fed control diet ate more than either of the treatment groups fed a diet containing seed. Male mice fed diet containing Nil endophyte seed ate more than those eating AR501 endophyte-infected perennial ryegrass seed although there was no difference observed in the food intake of female mice. While a few statistically significant differences were observed in the haematology and serum biochemical data, in every instance the difference was restricted to only one gender so is considered unlikely to be of toxicological significance. Mice fed AR501 endophyte-infected perennial ryegrass seed remained healthy throughout the experimental period despite consuming 62,000 mg/kg lolines and 4600 mg/kg peramine per day as well as the wide array of other unknown secondary metabolites expressed by this endophyte. Although animal products may contain additional metabolites as a result of animal metabolism, this experiment raises no food safety concerns for AR501 endophyte-infected perennial ryegrass. [Display omitted] • Endophytes are used to confer beneficial insect pest protection to their host plants. • Endophytes produce a myriad of known and unknown secondary metabolites. • Secondary metabolites consumed by animals could go up the food chain to be consumed by humans. • AR501 endophyte-infected ryegrass seed was fed to mice for 21 days. • The lack of toxicity observed raises no food safety concerns for these compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • Across experiments NUtE ranged between 19 and 70 kg DM kg−1 N uptake. • The variation in NUtE was mostly accounted for by N rates (48 %) and harvest dates (39 %). • NUtE responses were explained by NNI and forage yield. • A NUtE of 29 ± 5.1 kg DM kg−1 N is proposed as a reference value for NNI = 1. Improving nitrogen (N) utilization efficiency (NUtE (kg dry matter (DM) kg−1 N uptake)) is one of the challenges of modern grassland systems in order to improve nitrogen use efficiency. The NUtE is highly variable in response to climate and N supply. Therefore, NUtE must be assessed in relation to the N nutrition index (NNI) and forage yield in pastures growing under different N supplies and environments. The aim of this study was to assess NUtE and NNI in response to different ryegrass genotypes, N supplies and harvest times. Two experiments were conducted in southern Chile for this purpose. In each experiment, treatments were the factorial combination of two hybrid ryegrass cultivars (Shogun and Trojan) and seven N fertilization rates (0, 50, 100, 200, 350, 525 and 700 kg N ha−1 yr−1). A wide range in N uptake, NUtE and NNI were observed (N uptake: 4 – 134 kg N ha−1; NUtE: 20 – 71 kg DM kg−1 N uptake; NNI: 0.23 – 1.43) across experiments. The main sources of variation of the above-mentioned variables were N rates and harvest times. Across experiments, the NUtE was described by a negative power function (R2 = 0.77, P < 0.01) in relation to the NNI and the remaining variability in NUtE was well explained by the forage yield, demonstrating that NUtE depends on the N nutritional status and forage yield. A reference NUtE of 29 ± 5.1 kg DM kg−1 is proposed for grasslands growing at optimal N status (NNI = 1). Therefore, both the NNI and forage yield must be taken into account when interpreting how NUtE responds to genotypes cultivated under different N availabilities and growing conditions. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is a fructan-accumulating plant constituting one of the most important grassland species with high herbage production, nutritive value and digestibility for grazing cattle. Although fructans were reported to be involved in plant defense acting as antioxidants or stress signals, their contribution in root protection is still to be explored. In roots, atypical defense is provided by the "Root Extracellular Trap" or "RET" at the root-soil interface. The molecular composition and structural organization of the RET are essential to provide root defense against pathogen attacks and abiotic stresses. The RET was reported to be mainly composed of polysaccharides (homogalacturonan, xylogalacturonan, xyloglucan) and proteoglycans such as arabinogalactan proteins (AGPs). Our aim is to characterize the RET composition of L. perenne using cell imaging techniques and a wide range of monoclonal antibodies directed against epitopes from cell wall glycomolecules and to investigate the potential presence of fructans. Interestingly, we found that both mucilage and cell wall surface of border cells were enriched in AGP epitopes. An increased amount of the AGP-containing mucilage was produced by L. perenne root tip in response to both elicitor and osmotic stress. Fructan epitopes were also detected in root cap cells and appeared to be released in the RET under stress conditions. Taken together our findings suggest that AGPs together with fructans are involved in root response of L. perenne to environmental stresses. • The root tip of perennial ryegrass produced border cells of different morphologies. • The root extracellular trap (RET) of perennial ryegrass contained abundant mucilage rich in arabinogalactan protein (AGP). • Fructan epitopes are released within the RET in response to PEG-induced osmotic stress and flagellin 22 elicitation. • Fructans, together with AGPs are promising candidates in root response to environmental stress in perennial ryegrass. [ABSTRACT FROM AUTHOR]

Cadmium (Cd) and arsenic (As) are two highly toxic heavy metals and metalloids that coexist in many situations posing severe threats to plants. Our investigation was conducted to explore the different regulatory mechanisms of ryegrass (Lolium perenne L.) responding to individual and combined Cd and As stresses in hydroponics. Results showed that the ryegrass well-growth phenotype was not affected by Cd stress of 10 mg·L-1. However, As of 10 mg·L-1 caused rapid water loss, proline surge, and chlorosis in shoots, suggesting that ryegrass was highly sensitive to As. Transcriptomic analysis revealed that the transcription factor LpIRO2 mediated the upregulation of ZIP1 and YSL6 that played an important role in Cd tolerance. We found that the presence of As caused the overexpression of LpSWT12 , a process potentially regulated by bHLH14, to mitigate hyperosmolarity. Indoleacetic acid (IAA) and abscisic acid (ABA) contents and expression of their signaling-related genes were significantly affected by As stress rather than Cd. We predict a regulatory network to illustrate the interaction between transporters, transcription factors, and signaling transduction, and explain the antagonism of Cd and As toxicity. This present work provides a research basis for plant protection from Cd and As pollution. [Display omitted] • The physiological response of ryegrass suggests its adaptability to Cd, and sensitivity to As. • Cd substitute Fe intake would be mediated by LpIRO2. • Overexpressed LpSWT12 and bHLH14 participates in regulating hyperosmosis induced by As stress. • IAA and ABA signaling is involved in Cd and As stresses resistance. • We establish ryegrass regulatory network in response to combined As and Cd stresses. [ABSTRACT FROM AUTHOR]

The objective of this study was to quantify the farm gate nitrogen (N) offset potential of perennial ryegrass (Lolium perenne L.; PRG) white clover (Trifolium repens L.; WC) swards by comparing the herbage and milk production from dairy farmlets that were simulations of full farming systems. A study was established where 120 cows were randomly assigned to 4 farmlets of 10.9 ha (stocking rate: 2.75 cow/ha), composed of 20 paddocks each. Cows were fed 526 kg of DM of concentrate on average each year. The 4 grazing treatments were PRG-only at 150 or 250 kg of N/ha and PRG-WC at 150 or 250 kg of N/ha. Cows remained in their treatment group for an entire grazing season and were re-randomized as they calved across treatments each year. As cows calved in the spring as standard practice in Ireland, they were rotationally grazed from early February both day and night (weather permitting) to mid-November, to a target postgrazing sward height of 4.0 cm. Mean sward WC content was 18.1% and 15.4% for the 150 and 250 kg of N/ha PRG-WC treatments, respectively over the 3-yr period. When WC was included, lowering the N rate did not reduce pregrazing yield, pregrazing height, or herbage removed, but those factors decreased significantly when WC was absent. Total annual herbage DM production was 13,771, 15,242, 14,721, and 15,667 kg of DM/ha for PRG-only swards receiving 150 or 250 kg of N/ha and PRG-WC swards receiving 150 or 250 kg of N/ha, respectively. In addition, when WC was present, compressed postgrazing sward heights were lower (4.10 vs. 4.21 cm) and herbage allowance (approximately 17 kg/cow feed allocation per cow per day) higher than the high-N control (+ 0.7 kg of DM/cow per day). There was a significant increase in milk production, both per cow and per hectare, when WC was included in PRG swards. Over the 3-yr study, cows grazing PRG-WC had greater milk (+304 kg) and milk solids (+31 kg of fat + protein) yields than cows grazing PRG-only swards. This significant increase in milk production suggests that the inclusion of WC in grazing systems can be effectively used to increase milk production per cow and per hectare and help offset nitrogen use. This result shows the potential to increase farm gate N use efficiency and reduce the N surplus compared with PRG-dominant sward grazing systems receiving 250 kg of N/ha, without negatively affecting milk solids yield or herbage production, thus increasing farm profit by €478/ha. [ABSTRACT FROM AUTHOR]

Several studies have been conducted to improve grazing management and supplementation in pasture-based systems. However, it is necessary to develop tools that integrate the available information linking the representation of biological processes with animal performance for use in decision making. The objective of this study was to evaluate the precision and accuracy of the Molly cow model predictions of ruminal fermentation, nutrient digestion, and animal performance by cows consuming pasture-based diets to identify model strengths and weaknesses, and to derive new digestive parameters when relevant. Model modifications for adipose tissue, protein synthesis in lean body mass and viscera representation were included. Data used for model evaluations were collected from 25 publications containing 115 treatment means sourced from studies conducted with lactating dairy cattle. The inclusion criteria were that diets contained ≥45% perennial ryegrass (Lolium perenne L.), and that dry matter intake, dietary ingredient composition, and nutrient digestion observations were reported. Animal performance and N excretion variables were also included if they were reported. Model performance was assessed before and after model reparameterization of selected digestive parameters, global sensitivity analysis was conducted after reparameterization, and a 5-fold cross evaluation was performed. Although rumen fermentation predictions were not significantly improved, rumen volatile fatty acids absorption rates were recalculated, which improved the concordance correlation coefficient (CCC) for rumen propionate and ammonia concentration predictions but decreased CCC for acetate predictions. Similar degradation rates of crude protein were observed for grass and total mixed ration diets, but rumen-undegradable protein predictions seemed to be affected by the solubility of the protein source as was the intestinal digestibility coefficient. Ruminal fiber degradation was greater after reparameterization, driven primarily by hemicellulose degradation. Predictions of ruminal and fecal outflow of neutral detergent fiber and acid detergent fiber, as well as total fecal output predictions, improved significantly after reparameterization. Blood urea N and urinary N excretion predictions resulted in similar accuracy using both sets of model parameters, whereas fecal N excretion predictions were significantly improved after reparameterization. Body weight and body condition score predictions were greatly improved after model modifications and reparameterization. Before reparameterization, yield predictions for daily milk, milk fat, milk protein, and milk lactose were greatly overestimated (mean bias of 61.0, 58.7, 73.7, and 64.6% of mean squared error, respectively). Although this problem was partially addressed by model modifications and reparameterization (mean bias of 3.2, 1.1, 1.7, and 0.4% of mean squared error, respectively), CCC values were still small. The ability of the model to predict grass digestion and animal performance in dairy cows consuming pasture-based diets was improved, demonstrating the applicability of this model to these productive systems. However, the failure to predict grass digestion based on standard model inputs without reparameterization indicates there are still fundamental challenges in characterizing feeds for this model. [ABSTRACT FROM AUTHOR]

The silicon (Si) uptake system of two ryegrass (Lolium perenne L.) cultivars was characterised by assessing the concentration- and time-dependent kinetics. Additionally, a Si transporter gene was isolated from ryegrass and their expression pattern was analysed. The concentration-dependent kinetics was examined in Jumbo and Nui cultivars supplied with 0, 0.5, 1.0, 2.0, and 4.0 mM Si and harvested at 24 h and 21 d. The time-dependent kinetics was evaluated at 0, 0.5, or 2 mM Si doses after 0, 3, 6, 9, 12, and 24 h. RACE-PCR was performed to isolate a full-length sequence codifying for a Si transporter, and semi-quantitative and quantitative RT-PCR was used to analyse its expression pattern. Differential Si uptake between ryegrass cultivars was found. Moreover, Lineweaver-Burk linearization showed similar V max values between cultivars; however, different K m suggested that Jumbo and Nui may have different affinities for silicic acid. The dissimilarities in K m between cultivars might involve either the differential contribution of known proteins responsible for Si uptake and transport or the involvement of undiscovered Si transporters. We identified a putative Si transporter from ryegrass Nui (LpLsi1), which was only expressed in roots and down-regulated by Si supply. The predicted amino acid sequence of LpLsi1 did not only show a high similarity and close phylogenetic relationship with monocot Si influx transporters but also indicated that it is a membrane protein possessing a high conservation of domains essential for silicic acid selectivity. Our findings provide evidence of LpLsi1 in ryegrass, which supports its high Si accumulation capacity. • Silicon concentration and Si uptake ability is higher in cv. Jumbo than in cv. Nui. • Both ryegrass cultivars exhibit similar V max , but different K m values. • A putative Si transporter, designated as LpLsi1, was isolated from ryegrass cv. Nui. • LpLsi1 has high conservation of domains determining the selectivity for silicic acid. • LpLsi1 is only expressed in roots and down-regulated by Si supply. [ABSTRACT FROM AUTHOR]

Haloxylon ammodendron , a typical xerophyte, tolerates various abiotic stresses and is widely distributed in desert areas. Two PGPR strains, Bacillus sp. WM13-24 and Pseudomonas sp. M30-35, were previously isolated from the rhizosphere of H. ammodendron in Tengger Desert, Gansu province, northwest China. The aim of this study was to investigate the role of M30-35 and WM13-24 in drought stress alleviation of ryegrass (Lolium perenne L.). Under normal condition, both M30-35 and WM13-24 increased shoot fresh and dry weight, chlorophyll content, total nitrogen and phosphorus contents and altered phytohormone distribution compared to control. Moreover, after 7 days of drought stress, WM13–24 and M30-35 enhanced photosynthetic capacity, relative water content, the activities of catalase (CAT) and peroxidase (POD) and proline content, resulted in decreased malondialdehyde (MDA) content, relative membrane permeability (RMP) and H 2 O 2 accumulation; interestingly, the two strains decreased ABA content in leaves. This study demonstrated that the two PGPR strains promoted ryegrass growth and root development via regulating plant hormone distribution and enhanced drought tolerance of ryegrass through improving the activities of antioxidant enzymes, regulating ABA signaling and maintaining plant growth. Our results indicated that PGPR strains from rhizosphere of the desert plant species could be considered as promising bioinoculants for grass plants. • Both strains Bacillus sp. WM13-24 and Pseudomonas sp. M30-35 had plant growth promoting traits. • Both strains improved root system architecture and promoted the growth of ryegrass seedlings. • Both strains enhanced drought tolerance of ryegrass via enhancing antioxidant enzyme activities and regulating ABA signal. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is a widely used cool season turfgrass with outstanding turf quality and grazing tolerance. High temperature is the key factor restricting the distribution of perennial ryegrass in temperate and sub-tropic regions. In this study, we found that one HEAT SHCOK TRANSCRIPTION FACOTR (HSF) class A gene from perennial ryegrass, LpHSFA3 , was highly induced by heat stress. LpHSFA3 is localized in nucleus and functions as a transcription factor. Ectopic overexpression of LpHSFA3 in Arabidopsis improved thermotolerance and rescued heat sensitive deficiency of athsfa3 mutant. Overexpression of LpHSFA3 in perennial ryegrass enhanced heat tolerance and increased survival rate in summer season as evidenced by decreased EL and MDA, increased number of green leaves and total chlorophyll content. LpHSFA3 binds to the HSE region in LpHSFA2a promoter to constitutively activate the expression of LpHSFA2a and downstream heat stress responsive genes. Ectopic overexpression of LpHSFA2a consequently rescued thermal sensitivity of athsfa3 mutant and enhanced thermotolerance of athsfa2 mutant. Perennial ryegrass protoplasts with overexpression of LpHSFA3 and LpHSFA2a exhibited induction of similar subsets of heat responsive genes. These results indicated that transcription factor LpHSFA3 functions as positive regulator of LpHSFA2a to improve thermotolerance of perennial ryegrass, providing further evidence to understand the regulatory networks of plant heat stress response. • LpHSFA3 and LpHSFA2a were significantly induced by heat stresss. • LpHSFA3 improves plant heat tolerance and survival rate in summer season. • LpHSFA3 directly activates the expression of LpHSFA2a. • LpHSFA2a enhances plant heat tolerance. [ABSTRACT FROM AUTHOR]

Forestry and fruit industry is a unique and advantageous industry in Xinjiang, China, and it is an important channel for farmers to increase income. With limited land resources and a shortage of forage in southern Xinjiang, farmers began to establish a fruit-grass interplanting model to improve the comprehensive economic benefits of orchards. The objective of this study was to explore the effects of apple/ryegrass intercropping system on root spatial distribution and competition, and to evaluate the performance of field microclimate, soil physical properties and productivity under intercropping. In the study, three different planting patterns were designed: sole-cropped apple (The spacing of the rows of apple trees was 4.0 m, and the plant spacing was 1.0 m), sole-cropped ryegrass (Strip sowing, row spacing was 0.25 m), and apple/ryegrass intercropping (The distance from apple row to ryegrass row was 1.0 m). Two-year field experiments were conducted to measure the root length density (RLD), specific root length (SRL), interspecific competitiveness index, soil moisture content, organic matter content, air temperature, relative humidity, wind speed, yield, land equivalent ratio (LER) and aggressivity. Compared with sole cropping, intercropping reduced the RLD of apple and ryegrass and increased the SRL of ryegrass. The competition space between apple and ryegrass was concentrated in the soil area of 100 cm horizontally and 0–20 cm vertically, and apple was more competitive than ryegrass. Intercropping increased the content of soil moisture and organic matter and improved the microclimate of farmland, decreased the air temperature, increased the relative humidity of an orchard, and decreased wind speed. Although intercropping reduced ryegrass and apple yield, land equivalent ratio (LER) was 1.27–1.30, indicating that intercropping improved land use efficiency. Root competition led to an uneven distribution of root length density (RLD) and specific root length (SRL). The plasticity of root morphology and root spatial distribution was key to adapting to competition and maximizing the absorption of water and nutrients in apple/ryegrass agroforestry systems. Apple/ryegrass intercropping system maximizes resource utilization and reduces interspecies resource competition. It improved land use efficiency, improved the comprehensive benefits of fruit and grass production. [Display omitted] • The root niche separation of apple and ryegrass reduced the competition for resources. • Intercropping apple and ryegrass increased soil water content and organic matter content. • Intercropping increased the relative humidity of an orchard, decrease the air temperature and wind speed. • Although the yield of ryegrass and apple decreased, intercropping increased land use efficiency. [ABSTRACT FROM AUTHOR]

The temporal profile of methane (CH 4) emissions from ruminants is affected by feed composition and forage type. This study aimed to 1) describe and compare the post-feeding pattern of CH 4 emissions from lambs fed fresh ryegrass substituted with graded levels of forage rape, and 2) to evaluate the association between the magnitude of the variation in CH 4 emission patterns and organic fermentation products quantified in pre- and- post- feeding rumen content samples. Methane emissions were measured at approximately 6 min intervals in respiration chambers from 70 lambs (n = 14 per treatment) fed ryegrass only (FR0) or as a proportion, 0.25 forage rape + 0.75 ryegrass (FR25), 0.50 forage rape + 0.50 ryegrass (FR50), 0.75 forage rape + 0.25 ryegrass (FR75), and forage rape only (FR100). The magnitude of the variability in CH 4 emissions was defined as the ratio of maximum to minimum CH 4 emissions in a 24 h period. This ratio was correlated (P < 0.05) with the proportions of major short chain fatty acids, and calculated hydrogen (H 2) available per unit of glucose fermented (H 2 /GEF), quantified in rumen content samples collected pre- and- post- feeding. The CH 4 emission profile after each feeding followed an asymmetrical positively skewed shape for FR0 to FR75, but not in lambs fed FR100. The lowest CH 4 emission rates were observed before morning feeding which was followed by a CH 4 peak within the 2 h after feeding, and then the CH 4 emissions decreased until the next feeding. In FR100 lambs, the CH 4 emission rate was, unexpectedly, relatively constant after feeding, without any clear CH 4 peaks. The magnitude of the variability in the CH 4 emission rate increased when the pH of rumen contents and H 2 /GEF measured in pre-feeding samples decreased. Including forage rape at 0.75, or greater proportion, in the diet of lambs drastically changed the CH 4 emissions pattern, likely due to a continuous low pH in the rumen which is detrimental for methanogenesis. In conclusion, the daily variation in CH 4 emissions decreased with increasing forage rape inclusion in the diet of sheep and this was associated with a decreasing acetate proportion in the rumen liquid. • Lambs fed 100% forage rape had relatively constant CH 4 emissions throughout the day. • Adding increasing pasture to the forage rape increased the variability of CH 4. • H 2 available per unit of glucose fermented was correlated to the variability of CH 4. [ABSTRACT FROM AUTHOR]

Policy measures have been taken to improve water quality in the Netherlands. These measures include the abolishment of derogation, which allowed dairy farmers to go beyond the maximum application of 170 kg nitrogen (N) from organic fertiliser per hectare, and additional measures of the 7th Nitrates Action program. Grass-clover swards, known for their symbiotic N fixation, could be a strategy to deal with stricter N policies and can potentially improve the environmental sustainability and economic viability of Dutch dairy farms. The aim was to assess the effects of stricter N policies on the farm structure, farm income and environmental performance of a representative Dutch dairy farm on a sandy soil, and to assess the effect of incorporating perennial ryegrass-red white clover (GC rw) swards and perennial ryegrass-white clover (GC w) swards into the grassland management of this farm using a model. A whole-dairy farm linear programming model was used with the objective function to maximize farm income. The model was combined with a farm nutrient balance and life-cycle assessment to determine the impact on nutrient surpluses and greenhouse gas emissions. We modelled a representative Dutch dairy farm with perennial ryegrass (PRG) before and after implementing stricter N policies. Thereafter, the implications of implementing GC rw and GC w swards was assessed. Including the policy measures increased the share of maize land (+12%), decreased the number of dairy cows (-9 cows), reduced farm income (€-18,858 yr-1), led to similar greenhouse gas emissions (∼800 kg carbon dioxide equivalents (CO 2 -eq) per tonne (t) of fat and protein corrected milk (FPCM)), and resulted in a lower N surplus (-65 kg ha-1 yr-1) and phosphate surplus (-4.4 kg ha-1 yr-1) for a scenario with only PRG. The use of GC rw and GC w swards could partly compensate for the reduction in farm income (€+9,255 up to +14,706 yr-1). A combination of PRG, GC rw and GC w resulted in the highest farm income. The use of grass-clover swards only had the most positive effect on greenhouse gas emissions (767 kg CO 2 -eq t-1 FPCM) and N surplus (113 kg ha-1 yr-1). Sensitivity analysis showed the importance of yields and feed characteristics on the obtained farm income. Grass-clover swards might partly compensate for the negative economic consequences of stricter N policies for Dutch dairy farms. Furthermore, implementing grass-clover swards reduced the GHG emission intensity of milk, but not always nutrient surpluses per hectare of farm land. [Display omitted] • Grass-clover swards might be a strategy for dairy farmers to deal with stricter nitrogen policies in the Netherlands. • Economic and environmental effects of stricter nitrogen policies were quantified with a whole farm model. • Number of cows, labour income and nutrient surpluses decreased under stricter policies. • Grass-clover swards improved labour income and carbon footprint but not always nutrient surpluses. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is critical to plants in metal-contaminated soils because it participates in various biochemical reactions during plant growth. However, the mechanisms of P in mitigating the toxicity of heavy metals to ryegrass root is still veiled. In this study, the physiological and biochemical dynamics of the ryegrass root under various cadmium (Cd) and P conditions were investigated in a hydroponic system. Cd stress decreased the length of the ryegrass root, but P application enhanced the root elongation to reduce the Cd concentration in the root. Both Cd and P dosages were positively correlated with hemicellulose 1 content, pectin content, and PME activity, while having a negative effect on cellulose content. Moreover, the addition of 80 mg L−1 P increased the contents of pectin and hemicellulose 1 by 2.5 and 5.8% even with 4 mg L−1 Cd. In addition, P supply increased pectin methylesterbase activity under Cd stress, which further changed the extra-cytoplasmic structures and cell wall composition. Thus, exogenous P promoted the immobilization of Cd onto the cell wall and protected protoplast primarily through indirectly regulating the binding capacity of the root cell wall for Cd. [Display omitted] • P addition significantly increased the length and activity of ryegrass roots. • Cd absorbed by roots was enhanced by P but most Cd was adsorbed by the cell wall. • The polysaccharides content and PME activity were altered by exogenous P. • The dilution and redistribution of Cd induced by P reduced the Cd toxicity in roots. [ABSTRACT FROM AUTHOR]

Due to the increasing occurrence of drought events, drought recovery has become equally important as drought resistance for long-term growth and survival of plants. However, information regarding the mechanism that controls growth recovery of herbaceous perennials is not available. In this study, perennial ryegrass (Lolium perenne) was rewatered after eight-day exposure to three drought intensities simulated by polyethylene glycol-6000. The growth, nonstructural carbohydrates (NSC, i.e. sucrose, glucose, fructose and starch), shoot δ 13C, and activities of enzymes for sucrose conversion were monitored for 24 days after rewatering, allowing investigation of the dynamic of NSCs and its relation with growth in the recovery phase. In response to drought, growth and NSC content decreased mainly in shoot rather than root, and the total dry matter was negatively correlated to shoot δ 13C. After rewatering, the growth of drought-treated groups still lagged behind that of control (CK) group for more than 16 days, but it was no longer correlated to shoot δ 13C, suggesting that the limited growth is caused by non-stomatal factors related to photosynthesis. On day 24 after rewatering, the final growth of drought-treated groups caught up or even exceeded that of CK group, and was accompanied by higher dry weight root to shoot ratio (R/S) and root NSC content, which may facilitate water and nutrient acquisition and emergency of new tillers, respectively. During drought and subsequent recovery, the variation of R/S and root NSC content mainly attributed to root acid invertase rather than leaf sucrose phosphate synthase activity. • Legacy effect of drought stress on perennial ryegrass was caused by non-stomatal constraints on photosynthesis. • Recovery of ryegrass from drought stress was associated with increased R/S and elevated carbohydrate content in roots. • Variations in R/S and carbohydrate content in roots of ryegrass during recovery were related to the activity of root InvA. [ABSTRACT FROM AUTHOR]

We previously generated a high–metabolizable energy (HME) perennial ryegrass (Lolium perenne) by genetically modifying the plant to increase the leaf lipid content. Although substantial progress has been made toward characterizing physiological changes of HME ryegrass, very limited information exists for feeding value and its suitability for adoption into the pastoral system. In this study, independent HME ryegrass lines with a range of elevated leaf lipid concentrations were analyzed for changes in fatty acids and possible associated changes in the broader nutritional profile, including the gross energy, which was found to increase by 6.8%. Because ryegrass is often ensiled and fermentation in the rumen leads to biohydrogenation of fatty acids as well as enteric methane production, we sought to investigate these effects on HME ryegrass. This was achieved by performing mini-scale silos and using an automated gas measurement system to incubate the material in rumen fluid in vitro for 24 h. Our study included treatments comprising 3 independent HME ryegrass genotypes and wild-type control materials prepared fresh and as silage, employing in total 5 incubation studies, using rumen fluids collected from 4 nonlactating Jersey × Holstein cows. At intervals during the incubation, the production of gases, volatile fatty acids, and the degree of biohydrogenation were measured. Statistical data analysis indicated that differences in the nutritional compositions of the ensiled materials largely reflected those of their fresh counterparts. Incubation of both fresh and ensiled HME ryegrass in rumen fluid resulted in: (1) a greater percentage of valuable unsaturated fatty acids compared with the control; (2) a significant reduction of butyrate; and (3) a 10 to 15% decrease in the methane proportion of the total gas production. We conclude that ensiling could be a convenient option for preserving HME as a locally produced high-value supplementary feed; however, large-scale application needs to be investigated. In this paper we discuss the potential use of HME ryegrass to enhancing forage feeding value and the potential environmental benefits to the pastoral agriculture industry. [ABSTRACT FROM AUTHOR]

This study compared the fertiliser effects of different types of liquid anaerobic digestates on the growth of perennial ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.), and on soil's primary plant macronutrients and microbial abundance. A factorial design with seven fertilisers and one control (five liquid anaerobic digestates, undigested cattle slurry, calcium ammonium nitrate (CAN) 27% N, and no fertiliser) and four plant schemes (monocultures of perennial ryegrass and white clover, a mix of both, and bare soil) were tested. Plant (forage yield, leaf area index (LAI), canopy height and root mass) and soil (concentrations of total N, Morgan's extracted P and K) responses were measured, as well as soil bacterial/archaeal (16S) and fungal (18S) gene copy numbers (GCN). Digestates and cattle slurry with different chemical compositions, when balanced in terms of the quantity of dry matter applied, had comparable forage yield responses (p > 0.05), with higher yields than CAN mostly observed in ryegrass and mixed vegetation (p < 0.05). The presence of white clover contributed to higher soil N (p < 0.05). Soil available P was increased by biofertiliser applications (p < 0.05). Soil available K was influenced by the interaction between biofertiliser and type of plant (p < 0.05), with ryegrass/mixed swards showing lower K concentrations than white clover and bare soil. Soil bacterial (16S) GCN responded to the interaction between fertiliser/vegetation (p < 0.05), while archaeal (16S) and fungal (18S) GCN only to the type of vegetation (p < 0.05). The application of anaerobic digestates showed low direct impacts on the microbial GCN of the soil, mostly influenced by type of vegetation. The biofertilisers showed comparable performances and effects, despite substantial differences between their chemical compositions, indicating a possible complex matrix of interactions between fertiliser-plant-soil-environment. • Different types of anaerobic digestates drove comparable forage yield responses. • Ryegrass showed better response to anaerobic digestates fertilisation than white clover. • Anaerobic digestate application had low influence on soil microbial numbers. • The type of vegetation had strong influence on soil microbial numbers. [ABSTRACT FROM AUTHOR]

• Combined application of biochar and plants stimulate the removal of PCBs. • Green garden biochar improved plant growth and microbial count. • Higher levels of PCBs-degrading bacteria were observed in the rhizosphere. • Suitable combination for effective plant-tandem removal of PCBs are presented. Polychlorinated Biphenyls (PCBs) are xenobiotic chlorinated aromatic compounds with high toxicity to both fauna and flora. PCBs can enter the environment through close interactions of multiple environmental matrices such as sediments, soils, water and food web. Biogeochemical cycle of PCBs can transport them far from their initial source of production. The present study aims to investigate the effects of organic and chemical amendments during rhizoremediation of PCBs in aged contaminated soil. Italian ryegrass (Lolium multiflorum) was grown in PCB-contaminated soil, whereas different combinations of two biochar (i.e., beech woodchip and green garden waste) and a surfactant (i.e., sodium dodecyl sulfate) were applied to assess the removal efficiency. The overall system's performance was evaluated based on plant growth, PCBs degradation, and proliferation of PCBs degrading bacteria after 5-months of sowing of ryegrass. We found that PCBs removal was significantly high in the vegetated soils as compared to the un-vegetated soils. Maximum removal (85% of total PCBs load) was observed in the presence of green garden waste biochar whereas less removal was observed with the surfactant application. The observations on PCBs degrading bacteria and plant growth parameters were consistent with the degradation scheme, which suggest the potential role of bacteria in the overall degradation process. We conclude that appropriate combinations of vegetation, soil amendments, and PCB degrading bacteria can help to improve the degradation of PCBs impacted soils. [ABSTRACT FROM AUTHOR]

We evaluated whether phosphorus (P) ameliorates manganese (Mn) excess harmful effects on photosynthetic performance, growth, oxidative stress, and antioxidants in ryegrass. Two perennial ryegrass genotypes, Banquet-II as Mn-resistant and One-50 as Mn-sensitive genotype, were growth under hydroponic conditions subjected to increased P (25, 50, 100, 200 and 400 μM), excess (750 μM) and sufficient Mn (2.4 μM) for 15 days. Growth rate, lipid peroxidation (LP), enzymatic and non-enzymatic antioxidants, photosynthetic parameters, and pigments were determined. Significant reduction of photosynthesis and growth in One-50 was observed under Mn-excess combined with low and adequate P, recovering under greater P-doses. The P concentration of both genotypes was enhanced towards increased P-supply, regardless of Mn treatments. Shoots Mn-concentration remained constant in both genotypes under Mn-excess, independently of P-levels; meanwhile, Banquet-II roots Mn-concentration increased 23% by P-supply. Furthermore, Banquet-II roots showed higher superoxide dismutase (SOD) activity than One-50, which increased towards the highest P dose under sufficient and excess of Mn. A high dose of phosphorus amendment alleviated Mn-toxicity in Mn-sensitive genotype (One-50). Besides, in the Mn-resistant genotype, enhanced plant performance is highlighted, explained by a high Mn-accumulation in roots and increased SOD activity, decreasing Mn translocation to shoots and therefore protecting the photosynthetic apparatus. • High P-supply alleviate Mn-toxicity in the Mn-sensitive genotype. • Mn-resistant genotype enhances plant performance by decreasing Mn translocation to shoots. • Root SOD activity increased in the Mn-resistant ryegrass genotype by P-supply under Mn excess. [ABSTRACT FROM AUTHOR]

Atrazine (ATR) continues being one of the most frequently detected pesticides in natural waters and soils. In this work, an electrokinetic-assisted phytoremediation pot test (EKPR) was performed for the remediation of an atrazine-spiked soil; a low electric voltage gradient (1 V cm−1) with two different electric field operation times (6 and 24 h per day) was used in combination with ryegrass (Lolium perenne L.). EKPR increased up to 27% and 7% the overall ATR removal from soil as compared to natural attenuation and phytoremediation treatments, respectively. ATR soil concentration vs time curves were fitted to a pseudofirst-order kinetic equation, obtaining ATR half-life values of 8.2, 7.1 and 5.4 days for the treatments corresponding, respectively, to 0, 6 and 24 h day−1 of electric current application. It clearly showed that the ATR removal from soils was enhanced by the electric field. ATR plant accumulation was significantly improved with respect to phytoremediation when the electric current was continuously applied throughout the experiment (24 h day−1); most of the ATR residues were accumulated in the shoot biomass of the ryegrass plants. Image 1 • Application of EKPR increased up to 27% and 7% as compared to natural attenuation and phytoremediation treatments. • 11–21% of the initial atrazine was accumulated in the ryegrass tissues. • Approximately 80% of the atrazine was removed in the first 4 days of treatment. [ABSTRACT FROM AUTHOR]

Silicon (Si) has the potential to promote plant yield and improve their insect resistance, but the direct defense mechanisms associated with the effects of Si on forage grasses and its regulation are not known. In this study, the conditions of silica fertilization nutrition (1 and 3 mmol L−1 recorded as low concentration (LC) and high concentration (HC) groups, respectively) were changed during the seed germination period, which did not significantly affect the seed germination of ryegrass. However, the shoot biomass and insect resistance of ryegrass were significantly increased in the HC group. Comparison of the transcriptional results from RNA-seq assays revealed that the accumulation of ryegrass biomass may be closely related to the silicon intervention in photosynthesis, and the metabolic synthesis of lignin, carbohydrates, and hemicellulose. There was an additive effect of silicon concentration on the regulatory effects of ryegrass at the transcriptional level. Meanwhile, 98 and 1291 differentially expressed genes were assigned to the metabolic process in the LC and HC groups, respectively. Metabolomic results combined with LC-MS analysis showed that Si initiated a direct defense network in ryegrass with Phenylpropanoid biosynthesis as the backbone, and Flavonoid, Flavone and flavonol, and Isoflavonoid biosynthesis as important branches. The relative content of phenolics was significantly up-regulated, especially in the HC group, and most of these phenolics were potent SOS substances, closely related to the physiological disturbances suffered by Spodoptera frugiperda , with inhibitory effects on larval body weight. The above results confirm that silicon promotes an increase in ryegrass yield while initiating its direct defense network against insects, and that silicon is an effective supplement in improving ryegrass yield and insect resistance. [Display omitted] • Silicon treatment increased the shoot biological production of ryegrass. • Silicon treatment initiated the direct defense network of ryegrass. • Silicon treatment significantly up-regulated the phenolic content in ryegrass. • Silicon treatment improved insect resistance in ryegrass. [ABSTRACT FROM AUTHOR]

Genotype-by-environment interaction (G×E) is commonly observed in perennial ryegrass species and significantly impacts dry matter yield (DMY) performance across environments. Variation in DMY of perennial ryegrass cultivars and their distinct responses to different environments directly influence the profitability of the Australian dairy industry. In this study, we implemented a separate two-way factor analytic strategy to fit multi-environment-multi-harvest data collected from 18 trials spanning 14 years to account for the G×E effects across complex pasture environments in south-eastern Australia to achieve accurate DMY predictions. Three mega-environments were identified, and the seasonal and environmental DMYs of 126 cultivars or breeding lines (defined by a combination of varieties and endophytes) were predicted. Statistical differences in DMY performance and crossover G×E effects in cultivar rankings were observed among the three mega-environments. Several high-yielding cultivars specific to each mega-environment were also identified. The analysis demonstrated the importance of accounting for G×E effects when predicting the DMY of perennial ryegrass and highlighted the potential for identifying high-yielding cultivars specific to mega-environments. The research rationalizes implementing an appropriate independent pasture trialling system to generate necessary data for the dairy industry and could further facilitate dairy farmers to select suitable cultivars based on their specific environments and perennial ryegrass breeders when accounting for the genetic relationship of cultivars. • G×E impacts perennial ryegrass cultivar rankings and breeding strategies. • Factor analytic model is a robust tool for analysing G×E. • Analysing G×E provides accurate DMY prediction and facilitates identifying high-yielding cultivars. • Identified 3 mega-environments and predicted DMYs for 126 cultivars. • Appling an independent trialling system is necessary to identify environmental-specific cultivars. [ABSTRACT FROM AUTHOR]

Although studies on immobilized microorganisms have been conducted, their performance remains unclear for enhancing plants to remediate cadmium (Cd)-contaminated soil. In this study, a Cd-resistant strain TY-1 with good plant growth promotion traits was immobilized by biochar (BC) or oyster shell (OS) power to strengthen ryegrass to remediate Cd-contaminated soil. SEM-EDS combined with FTIR showed that TY-1 could tolerate Cd toxicity by surface precipitation, and functional groups such as hydroxyl and carbonyl groups might be involved. In the biocomposite treatments, soil pH increased, and the activity of fertility-related enzymes such as dehydrogenase increased by 109.01%–128.01%. The relative abundance of genus Saccharimonadales decreased from 7.97% to 3.35% in BS-TY and 2.61% in OS-TY, respectively. Thus, a suitable environment for ryegrass growth was created. The fresh weight, dry weight, plant height and Cd accumulation of ryegrass in TY treatment increased by 122.92%, 114.81%, 42.08% and 8.05%, respectively, compared to the control. Cd concentration in ryegrass was further increased in BC-TY and OS-TY by 24.14% and 40.23%, respectively. The improvement in soil microcosm and plant biomass forms an ongoing virtuous cycle, demonstrating that using carrier materials to improve the efficiency of microbial-assisted phytoremediation is realistic and feasible. [Display omitted] • A bacterial strain with both Cd resistance and plant-promoting traits was isolated. • Multiple functional groups were involved in Cd resistance and cell immobilization. • The biocomposites significantly improved soil microhabitat and ryegrass growth. • Immobilized strain TY-1 significantly enhanced Cd uptake by ryegrass. [ABSTRACT FROM AUTHOR]

Microplastics pollution in environments has become a major concern and it has been proven to have adverse impacts on plants, so there is an urgent to find approaches to alleviate the detrimental effects of microplastics. In our study, we investigated the influence of polystyrene microplastics (PSMPs) on the growth, photosynthesis, and oxidative defense system changes of ryegrass, as well as the behavior of MPs at roots. Then three types of nanomaterials were applied to alleviate the adverse impact of PSMPs on ryegrass, which were nano zero-valent iron (nZVI), carboxymethylcellulose-modified-nZVI (C-nZVI) and sulfidated nZVI (S-nZVI), respectively. Our results suggested that PSMPs had significant toxicity to ryegrass, leading to decrease of shoot weight, shoot length and root length. Three nanomaterials regained the weight of ryegrass to a varying extent and made more PSMPs aggregate near roots. In addition, C-nZVI and S-nZVI facilitated the entrance of PSMPs into the root and promoted the chlorophyll a and chlorophyll b contents in leaves. Analysis of antioxidant enzymes and malondialdehyde content indicated that ryegrass coped well with the internalization of PSMPs, and all three types of nZVI could alleviate PSMPs-stress in ryegrass. This study elaborates the toxicity of MPs on plants and provides a novel insight into the fixing of MPs by plants and nanomaterials in environments, which needs to be further explored in future research. [Display omitted] • PSMPs decreased biomass, length and photosynthetic pigments of plants. • Three types of nZVI all alleviated the toxicity of PSMPs. • Three types of nZVI all promoted plant growth under exposure of PSMPs. • C-nZVI and S-nZVI facilitated the internalization of PSMPs. • S-nZVI might have a more alleviation on the oxidative stress when exposed to PSMPs. [ABSTRACT FROM AUTHOR]

Grazed grass is the cheapest feed available for dairy cows in temperate regions; thus, to maximize profits, dairy farmers must optimize the use of this high-quality feed. Previous research has defined the benefits of including white clover (Trifolium repens L.) in grass swards for milk production, usually at reduced nitrogen usage and stocking rate. The aim of this study was to quantify the responses in milk production of dairy cows grazing tetraploid or diploid perennial ryegrass (Lolium perenne L.; PRG) sown with and without white clover but without reducing stocking rate or nitrogen usage. We compared 4 grazing treatments in this study: tetraploid PRG-only swards, diploid PRG-only swards, tetraploid with white clover swards, and diploid with white clover swards. Thirty cows were assigned to each treatment, and swards were rotationally grazed at a farm-level stocking rate of 2.75 cows/ha and a nitrogen fertilizer rate of 250 kg/ha annually. Sward white clover content was 23.6 and 22.6% for tetraploid with white clover swards and diploid with white clover swards, respectively. Milk production did not differ between the 2 ploidies during this 4-yr study, but cows grazing the PRG-white clover treatments had significantly greater milk yields (+596 kg/cow per year) and milk solid yields (+48 kg/cow per year) compared with cows grazing the PRG-only treatments. The PRG-white clover swards also produced 1,205 kg of DM/ha per year more herbage, which was available for conserving and buffer feeding in spring when these swards were less productive than PRG-only swards. Although white clover is generally combined with reduced nitrogen fertilizer use, this study provides evidence that including white clover in either tetraploid or diploid PRG swards, combined with high levels of nitrogen fertilizer, can effectively increase milk production per cow and per hectare. [ABSTRACT FROM AUTHOR]

Twenty meroterpenoids with diverse ring systems including five new ones (1 , 2 , 5 , 6 , and 15), together with two new (23 and 24) and two known dioxolanone-type secondary metabolites were isolated from Phyllosticta capitalensis , an endophytic fungus from Cephalotaxus fortunei Hook. Compound 1 was the first example with a 9,14- seco ring A and a five-membered ring B in guignardone derivatives. Compound 2 represented a novel guignardone derivative possessing a 5/7/6/5 ring system with CH 2 -7 attached to C-4 rather than C-6 in ring D. The structures of all new compounds were elucidated using spectroscopic data analyses and electronic circular dichroism comparison. The phytotoxic effects of compounds 1 – 24 on Lactuca sativa and Lolium perenne were evaluated. Compound 22 showed inhibition activity on the shoots growth of L. sativa and L. perenne , as well as the roots growth of L. perenne. Image 1 • Isolation of five new guignardone derivatives and two new dioxolanone-type secondary metabolites from Phyllosticta capitalensis. • Compound 1 represented the first guignardone derivative possessing a bicyclic skeleton. • Compound 2 was a 5/7/6/5 ring system with CH 2 -7 attached to C-4 in ring D. • Compound 5 was an infrequent guignardone derivative with a 5/6/6/5 ring system. • Compound 6 possessed an additional five carbons in chemical structure. [ABSTRACT FROM AUTHOR]

• An overview of the effects of forage type and season on retention time and the fatty acids profile of the rumen fluid of steers grazing a temperate grass, a range of tropical and subtropical grasses and a legume/grass mix. • The native speargrass Heteropogon contortus in dry season had the lowest crude protein and digestibility, which was associated with a low concentration of volatile fatty acids, and longer retention time (20 h). • The retention time of all wet season grasses, including the C3 ryegrass Lolium perenne , was similar, despite some small quantitative significant differences, and similar to legume/grass mix in the dry season. • Total unsaturated fatty acids in rumen fluid was reduced markedly compared to the concentration of the forages with some small differences between forage species. • It was concluded that retention time of wet season grasses was similar across all forage species (8-11 hrs) and would not result in different times for biohydrogenation within the rumen. The effects of forage type and season on retention time (RT) and the fatty acid (FA) profile of the rumen fluid (RF) of steers grazing a range of grasses and a legume/grass mix were evaluated. Four rumen cannulated steers (790 ± 17 kg body weight (BW) grazed individual wet season pastures (herbage mass 2600-6200 kg DM/ha of C3 ryegrass Lolium perenne and C4 grasses pangola Digitaria eriantha , signal grass Brachiaria decumbens , star grass Cynodon dactylon , kikuyu Pennisetum clandestinum , and speargrass Heteropogon contortus in both seasons, and a mixture of leucaena Leucaena leucocephala and green panic Panicum maximum in the dry season. Each grazing period consisted of at least 21 d, followed by a 3 d collection period. On d 22 CrEDTA was used to estimate RT (182 mg Cr/100 kg BW via the cannula) and RF samples were collected at 0, 4, 8, 12, 16, 24, 28, 32 and 48 h after dosing for Cr analysis. Diet crude protein (CP) and dry matter digestibility (DMD) were estimated by faecal NIRS. Concentration of NH 3 N and volatile fatty acids (VFA) in RF was determined at 0, 8 and 16 h after dosing. Dry season speargrass had the lowest CP (18 and 39 g/kg DM in plucked sample (PS) and estimated by faecal NIRS, respectively) and DMD (49%), which was associated with a low NH 3 N (9 mg NH 3 N/L) and VFA concentration (70 mM) in RF, and much longer RT of Cr (20 h) than the other grasses. The RT of Cr of the other wet season grasses was similar across all forage species (8- to 11 hours). Total VFA in RF was lowest for steers grazing dry season grass, intermediate for grasses in the wet season and highest for steers grazing the legume/grass mix. Speargrass had the highest non-glucogenic:glucogenic VFA. Ryegrass had higher CP (190 g/kg DM) and DMD (68%), but steers grazing this pasture had similar NH 3 N concentration in RF to steers grazing kikuyu and leaucaena/grass mix (above 100 mg NH 3 N /L). Palmitic and stearic acid in RF were much higher than in plucked samples, but all grasses had similar total saturated FA in RF with a greater degree of saturation for ryegrass. A higher CLA c 9, t 11 in RF of steers grazing ryegrass most likely resulted from the linoleic content in the forage and the higher intake of ryegrass resulting in accumulation in RF. Total unsaturated FA (TUFA) content of RF was reduced markedly compared to forage samples with some small differences between species indicating an extensive biohydrogenation despite the grass type and season. It was concluded that RT of Cr in the rumen of cattle grazing wet season grasses was similar across all forage species (8 to 11 hours) and would not result in different times for biohydrogenation within the rumen. [ABSTRACT FROM AUTHOR]

The unique properties of ionic liquids make them attractive for a wide range of industrial applications, which makes it easy to be released into the environment and cause water or soil pollution. Phytoremediation of organic contaminants is a safe and important process for removing persistent pollutants from the environment. However, due to they are very chemically stable and potentially toxic to plants, whether they can be removed, assimilated and metabolized by plants remains unknown during phytoremediation process. In this study, ryegrass, Lolium perenne L., was used for imidazolium ionic liquid (1-butyl-3-methylimidazolium bromide, [C 4 mim]+) removal from water. The results show that [C 4 mim]+ could be taken up, accumulated and metabolized by plants in vivo with a high removal efficiency. Most of the [C 4 mim]+ was accumulated in the root tissue, with the root concentration fraction factors ranging from 4.9 to 51.5. Two hydroxylated metabolites 1-(4-hydroxybutyl)-3-methylimidazolium, and 1-(n -butyl)-3-(hydroxymethyl)-imidazolium, and two secondary metabolites were detected in the ryegrass after [C 4 mim]+ uptake. The metabolic mechanism was clarified using density functional theory calculations. Furthermore, [C 4 mim]+ at a high concentration was found to be high toxic to inhibit the growth of ryegrass markedly. In response, some oxidative stress was observed in the metabolic process, as indicated by increasing of catalase, super dismutase and peroxidase activities. Our results suggested that phytoremediation was an efficient technique for ionic liquids treatment from water. Image 1 • Uptake, accumulation and metabolism of [C 4 mim]+ by ryegrass from water were confirmed. • Two hydroxylated metabolites and two secondary metabolites were detected after [C 4 mim]+ uptake. • [C 4 mim]+ metabolic mechanism by ryegrass was elucidated using DFT calculation. • Ryegrass was found to have a great potential for phytoremediation of ionic liquids. [ABSTRACT FROM AUTHOR]

• Trifluralin resistance inheritance in a Lolium rigidum population is determined. • Plants in this population contain the α-tubulin mutation Val-202-Phe. • Resistance is largely inherited as a monogenic, recessive nuclear trait. • Polygenic resistance may also be involved, especially at low herbicide rates. • Recessive resistance has implications in resistance evolution and management. The increasing number of weedy species resistant to dinitroaniline herbicides warrants studies on the evolutionary factors contributing to resistance evolution, including genetic inheritance of resistance traits. In this study, we investigated the genetic control of trifluralin resistance in a well-characterised Lolium rigidum Gaud. population from Western Australia. This population was purified to contain plants homozygous for the Val-202-Phe α-tubulin mutation, and used as the resistant (R) parents and crossed with susceptible (S) parents to produce eight reciprocal F1 families. Trifluralin dose response curves of the eight F1 families indicate that trifluralin resistance in this population is inherited as an incomplete recessive nuclear trait. The F1 plants were crossed within each families to establish eight pseudo-F2 (ψ -F2) families. Segregation ratio of resistance and susceptibility in ψ -F2 families were determined using the discriminating trifluralin rates of 120 and 480 g a.i. ha−1. At 480 g a.i. ha−1 trifluralin, the segregation ratio in almost all ψ -F2 families (except one) was fit to 1:3 (resistance: susceptibility) one recessive gene control model. However, at 120 g a.i. ha−1 trifluralin, the segregation ratios in half of the families did not fit this model, indicating involvement of one or more genes in resistance at the lower rate. These results showed complexity of genetic inheritance of trifluralin resistance in this L. rigidum population possessing the Val-202-Phe α-tubulin mutation. [ABSTRACT FROM AUTHOR]

• Dietary nitrate was supplemented to dairy cows grazing ryegrass pasture. • Milk yield, total DMI and pasture DMI was unaffected by treatment. • Methane emissions were unaffected by treatment. • Rumen fermentation parameters were unaffected by treatment. • Lack of treatment response could be due to high nitrate levels in pasture. Limited studies investigated the effect of dietary nitrate addition as methane (CH 4) mitigation strategy for dairy cows grazing pasture. This study aimed to investigate the effect of dietary nitrate addition on daily enteric CH 4 emissions, production performance and rumen fermentation of multiparous Jersey cows grazing perennial ryegrass pasture (containing approximately 7.3 g of nitrate/kg of dry matter (DM)). Thirty-two intact and eight rumen-cannulated multiparous Jersey cows were subjected to a replicated 2 × 2 Latin square design with 16 intact cow replicates and four rumen-cannulated cow replicates supplemented with one of two concentrates containing either urea (urea treatment), or urea and nitrate (nitrate treatment) as nonprotein nitrogen source (NPN; containing 0.3 and 15.2 g of nitrate/kg of DM, respectively). Concentrates were formulated to be isonitrogenous and isoenergetic, and was fed at 5.4 kg of DM/cow per d along with a strict daily herbage allowance of 14 kg of DM/cow. Cows were gradually adapted to concentrates over a 3-wk period. Total nitrate intake was 5.2 and 9.7 g of nitrate/kg of DM for the urea and nitrate treatment groups, respectively. Daily enteric CH 4 emissions of 28 cows were measured with the sulphur hexafluoride tracer gas technique for six consecutive days during each experimental period with parallel total DM intake (DMI) estimates. Pasture DMI was calculated from faecal output and pasture digestibility using TiO 2 and indigestible neutral detergent, respectively. Total DMI (18.1 and 17.8 kg/d), milk yield (19.0 and 18.9 kg/cow per d) and daily CH 4 emissions (400 and 405 g/d) were unaffected by dietary treatment for the urea and nitrate group, respectively. Total milk solids content (135 vs. 133 g/kg), milk lactose content (47.3 vs. 46.7 g/kg) and milk urea nitrogen concentration (MUN; 12.6 vs. 11.6 mg/dL) were higher for the nitrate group. Rumen fermentation parameters such as volatile fatty acid profile, ammonium nitrogen, and DM and fibre disappearance were unaffected by treatment. Minor effects on ruminal pH were observed with an increasing tendency towards the nitrate group. In this study, dietary nitrate supplementation was not an effective CH 4 mitigation strategy for dairy cows grazing perennial ryegrass. This can be ascribed to the unforeseen high nitrate content of the grazed pasture causing a relative small margin in total nitrate intake between the urea and nitrate treatment diets. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • In this paper, a new method for preparing biochar-modified vegetation concrete is presented. • The porosity, permeability and planting capacity of vegetation concrete were studied. • Different biochar contents have different effects on physical properties and planting capacity. • According to the growth of ryegrass, an optimal mix proportion of biochar-modified vegetation concrete was recommended. Abstract Vegetation concrete is an effective material to beautify the landscape, reduce pollution and protect the environment. To further improve the plant compatibility of vegetation concrete, this paper recommends an improved method of adding biochar particles to vegetation concrete. In this research, different masses of biochar were mixed into concrete to study the trend in porosity, permeability and plant compatibility. According to the growth status of three types of common grass species, ryegrass was selected as the best grass species in this study. As the content of biochar increased, the porosity and permeability coefficient of vegetation concrete continued to decrease, while the effect of biochar on plant growth promotion at first showed an increase to the maximum and then a gradual decrease. When the biochar content was 5 kg/m3, ryegrass showed the best growth. Compared with the experimental group of vegetation concrete without biochar, the plant height, root length and germination rate increased by 22.2%, 21.1% and 12%, respectively, on day 25, and the compressive strength also increased slightly. Therefore, adding a suitable amount of biochar can improve the characteristics of vegetation concrete. Furthermore, the optimum mix proportion of biochar-modified vegetation concrete was recommended. [ABSTRACT FROM AUTHOR]

Highlights • Wheat and annual ryegrass were grown with two [CO 2 ], and two water levels. • Grain yield, protein content, total grain reducing power and phenolics were measured. • Annual ryegrass competition increased wheat grain protein content under both [CO 2 ]. • Grain yield decreased (by 35%) with annual ryegrass competition. • Total grain reducing power and phenolic content were significantly altered by both treatments. Abstract Annual ryegrass is one of the most serious, costly weeds of winter cropping systems in Australia. To determine whether its competition-mediated plant defence mechanisms effect on wheat grain quality, wheat (cv. Yitpi) and annual ryegrass were grown under two levels of CO 2 (400 ppm; (a[CO 2 ]) vs 700 ppm; (e[CO 2 ]), two levels of water (well-watered vs drought) and two types of competition (wheat only; (W), and wheat × annual ryegrass; (W × R) with four replicates. The competition × [CO 2 ] interaction had a significant effect on wheat grain protein content, where it was increased in W × R under both e[CO 2 ] (+17%) and a[CO 2 ] (+21%). Grain yield, total grain reducing power and phenolic content were significantly affected by [CO 2 ] × drought × competition. In a summary, annual ryegrass competition significantly altered the wheat grain quality under both [CO 2 ] levels (depending on the soil water level), while also decreasing the grain yield. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Ryegrass early sowing resulted in earlier forage offering and a decreased soil nitrate content. • Ryegrass early sowing decreased annual N 2 O emissions by 18.5%. • N 2 O emissions were lower for ICL than for the grain production system. Abstract Ryegrass early sowing at the beginning of soybean grain maturation (stage R7) results in an earlier offering of forage for animals in integrated crop-livestock (ICL) systems. In addition, early sowing may decrease N 2 O emissions compared to ryegrass sowing after soybean harvest, although this possibility requires further study. We performed a two-year study to evaluate the effects of ryegrass early sowing in an ICL system under subtropical conditions. The following treatments were tested: (1) ryegrass early sowing into R7 soybean (ICL-I); (2) ryegrass sowing after soybean harvest (ICL-II); and (3) continuous cultivation for grain production with soybean/canola and soybean/wheat successions (CC). We measured the N 2 O fluxes, soil NH 4 + and NO 3 − dynamics, grain yield and forage production. The soybean grain yield was not affected by the ICL and CC systems. Forage was offered earlier in the ICL-I system than in the ICL-II system over the two-year period. Ryegrass forage production was two times higher in the ICL-I system than in the ICL-II system during the first year (5.0 vs 2.3 Mg dry matter ha-1). Ryegrass early sowing efficiently decreased the soil NO 3 − content from soybean stage R7 until the end of the ryegrass cycle. Cumulative N 2 O emissions were positively correlated with nitrate intensity (R2 = 0.95), indicating that practices that decreased the soil NO 3 − accumulation, such as ryegrass early sowing, contributed to decreased N 2 O emissions. The mean cumulative N 2 O emissions for the two-year period was 18.5% lower for ICL-I than for ICL-II (821.3 vs 1007.2 g N-N 2 O ha-1). The cumulative N 2 O emissions were 24 and 21% lower for ICL than for CC for the first and second years, respectively. The present study shows that ryegrass early sowing is an alternative that can decrease annual N 2 O emissions and may contribute to improving the greenhouse gas balance in ICL systems compared to that in grain production systems. [ABSTRACT FROM AUTHOR]

Abstract In the present work, for the first time in the literature, the relationship between the degree of air pollution, the physiological state of the plants and the allergenic capacity of the pollen they produce has been studied. The physiological state of Lolium perenne plants growing in two cities with a high degree of traffic, but with different levels of air pollution, Madrid and Ciudad Real, have been explored. The photosynthetic efficiency of the plants through the emission of fluorescence of PSII, the degree of oxidative stress (enzymatic activities related to the ascorbate-glutathione cycle), the redox state (reduced and oxidized forms of ascorbate and glutathione) and the concentration of malondialdehyde have been evaluated. During the development period of the plants, Madrid had higher levels of NO 2 and SO 2 than Ciudad Real. The greater degree of air pollution suffered by Madrid plants was reflected on a lower photosynthetic efficiency and a greater degree of oxidative stress. In addition, NADPH oxidase activity and H 2 O 2 levels in pollen from Madrid were significantly higher, suggesting a likely higher allergenic capacity of this pollen associated to a higher air pollution. Highlights • Air pollution level impact in photosynthesis efficiency of Lolium perenne plants. • Higher air pollution levels provoke greater oxidative stress in L. perenne plants. • Air pollution level alter ascorbate-glutathione redox state in L. perenne plants. • Higher air pollution levels increase NADPH oxidase activity in pollen. • Higher air pollution levels increase H 2 O 2 level in pollen. [ABSTRACT FROM AUTHOR]

Highlights • Tri-axial accelerometer sensors are widespread to monitor behaviour of animals. • Discriminant analysis classifies feeding behaviours in grazing sheep. • Sampling the three axes of acceleration produces an enormous quantity of data. • An epoch of aggregation window can reduce the quantity of data. • The 30 s epoch length yields the most accurate classification in grazing sheep. Abstract Monitoring behaviour of grazing animals is important for the management of grazing systems. A study was run to discriminate between the main behaviours (grazing, ruminating and other activities) of sheep at pasture wearing a halter equipped with an accelerometer (BEHARUM device), and to identify the epoch setting (5, 10, 30, 60, 120, 180 and 300 s) with the best performance. The BEHARUM device includes a three-axial accelerometer sensor and a force sensor positioned under the lower jaw of the animal. The halter was fitted to eight Sarda dairy sheep that rotationally grazed either a spatial association (mixture) or a time association of berseem clover (Trifolium alexandrinum L.) and Italian ryegrass (Lolium multiflorum Lam.) for 6 h day−1. The behaviour of the animals was also video-recorded. The raw acceleration and force data were processed for each epoch setting to create 15 variables: the mean, variance and inverse coefficient of variation (ICV; mean/standard deviation) per minute for the X-, Y-, Z-axis and force, and the resultant. Multivariate statistical techniques were used to discriminate between the three behavioural activities: canonical discriminant analysis (CDA), and discriminant analysis (DA). To validate the derived discriminant functions, a bootstrap procedure was run. To evaluate the performance of DA in discriminating between the three activities, the sensitivity, specificity, precision, accuracy and Coehn's k coefficient were calculated, based on the error distribution in assignment. Results show that a discriminant analysis can accurately classify important behaviours such as grazing, ruminating and other activities in sheep at pasture. The prediction model has demonstrated a better performance in classifying grazing behaviour than ruminating and other activities for all epochs. The 30 s epoch length yielded the most accurate classification in terms of accuracy and Coehn's k coefficient. Nevertheless, 60 and 120 s may increase the potential recording time without causing serious lack of accuracy. [ABSTRACT FROM AUTHOR]

Highlights • Sward chemical and structural characteristics influence varietal grazing efficiency. • Tetraploid varieties have superior grazing performance. • Key selection criteria for grazing varieties are DMD, FLL and tiller mass. • Significant variation to allow for improvements in performance. • Interaction of plant-animal is essential. Abstract Herbage utilisation is of primary importance to grassland farmers due to its strong association with profit, yet it is not assessed in routine grass evaluations. On commercial grassland farms, grazing efficiency of varieties is believed to influence their level of herbage utilisation. To understand grazing efficiency the interaction between plant and animal is critical; mechanically simulated grazing protocols are limited in the information they provide. The objective of this paper was to further understand the grazing efficiency of perennial ryegrass varieties by identifying grazing traits which can be used as selection criteria by breeders striving to develop varieties with improved herbage utilisation. Fifty-five perennial ryegrass varieties, both diploid and tetraploid with intermediate and late heading dates, were sown in plots (3 m × 7 m; 21 m2) following a randomised block design with three replicates per variety. Swards were rotationally grazed by lactating dairy cows during the 2015 and 2016 grazing seasons. Sward structural, morphological, and chemical characteristics were measured and related to grazing efficiency, as measured by post-grazing sward height. These data were analysed using the PROC MIXED procedure to test the fixed effects of traits and the GLM procedure to test their relationships with grazing efficiency. Varieties were shown to differ in their level of grazing efficiency (p < 0.001). Tetraploid varieties had significantly (p < 0.001) greater grazing efficiency than diploids recording post-grazing sward heights of 3.8 and 4.1 cm, respectively. Increased free leaf lamina (p < 0.001), tiller mass (p < 0.05) and dry matter digestibility (p < 0.01) were shown to significantly improve grazing efficiency of varieties. This study has identified free leaf lamina, tiller mass and dry matter digestibility as key selection criteria for plant breeders to base their developments upon if grazing efficiency is imported into their breeding programmes. [ABSTRACT FROM AUTHOR]

Soil acidity, associated with aluminium (Al) toxicity and low phosphorus (P) availability, is considered the most important problem for agricultural production. Even though the Al-P interaction has been widely investigated, the impact of P-nutrition on Al-toxicity still remains controversial and poorly understood. To elucidate further insights into the underlying mechanisms of this interaction in ryegrass ( Lolium perenne L.), P uptake, antioxidant responses and the gene expression of phosphate transporters were determined. Two ryegrass cultivars with different Al resistances, the Al-tolerant Nui cultivar and the Al-sensitive Expo cultivar were hydroponically grown under low (16 μM) and optimal (100 μM) P doses for 16 days. After P treatments, plants were exposed to Al doses (0 and 200 μM) under acidic conditions (pH 4.8) for 24 h. Al and P accumulation were higher in the roots of Nui than that of Expo. Moreover, lower Al accumulation was found in shoots of Nui independent of P supplies. Oxidative stress induced by Al-toxicity and P-deficiency was more severe in the Al-sensitive Expo. Expression levels of L. perenne phosphate transporters were higher in Nui than they were in Expo. While LpPHT1 expression was up-regulated by P deficiency and Al toxicity in both cultivars, LpPHT4 expression only increased in the Al-tolerant cultivar. This report shows that the higher Al-tolerance of Nui can be attributed to a greater antioxidant system under both P conditions. The observation of higher P and Al accumulation in roots of Nui might indicate that the Al-tolerance of Nui is a consequence of Al immobilization by P mediated by the high expression of phosphate transporters. [ABSTRACT FROM AUTHOR]

The use of urine, and urine-derived products can supplement chemical fertilisers. There is little information on the use of urine products in agriculture particularly in South Africa. A laboratory incubation experiment was conducted to determine effects of urine-derived sources on nitrogen (N) release in soil. A 5 × 2 factorial in a completely randomised design was used with two soils, differing in clay and carbon contents, and five nitrogen (N) sources; unamended control, urine, struvite effluent, stuvite + struvite effluent, nitrified urine concentrate. A follow up tunnel pot trial was conducted to determine effects of the urine-derived N sources on dry matter production of perennial ryegrass. The experiment was conducted with the Cartref soil as a 6 × 2 factorial in a completely randomised design, with the same N sources as in the incubation experiment, applied either once-off or split, replicated three times. In the Cartref soil (lower clay and C), ammonium- N declined from 1000 to about 3 mg/kg from day one to day 70, while nitrate- N increased significantly from 0.3 mg/kg to about 400 mg/kg during the same period. Conversely, ammonium-N declined from 100 mg/kg to 8.5 mg/kg in the Inanda soil (higher clay and C), while nitrate- N did not significantly increase. Split application of urine derived N sources resulted in higher cumulative dry matter (873–993 kg/ha) than once-off application (602–727 kg/ha). When split applied only struvite effluent resulted in higher drymatter than struvite effluent + struvite, while once-off application resulted in higher drymatter in the NUC (725 kg/ha) and urine (707 kg/ha) than struvite effluent (602 kg/ha) and struvite effluent + struvite (663 kg/ha). The study indicate that urine derived nitrogen sources, particularly nitrified urine concentrate, can release nitrogen in soil and increase drymatter production of perennial ryegrass, particularly with split application. [ABSTRACT FROM AUTHOR]

Fragipan horizons are naturally occurring impermeable layers found in certain soil types which constrain crop yields. While abundant literature exists regarding the processes of fragipan genesis, there is little recognition given to potential alterations in the pan with surface management, particularly important in light of the fact that these horizons can occur near the surface. We collected soil cores from a Zanesville silt loam (Typic Fragiudalf) and seeded them to annual ryegrass in the greenhouse and determined relevant soil properties after one growing cycle. The presence of ryegrass lowered bulk densities in the Btx1 and Btx2 horizons by 8% and 6% when compared with the counterpart horizons in the control, suggesting an increase in porosity. These findings were paralleled by a 62% and 52% reduction in tensile strength of ryegrass-grown aggregates in these same horizons when compared with control aggregates. These trends are likely due in part to solubilization of cementing agents by ryegrass root exudates. Glycolate, azelaic acid, and diphenolics appeared as components of the water soluble organic fraction (WSOC) pool and the diphenolics were in greater concentrations in ryegrass soil cores. Diphenolic concentrations were associated with elevated water-soluble aluminum and iron levels, suggesting that ryegrass might be solubilizing these cementing agents and affecting bulk density. Biological drilling by ryegrass roots might also be involved to increase porosity in fragipan horizons. Our findings raise questions about the ability of ryegrass to ameliorate impermeable subsurface fragipan horizons and how the improvement in porosity might impact subsequent row crop production. [ABSTRACT FROM AUTHOR]

Chlorophyll (Chl) degradation leads to leaf senescence and adversely affects biomass production of forage grasses and aesthetic appearance of turfgrasses. The objectives of this study were to characterize the function of a Chl catabolic gene, NON-YELLOW COLORING 1 ( LpNYC1 ), and to understand its transcriptional regulatory pattern involved in leaf senescence in perennial ryegrass ( Lolium perenne L.). The LpNYC1 was initially cloned using the RACE-PCR method. Its encoded protein was localized in chloroplasts and its expression pattern was correlated with the progression of leaf senescence. LpNYC1 shared the same biological function with Arabidopsis NYC1, as overexpression of its encoding gene accelerated chlorophyll degradation in Nicotiana benthamiana and rescued the stay-green phenotype of the Arabidopsis nyc1 null mutant. A yeast one-hybrid cDNA library was prepared from senescent leaves of perennial ryegrass. Using the LpNYC1 promoter as bait, five putative transcription factors upstream of LpNYC1 were pooled out using this method, among which three (LpABI5, LpABF3, and LpEIN3) were orthologous to Arabidopsis transcription factors involved in the ABA and ethylene signaling pathways. The expression of LpNYC1 was highly inducible by ABA and ethephon (ethylene releasing reagent) but was suppressed by treatment with AVG (ethylene biosynthesis inhibitor). Furthermore, LpABI5, LpABF3, LpEIN3 directly activated the expression of LpNYC1 by binding to its promoter. The current result laid the groundwork for future in-depth analysis of the molecular regulation of LpNYC1 and Chl metabolism during leaf senescence in perennial grass species. [ABSTRACT FROM AUTHOR]

Bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil is often limited by inadequate microbial activity and/or low PAH bioavailability. A pot experiment was performed with an aged contaminated arable soil to explore the remediation potential of ryegrass and lignin, which are believed to improve microbial degradation, as well as the biosurfactant rhamnolipid. On average, the concentration of 15 priority PAHs was reduced by 41.7% in the combined ryegrass, lignin and rhamnolipid treatment after 90 days. In contrast, there was no reduction in PAH concentration when each treatment was used alone. The rhamnolipid was beneficial for successful remediation, as shown by the lack of PAH transformation in all non-rhamnolipid treatments. The total amount of PAHs that accumulated in ryegrass biomass was less than 0.1% of the initial amount in the pot. When the theoretical estimate of plant uptake was considered, it suggested that rhizoremediation rather than direct uptake contributed to PAH dissipation. High-throughput sequencing analysis demonstrated that lignin addition substantially changed the fungal and bacterial communities; however, there was no indication that lignin selected for known bacterial PAH degraders. Nevertheless, a [ 14 C]benz(a)anthracene-spiked microcosm experiment showed that lignin amendment led to enhanced PAH mineralization and nonextractable residue formation. Taken together, these findings highlight the importance of selecting bioremediation treatments that can simultaneously stimulate microbial activity and increase PAH bioavailability to achieve remediation effectively. Treatments incorporating rhizoremediation, biostimulation and biosurfactant addition hold promise for detoxifying aged PAH-contaminated agricultural soil. [ABSTRACT FROM AUTHOR]

Lignocellulosic biomass from non-food crops is an attractive renewable source of sugars. These sugars can be used as feedstock for the microbial production of different industrially relevant compounds. Delignification of lignocellulosic biomass is a major challenge in sugar extraction. In the present study, ryegrass biomass (non-food), which is high in carbohydrates, was pre-treated with the anionic surfactant sodium dodecyl sulphate (SDS) for effective delignification. Enzymatic hydrolysis of the pre-treated biomass led to the extraction of high sugar levels compared with the raw biomass. Furthermore, these sugars were used for the production of poly-hydroxyalkanoates (PHA), which is an alternative to synthetic polymers. Ryegrass treated with 1% SDS solution at 180 °C showed the maximum delignification. This pre-treated biomass was characterised by TGA, FTIR and SEM and showed successful lignin removal. Enzymatic hydrolysis of the resultant pre-treated biomass showed 87% conversion into sugars and was used as a carbon source for the production of medium chain length (mcl) PHAs using two Pseudomonas strains. Both strains accumulated approximately 30% of their cell dry weight in mcl-PHAs. Hence, this study shows for the first time that surfactant pretreatment is effective for lignin solubilisation; this process increased the biomass surface area and improved enzyme actions, resulting in higher sugar extraction. [ABSTRACT FROM AUTHOR]

Sustainable technologies for the recovery of rare earth elements (REE) from waste need to be developed to decrease the volume of ore mining extractions and its negative environmental consequences, while simultaneously restoring previously impacted lands. This is critical due to the extensive application of REE in everyday life from electronic devices to energy and medical technologies, and the dispersed distribution of REE resources in the world. REE recovery by plants has been previously studied but the feasibility of REE phytoextraction from a poorly soluble solid phase (i.e., nanoparticles) by different plant species has been rarely investigated. In this study, the effect of biostimulation and bioaugmentation on phytorecovery of REE nanoparticles (REE-NP) was investigated by exposing ryegrass seeds to REE-NP in hydroponic environments. This was studied in two sets of experiments: bioaugmentation (using CeO 2 nanoparticles and Methylobacterium extorquens AM1 pure culture), and biostimulation (using CeO 2 or Nd 2 O 3 nanoparticles and endogenous microorganisms). Addition of M. extorquens AM1 in bioaugmentation experiment including 500 mg/L CeO 2 nanoparticles could not promote the nanoparticles accumulation in both natural and surface-sterilized treatments. However, it enhanced the translocation of Ce from roots to shoots in sterile samples. Moreover, another REE-utilizing bacterium, Bacillus subtilis , was enriched more than M. extorquens in control samples (no M. extorquens AM1) , and associated with 52% and 14% higher Ce extraction in both natural (165 μg/g dried-plant) and surface-sterilized samples (136 μg/g dried-plant), respectively; showing the superior effect of endogenous microorganisms' enrichment over bioaugmentation in this experiment. In the biostimulation experiments, up to 705 μg/g dried-plant Ce and 19,641 μg/g dried-plant Nd could be extracted when 500 mg/L REE-NP were added. Furthermore, SEM-EDS analysis of the surface and longitudinal cross-sections of roots in Nd 2 O 3 treatments confirmed surface and intracellular accumulation of Nd 2 O 3 -NP. These results demonstrate stimulation of endogenous microbial community can lead to an enhanced REE phytoaccumulation. [Display omitted] • Engineered rare earth elements (REE) nanoparticles phytoextraction was investigated. • Biorecovery of solid phase REE leads to less ore mining and leaching treatments. • Biostimulated ryegrass seeds could recover both Ce and Nd nanoparticles. • REE-utilizing microorganisms were enriched and promoted REE phytoextraction. • Ryegrass can be used as a landscape and resource recovery system, simultaneously. [ABSTRACT FROM AUTHOR]

Once littered, disposable e-cigarettes present a complex type of waste in the environment. They typically contain a lithium battery, electronics to produce vapour and remnant e-liquid, all of which could leach into the environment. The effects of littered e-cigarettes are not well understood, and they have not been tested in terrestrial ecosystems. To address this, an experiment was set up to assess how leachate from e-cigarettes with or without a battery, but also e-liquid on its own can alter fundamental physical characteristics of Lolium perenne (perennial ryegrass) when irrigated with contaminated water. After 31 days, shoot length of L. perenne was not measurably affected, but the biomass was significantly reduced by 30% when e-liquid, and 24% when leachate from intact e-cigarettes was present compared to control plants. Plants grown with leachate or e-liquid displayed a significant level of early senescence of leaf apices, and the chlorophyll content was increased. Furthermore, root biomass was significantly less (29–46%) compared to the control. Leachate from used disposable e-cigarettes can affect the performance of plants when entering the soil ecosystem, therefore stricter regulations are needed to prevent this new type of electronic litter from becoming more widespread. [Display omitted] • E-cigarettes are increasingly littered in the environment where they can be hazardous. • E-liquid and leachate from e-cigarettes caused Lolium perenne to senesce within 31 days. • E-liquid and leachate from e-cigarettes affected above and belowground biomass of L. perenne. [ABSTRACT FROM AUTHOR]

Little is known regarding how biochars' feedstock and pyrolysis temperature affect soil function and plant growth. To address this gap in knowledge, 12 biochars (walnut shells, corn cobs, corn straws, and rice straws were separately pyrolyzed at 250, 400, and 600 °C for 4 h) were applied to soil from an indigenous coking site with application rate of 2.5% (w/w) in a pot experiment to determine the impact of biochar types on macro-nutrients (total and available N, P, and K) and ryegrass growth in the soil from an indigenous coking site. Generally, the total N, P, and K in the soil was not significantly different from that of the control group. However, biochars decreased the available N from 21.76 mg·kg − 1 for the control to 14.96 mg·kg − 1 . Corn straw and rice straw biochars increased the available P from 2.14 mg·kg − 1 for the control to 28.35 mg·kg − 1 , specifically at higher pyrolysis temperature, while walnut shell and corn cob biochars had little influence on it regardless of pyrolysis temperature. Biochars increased the available K from 173.58 mg·kg − 1 for the control to 355.64 mg·kg − 1 , varying as their feedstocks of corn cob > rice straw > corn straw > walnut shell and increasing with the increase of pyrolysis temperature. Correlation analysis suggests that it is responsible for the competition of soluble cations from biochars with K for adsorption sites on the soil surface. Biochars increased the ryegrass biomass from 0.07 g·pot − 1 for the control to 0.16 g·pot − 1 , with the generally most effective stimulation by biochars produced at 400 °C. Ryegrass biomass had obviously positive correlation with available K, indicating its essential role in the growth of ryegrass in the studied soil. [ABSTRACT FROM AUTHOR]

Ryegrass pasture is characterised as having a high crude protein content (214–298 g/kg DM) but a low fibre content (390–550 g NDF/kg DM). Additional supplementation of energy based concentrates is provided to ensure profitable milk production. The high starch content in these supplements could negatively impact the rumen environment; lowering rumen pH and inhibiting pasture degradability. Dried apple pomace (DAP) is a possible alternative energy source to maize for dairy cows grazing pasture; however, little information is available on the effectiveness of this high fibre by-product for milk production from pastures. The aim of this study was to determine the potential use of DAP as an energy source for Jersey cows grazing ryegrass pasture. Seventy six lactating Jersey cows were blocked according to milk yield, days in milk and lactation number. Cows within blocks were randomly allocated to one of four treatments. Treatments were: NDAP-0% dried apple pomace and 75% maize; LDAP-25% dried apple pomace and 50% maize; MDAP-50% dried apple pomace and 25% maize; HDAP-75% dried apple pomace and 0% maize. Cows received 6 kg as is of the allocated concentrate in the milking parlour daily. Cows of all four treatments strip grazed perennial ryegrass pasture over an area of 8.6 ha. Additionally, four ruminally cannulated cows were used to monitor treatment effect on rumen activity and health. Each cow was randomly allocated to one of four treatments and subjected to a four period crossover. The 4% fat corrected milk yield was lower for cows in treatment HDAP than for cows in treatments NDAP and LDAP, differences ranging between 1.7 and 2.3 kg/day. The milk protein content was lowest for cows in treatments NDAP and MDAP, showing a cubic trend (P = 0.005), with milk fat content increasing as the level of maize substituted by DAP increased. Treatment had no effect on rumen metabolism parameters. Replacing maize with DAP is a viable option for cows grazing ryegrass pasture; however, the decrease in 4% fat corrected milk yield and the potential economic impact should not be overlooked. [ABSTRACT FROM AUTHOR]

A floating ryegrass mat was constructed for low-pollution wastewater treatment during a low-temperature season. Plastic tanks were used as containers, and filled with low-pollution wastewater with low or high nitrogen concentrations, and with and without the floating ryegrass mat, creating four treatments in total (Group Low, Control Low, Group High and Control High). The experiment was conducted for 61 days. The results showed that the removal rates of TN, NH 4 + , and NO 3 − were considerably higher in Group Low and Group High than in the controls. The removal rates of TN were 86.8–88.8% in Group Low and 95.0–96.1% in Group High, while the removal rates of NH 4 + were 91.1–92.5% in Group Low and 97.9–99.1% in Group High. Meanwhile, the COD values were in the range of 5.5–20.9 mg/L in Group Low and 7.0–26.7 mg/L in Group High, which were relatively higher compared to the controls. The higher COD/N ratios in Group Low and Group High might enhance nitrogen removal. Overall, the ratio of plant assimilation to TN input was estimated to be 33.0% and 47.6% in Group Low and Group High, respectively. The ryegrass mat displayed advantages such as easy transport and high seedling survival rate. The constructed floating ryegrass mat effectively reduced nitrogen concentration. Therefore, this technique can be an alternative approach for low-pollution wastewater treatment. [ABSTRACT FROM AUTHOR]

Land use change driven alteration of microbial communities can have implications on belowground C cycling and storage, although our understanding of the interactions between plant C inputs and soil microbes is limited. Using phospholipid fatty acids (PLFA's) we profiled the microbial communities under two contrasting UK perennial bioenergy crops, Short Rotation Coppice (SRC) willow and Miscanthus Giganteus (miscanthus), and used 13 C – pulse labelling to investigate how recent carbon (C) assimilates were transferred through plant tissues to soil microbes. Total PLFA's and fungal to bacterial (F:B) ratios were higher under SRC willow (Total PLFA = 47.70 ± 1.66 SE μg PLFA g −1 dry weight soil, F:B = 0.27 ± 0.01 SE) relative to miscanthus (Total PLFA = 30.89 ± 0.73 SE μg PLFA g −1 dry weight soil, F:B = 0.17 ± 0.00 SE). Functional differences in microbial communities were highlighted by contrasting processing of labelled C. SRC willow allocated 44% of total 13 C detected into fungal PLFA relative to 9% under miscanthus and 380% more 13 C was returned to the atmosphere in soil respiration from SRC willow soil compared to miscanthus. Our findings elucidate the roles that bacteria and fungi play in the turnover of recent plant derived C under these two perennial bioenergy crops, and provide important evidence on the impacts of land use change to bioenergy on microbial community composition. [ABSTRACT FROM AUTHOR]