Lolium Perenne Research Articles

Phytoremediation strategies for the reclamation of tailings and mining soils in an active open-pit site.

Phytoremediation strategies for the reclamation of tailings and mining soils in an active open-pit site.

Can oxidative potential be a plant risk indicator for heavy metals contaminated soil? Analysis of ryegrass (Lolium perenne L.) metabolome based on machine learning.

Evaluating the plant risk of soil pollution by plant physiological indices usually requires a long cycle and has significant uncertainty. In this study, oxidative potential (OP) of the in situ heavy metal contaminated soils was measured by the dithiothreitol method. The oxidative stress response of the model plant ryegrass (Lolium perenne L.) induced by heavy metal contaminated soil was evaluated by the biomarkers, including superoxide dismutase and total antioxidant capacity. The comprehensive biomarker response index has a significant exponential correlation with the OP of soil (r​=​0.923, p​<​0.01) in ryegrass. Metabolomics analysis also showed a significant relationship of the metabolic effect level index of amino acids and sugars with OP. Random forest was selected from four machine learning models to screen the metabolites most relevant to OP, and Shapley additive explanations analysis was used to explain the contribution and the influence direction of the features on the model. Based on the selected 20 metabolites, the metabolic pathways most related to OP in plants, including alkaloid synthesis and amino acids metabolism, were identified. Compared to the plant physiological indices, OP is a more stable and faster indicator for the plant risk assessment of heavy metals contaminated soil.

Epichloë endophyte-infected Lolium perenne experienced less oxidative damage when exposed to drought stress

Epichloë endophyte-infected Lolium perenne experienced less oxidative damage when exposed to drought stress

Limitations of the Farquhar–von Caemmerer–Berry Model in Estimating the Maximum Electron Transport Rate: Evidence from Four C3 Species

The study evaluates the accuracy of two FvCB model sub-models (I and II) in estimating the maximum electron transport rate for CO2 assimilation (JA-max) by comparing estimated values with observed maximum electron transport rates (Jf-max) in four C3 species: Triticum aestivum L., Silphium perfoliatum L., Lolium perenne L., and Trifolium pratense L. Significant discrepancies were found between JA-max estimates from sub-model I and observed Jf-max values for T. aestivum, S. perfoliatum, and T. pratense (p &lt; 0.05), with sub-model I overestimating JA-max for T. aestivum. Sub-model II consistently produced higher JA-max estimates than sub-model I. This study highlights limitations in the FvCB sub-models, particularly their tendency to overestimate JA-max when accounting for electron consumption by photorespiration (JO), nitrate reduction (JNit), and the Mehler reaction (JMAP). An alternative empirical model provided more accurate Jf-max estimates, suggesting the need for improved approaches to model photosynthetic electron transport. These findings have important implications for crop yield prediction, ecological modeling, and climate change adaptation strategies, emphasizing the need for more accurate estimation methods in plant physiology research.

Laminaria digitata Extract Improved Leaf Meristem Protection Under Drought and Nitrogen Uptake After Rehydration Through Hormesis-Based Chemical Priming in Lolium perenne.

Drought is among the most damaging stress for plants, impacting crop yield and grassland sustainability. This study aimed to evaluate the biostimulant effect of an algal extract from Laminaria digitata on Lolium perenne cultivated in a growth chamber. Leaves were sprayed at different concentrations 7 days before stopping irrigation. This priming period was followed by fourteen days of drought and ten days of recovery. Algal extract supplied at 2 and 5 L.ha-1 stimulated nitrogen uptake during recovery, while higher doses were deleterious. During drought, algal extract 2 L.ha-1 increased water content in leaves and shoot 0-3 cm housing the leaf meristems. The improvement in water content arose from the smaller decline in leaf relative water content (RWC), suggesting better osmotic adjustment. Cell membrane stability was less impaired during drought and quickly returned to pre-drought levels during recovery, indicating better membrane protection. The higher fructan content may contribute to osmotic adjustment and membrane protection. The results show that algal extract improved leaf meristem protection under drought and N uptake after rehydration through hormesis-based chemical priming. The treatment limited sucrose accumulation during drought, so that sucrose content can be used as an indicator of biostimulation together with RWC and cell membrane stability.

Response of seed germination and seedling growth of perennial ryegrass (Lolium perenne L.) to drought, salinity, and pH in Karst regions

Seed germination and seedling growth are crucial for the successful establishment and reproduction of plants in heterogeneous environments, especially in the ecologically fragile karst regions. Despite the ecological importance of perennial ryegrass (Lolium perenne L.) as a forage resource and its role in mitigating rocky desertification, studies addressing the effects of karst-specific environmental factors on its early growth stages are limited. This study is the first to simulate karst soil conditions to evaluate the impacts of drought (0–0.53 MPa), salinity (0–150 mM), and pH (pH 3–9) on seed germination and seedling growth of perennial ryegrass. The results showed that under different drought stresses, water potentials ranging from 0 to − 0.32 MPa had no significant effect on seed germination. However, water potentials of − 0.06 MPa and − 0.17 MPa significantly promoted root and shoot growth, as well as increased biomass. In the salt stress experiment, CaCl2 concentrations of 5–10 mM favored seed germination; specifically, 5 mM CaCl2 increased the germination rate to 96.5%, and root and shoot lengths exceeded those of the control. pH levels ranging from 3 to 9 had little effect on germination, but extremely acidic conditions (pH 3) significantly inhibited root and shoot elongation. Therefore, optimal growth conditions were determined to be drought stress from 0 to − 0.17 MPa, calcium salt stress from 0 to 25 mM, and a pH of 4 to 9. These findings identify optimal growth conditions for perennial ryegrass, providing a scientific basis for seed cultivation, pasture management, and ecological restoration in karst regions. Our study contributes to the understanding of plant responses to environmental stresses in karst systems and supports sustainable agricultural and conservation practices.

Herbicide mixtures to help slow resistance in three turfgrasses

AbstractSingle active ingredient herbicides were screened for Poa annua control in mostly single replicate trials on 4–12 weeks, and established turf. The species tested were Lolium perenne L. (LP), Lolium arundinaceum (Schreb.) Darbysh. (LA), and a fine fescue blend of Festuca rubra L. and Festuca rubra subsp. commutate. Gaudin. Fl. Helv. (FF). With three exceptions, no significant differences in turf quality could be found between 25 treatments on seedling turf 4–12 weeks old and established turf. Only haloxyfop in fine fescue blend controlled P. annua selectively. Numerous mixtures controlled P. annua selectively in each turfgrass; L. perenne 22, fine fescue blend 17, L. arundinaceum 17. For each species, two consecutive mixtures can be chosen that do not apply the same mode of action twice, for example (LP) 3.5 then 15.4, (LA) 5.2 then 3.15, (FF) 5.2 then 3.15.

Effects of Plantain (Plantago lanceolata L.) Metabolites Aucubin, Acteoside, and Catalpol on Methane Emissions In Vitro.

Plantain (PL) contains plant secondary metabolites (PSM), such as acteoside, aucubin, and catalpol, known for their bioactive properties. While acteoside and aucubin have been linked to reducing nitrogen losses in grazed pastures, their effects on enteric methane (CH4) emissions remain unexplored. Three in vitro batch culture experiments were conducted to assess the effects of PSM on rumen fermentation, using PL pastures with varying PSM concentrations, purified PSM compounds, and/or their combinations added to ryegrass (Lolium perenne, RG), which does not contain these PSM. Aucubin addition to RG extended the time to reach halftime for gas production (GP) and CH4 by 15-20% due to its antimicrobial effects. Acteoside, alone or with aucubin, promoted propionate production, an alternative hydrogen sink, which reduced the acetate to propionate ratio, increased GP by up to 13%, and decreased CH4 proportion in gas by 5-15%. Aucubin reduced ruminal net ammonia (NH3) production by up to 46%, with a similar reduction observed when combined with acteoside. This study highlights the potential of PSM to mitigate CH4 emissions and reduce nitrogen losses from dairy cows, warranting in vivo evaluation of PSM and targeted breeding of PL pastures with increased PSM content.

Enhancing Single-Cell Protein Yield Through Grass-Based Substrates: A Study of Lolium perenne and Kluyveromyces marxianus

This study evaluated Lolium perenne press juice as a sustainable substrate for Single-Cell Protein (SCP) production using Kluyveromyces marxianus. Key fermentation parameters were systematically optimized, including microbial reduction, dilution ratios, temperature, and nutrient supplementation. Pasteurization at 75 °C preserved essential nutrients better than autoclaving, resulting in a 27.8% increase in biomass yield. A 1:2 dilution of press juice enhanced fermentation efficiency, achieving 20.2% higher biomass despite a lower initial sugar content. Cultivation at 30 °C enabled sustained substrate utilization and outperformed 40 °C fermentation, increasing final biomass by 43.4%. Nutrient supplementation with yeast extract, peptone, and glucose led to the highest biomass yield, with a 71% increase compared to unsupplemented juice. Press juice from the tetraploid variety, Explosion, consistently outperformed the diploid Honroso, especially when harvested early, reaching up to 16.62 g·L−1 biomass. Early harvests promoted faster growth, while late harvests exhibited higher biomass yield coefficients due to improved sugar-to-biomass conversion. Compared to a conventional YM medium, fermentation with L. perenne press juice achieved up to a threefold increase in biomass yield. These findings highlight the potential of grass-based substrates for efficient SCP production and demonstrate how agricultural parameters like variety and harvest timing influence both quantity and quality. The approach supports circular bioeconomy strategies by valorising underutilized biomass through microbial fermentation.

Do establishment of multispecies swards affect nitrous oxide and methane emissions and promote soil health?

Do establishment of multispecies swards affect nitrous oxide and methane emissions and promote soil health?

The effect of including plantain (Plantago lanceolata L.) in perennial ryegrass and white clover pastures on milk production and nitrogen excretion of dairy cows throughout the grazing season.

The effect of including plantain (Plantago lanceolata L.) in perennial ryegrass and white clover pastures on milk production and nitrogen excretion of dairy cows throughout the grazing season.

Dry matter intake and production efficiencies of dairy cows rotationally grazing a perennial ryegrass monoculture, a perennial ryegrass-white clover sward, or a multispecies sward.

The objective of this study was to evaluate the effect of sward diversity on individual cow DMI, milk production, and milk production efficiency. In this context, 3 swards were compared: a perennial ryegrass monoculture (Lolium perenne L.; PRG), a PRG with white clover (Trifolium repens L.; PRGWC), and a multispecies sward (MSS) composed of grasses, legumes, and herbs. The experiment followed a randomized block design, encompassing 56.1 ha divided into 20 blocks. Three herds of 49 dairy cows were created, 1 for each sward, and were composed of both pure Holstein-Friesian (HF) and HF crossbred with Jersey (JFX) dairy cows. All the cows were distributed among the 3 treatments according to parity, expected calving date, overall Economic Breeding Index, and milk subindex within each breed. The study monitored pasture production and quality, milk production, DMI, and feed conversion efficiency over a 2-yr period. Results indicated that pregrazing herbage yields and daily herbage allowance were similar across sward types. Daily milk yield (MY) was significantly influenced by sward type, with PRG yielding less than both PRGWC and MSS (13.9, 15.5, and 15.5 kg/cow, respectively). Sward type had a significant effect on DMI, with PRG having the lowest DMI (16.3 kg DM/cow), compared with MSS (18.7 kg DM/cow), which was the highest whereas PRGWC was intermediate (17.5 kg DM/cow). Consequently, feed efficiency was greatest for PRGWC [91 g/unité fourragère lait (UFL) intake], intermediate for the MSS (87 g/UFL), and lowest for the PRG (83 g/UFL). Breed also had a significant effect on MY and composition, with JFX having a lower MY than HF (14.6 and 15.3 kg/cow, respectively) but with increased milk fat (5.31% and 5.72%, respectively) and protein (4.08% and 4.24%, respectively) concentration. Consequently, milk solids (MlS) production was similar for the 2 breeds. The JFX animals were more feed efficient, producing 89 g MlS/UFL intake compared with 84 g for HF. The study highlighted the potential for more diverse swards to improve animal performances in grazing systems while reducing the use of chemical N fertilizer, therefore improving the sustainability of such systems.

Investigating the co-transport and combined toxicity effect of micro-/nano-plastics and PAHs in ryegrass.

Investigating the co-transport and combined toxicity effect of micro-/nano-plastics and PAHs in ryegrass.

Evaluating photosynthetic models and their potency in assessing plant responses to changing oxygen concentrations: a comparative analysis of A n-C a and A n-C i curves in Lolium perenne and Triticum aestivum.

Accurate determination of photosynthetic parameters is essential for understanding how plants respond to environmental changes. In this study, we evaluated the performance of the Farquhar-von Caemmerer-Berry (FvCB) model and introduced a novel model to fit photosynthetic rates against ambient CO2 concentration (A n -C a) and intercellular CO2 concentration (A n -C i) curves for Lolium perenne and Triticum aestivum under 2% and 21% O2 conditions. We observed significant discrepancies in the FvCB model's fitting capacity for A n -C a and A n -C a curves across different oxygen regimes, particularly in estimates of key parameters such as the maximum carboxylation rate (V cmax), the day respiratory rate (R day), and the maximum electron transport rate for carbon assimilation (J A-max). Notably, under 2% and 21% O2 conditions, the values of V cmax and R day derived from A n -C a curves using the FvCB model were 46.98%, 44.37%, 46.63%, and 37.66% lower than those from A n -C i curves for L. perenne, and 47.10%, 44.30%, 47.03%, and 37.36% lower for T. aestivum, respectively. These results highlight that the FvCB model yields significantly different V cmax and R day values when fitting A n -C a versus A n -C i curves for these two C3 plants. In contrast, the novel model demonstrated superior fitting capabilities for both A n -C a and A n -C i curves under 2% and 21% O2 conditions, achieving high determination coefficients (R 2≥ 0.989). Key parameters such as the maximum net photosynthetic rate (A max) and the CO2 compensation point (Γ) in the presence of R day, showed no significant differences across oxygen concentrations. However, the apparent photorespiratory rate (R pa0) and photorespiratory rate (R p0) derived from A n -C i curves consistently exceeded those from A n -C a curves for both plant species. Furthermore, R pa0 values derived from A n -C a curves closely matched observed values, suggesting that A n -C a curves more accurately reflect the physiological state of plants, particularly for estimating photorespiratory rates. This study underscores the importance of selecting appropriate CO2-response curves to investigate plant photosynthesis and photorespiration under diverse environmental conditions, thereby ensuring a more accurate understanding of plant responses to changing environments.

The Effects of a Small Dose of Tannin Supplementation on In Vitro Fermentation Characteristics of Different Forages.

Pastoral systems in New Zealand are under societal pressure due to their increasing negative environmental impact in terms of greenhouse gas emissions. This study was conducted to investigate the effects of supplementing a mixture containing hydrolysable and condensed tannins on the in vitro fermentation characteristics and gas production of three different forages, Lolium perenne, Medicago sativa, and Plantago lanceolata. Three fermentation runs of 48 h were conducted using the ANKOM gas production technique, with each pertaining to a particular forage with or without (control) tannin. Tannins were added to the fermentable substrate (i.e., forage) at a level of 0.3%. For each run, rumen fluid was collected from two fistulated Holstein Friesian × Jersey cows. The ANKOM RF gas production modules were used to monitor gas pressure and temperature every 5 min. At the end of each run, the pH of the fluid was measured, gas vials were taken for methane (CH4) measurements and liquor samples were taken to measure volatile fatty acids (VFA) and NH3 concentrations. The addition of tannins reduced the fractional rate of gas production for alfalfa (p ≤ 0.04) but increased it for ryegrass and plantain. There was a tendency for reduced gas production for ryegrass when tannins were added (p = 0.10). There was also a tendency for CH4 production to reduce (p < 0.10) and N2O to increase (p = 0.10) when tannins were added. Iso-butyrate tended to be lower for ryegrass control than to ryegrass with tannins (p = 0.08). Valerate concentration was lower for plantain control than to plantain with tannins. No effects were detected for gas composition (p > 0.05) or VFA concentrations (p > 0.05) when fermenting alfalfa. Under the condition of this study, these results may suggest that low-level tannin addition to the diet may affect rumen-fermentation pattern with a potential reduction of CH4 production in Lolium perenne-based diets. Further research is required on the effect of low levels of tannin supplementation under ex vitro and in vivo conditions as tannin supplementation effects might be substrate-dependent.

First report of blast disease caused by Pyricularia oryzae on creeping bentgrass in Japan

AbstractIn August 2008, a patch disease of creeping bentgrass (Agrostis stolonifera L.) was discovered at golf courses in Shizuoka and Kyoto, Japan. The disease occurred in dark brown patches that ranged from several to 10 cm in diameter. Affected plant individuals within the patch exhibited dark brown leaf blight and withering. Pyricularia fungi, which cause blast disease in grasses, were observed, and two strains were obtained from the affected plants. Based on the morphological characteristics and the nucleotide sequences of internal transcribed spacer regions with 5.8S ribosomal DNA and the β‐tubulin gene, they were identified as Pyricularia oryzae. For pathogenicity tests, the strain was grown in a soil‐bran medium and inoculated to creeping bentgrass plants grown in pots. As a result, many spindle‐shaped lesions were formed on the leaves, which later showed leaf blight and plant withering. Inoculation was made in the same manner as for other grass species, and the fungus showed pathogenicity on colonial bentgrass, perennial ryegrass, tall fescue, and Kentucky bluegrass. In conclusion, this is the first report of blast disease of creeping bentgrass by P. oryzae in the world, which has a wide host range in gramineous plants.

Exploring the phytostabilization potential of ryegrass (Lolium perenne L.) upon synergistic application of Cd-tolerant Pseudomonas fluorescens and organic amendments

Soil Cd contamination limits plant productivity by affecting their key functions and reducing yields. In-situ immobilization of heavy metals (HMs) can achieve ‘green’ and ‘sustainable’ ways of HM remediation owing to its lower life cycle environmental footprints. This study explored the effects of Cd-resistant P. fluorescens and OAs such as rice straw, wheat straw and cow dung (1% w/w) on the Cd tolerance of ryegrass under Cd contamination (2.2 mg kg−1). In our findings, Cd exposure reduced plant height (22%), root length (38%), chlorophyll ‘a’ and ‘b’ (36 and 38%), and relative water content (32%) in uninoculated plants. However, combined use of P. fluorescens and OAs mitigated these effects by immobilizing Cd in soil, with a 56% increase in residual Cd and higher Cd retention in roots and shoots (77 and 87%). Co-application enhanced plant height (96%), root length (158%), chlorophyll content (90 and 98%), relative water content (168%), flavonoids and phenols (151 and 68%) and NPK uptake (104, 73 and 71%) as compared to uninoculated control. Integration of P. fluorescens and OAs not only reduced Cd uptake but also improved growth and yield. Thus, this approach mitigates Cd stress in ryegrass, improving growth and physiology by reducing Cd uptake.

First report of dollar spot caused by Clarireedia jacksonii on annual bluegrass in western Oregon and pathogenicity testing of multiple turfgrasses

Dollar spot of annual bluegrass (Poa annua), caused by Clarireedia jacksonii has never been formally reported in Oregon. This pathogen is one of the most important turfgrass diseases of cool-season grasses worldwide. In 2023, C. jacksonii was detected on an annual bluegrass putting green in Corvallis, Oregon. This report details the identification efforts, and pathogenicity testing of the recovered isolate on annual bluegrass, creeping bentgrass, perennial ryegrass, and tall fescue. The confirmation of C. jacksonii in Oregon may have management implications for golf course superintendents of the state.

RD29A-IPT expression enhances drought tolerance in transgenic perennial ryegrass

Abstract Genetic improvement and the identification of drought-tolerant cultivars are crucial in perennial ryegrass (Lolium perenne L.) turfgrass to enhance germplasm reserves for molecular breeding and the development of sustainable landscapes in arid and semi-arid green spaces. Cytokinins (CKs) are plant hormones that regulate various physiological processes, including cell division, shoot growth, and leaf senescence, and also are known to regulate plant responses to drought stress. This study aimed to enhance drought tolerance in perennial ryegrass cultivars by utilizing the drought-inducible RD29A promoter to drive the expression of the IPT gene, which boosts cytokinin levels. The research also compared the performance of these transgenic plants with wild-type (WT) plants and local perennial ryegrass accessions under varying irrigation conditions. Results showed that certain transgenic plants and local accessions displayed higher drought tolerance based on turf quality, physiological, and biochemical characteristics. The expression of the IPT gene was confirmed in transgenic plants exposed to drought stress. Transgenic lines including GM24, GM12, GC8, GC6, NC12, NC14, NS14, and GC3 exhibited increased drought tolerance, maintaining higher levels of cytokinins in the leaves, improving water content, photosynthetic rate, and antioxidant activity while reducing damage indicators. Catalase and superoxide dismutase activities were more influential than peroxidase in drought adaptation and recovery. The efficiency of the RD29A promoter and the use of the UBQ10 intron in the IPT gene construct affected gene expression. Moreover, the significant genotypic variation among local accessions indicates opportunities for improving drought tolerance through targeted breeding in sensitive and moderately tolerant genotypes. Further research is recommended to investigate hormonal balance and osmoregulation in transgenic and wild-type plants under multiple stresses. Additionally, identifying candidate genes involved in drought tolerance, particularly in local ryegrass accessions, should be a focus for future studies.

Characterization of Cd and As accumulation and subcellular distribution in different varieties of perennial ryegrasses

BackgroundThe distribution, accumulation, and toxicological effects of two perennial ryegrass (Lolium perenne L.) varieties under combined cadmium (Cd)-arsenic (As) stress are worth exploring. Two varieties, ʻNicaraguaʼ (high-Cd/As-accumulating, DPB) and ʻVenusʼ (low-Cd/As-accumulating, WNS), were selected as experimental materials for pot trials. Subcellular fractionation, ultrastructural changes, and key transporter proteins cation exchanger (CAX), heavy metal ATPase (HMA), natural resistance-associated macrophage protein (NRAMP), and phosphate transporter (PHT) were analyzed under combined Cd-As stress.Results(1) The translocation factors of perennial ryegrass for Cd and As were < 1. Cd and As were mainly distributed in the cell wall and the soluble fractions. The total percentage of Cd and As in the cell wall and the soluble fractions of DPB variety was 92.53 and 91.29%, respectively. (2) Cd and As stress on the cellular ultrastructure of two perennial ryegrasses resulted in plasmodesmata separation of leaf cells, swelling of chloroplasts, large numbers of osmiophilic granules, and thickening of root cell walls. Cell wall thickening was more pronounced in the low-accumulating variety. (3) The highest increase in HMA activity, which increased by 79.08% over the non-Cd/As treatment, was observed in the roots of DPB under Cd and As stress. Cd and As stress induced HMA activity (P < 0.01) in the highly accumulating variety DPB, and positively promoted Cd translocation and storage in the soluble fraction (vacuole).ConclusionsLow Cd accumulation variety mainly resisted heavy metal through bound more Cd and As to cell wall resulting in cell wall thicken. High-Cd accumulation variety DPB stored Cd and As in the soluble fraction (vacuole ), and enhanced activity of the transporter protein HMA. This study elucidates the relationship and role of key transporter proteins of high/low accumulating perennial ryegrass with cellular Cd/As detoxification modes such as cell wall barrier defence and vesicle compartmentalisation, and provides a theoretical basis for differential detoxification strategies for species with different accumulating characteristics.Graphical