Search

We conducted a four-year cutting experiment on herbage yield, with three years focused on testing the effect of perennial ryegrass (PR) cultivars 'Elena DS', 'Raminta', and 'Verseka', along with a cultivar mixture and compositions with white clover (WC) and red clover (RC) diversity, on crude protein (CP), modified acid detergent fibre (MADF), neutral detergent fibre (NDF), water-soluble carbohydrates (WSC), and dry matter digestibility (DMD) content. PR cultivars and cultivar mixtures were sown alone (N150), and the PR 'Elena DS' and PR cultivar mixtures were also sown with each WC, or WC and RC (N0). The average four-year herbage productivity was the lowest in PR 'Elena DS' the and cultivar mixture/WC, followed by all of the pure PR swards, and the highest in PR 'Elena DS' and the cultivar mixture/WC+RC; however, the PR 'Elena DS'/WC+RC mixture had the highest legume proportion and CP content. There was less NDF but also WSC in swards with legumes, but higher CP content than in pure PR swards; however, the highest CP content was in mixtures with RC. Among the grasses, PR 'Verseka' had lower NDF contents and a higher WSC than PR 'Elena DS', 'Raminta', and the cultivar mixture. Overall, this study revealed significant differences in the productivity of PR cultivars with a potential yield difference of up to 1.7 t ha−1. [ABSTRACT FROM AUTHOR]

Rhizosphere microorganisms are crucial for enhancing plant stress resistance. Current studies have shown that Arbuscular mycorrhizal fungi (AMF) can facilitate vegetation recovery in heavy metal-contaminated soils through interactions with rhizosphere microbiota. However, the mechanisms by which AMF influences rhizosphere microbiota and plant growth under cadmium (Cd) stress remain unclear. In this study, Lolium perenne L. was inoculated with AMF (Rhizophagus irregularis) and grown in soils supplemented with Cd (0 mg kg−1, Cd0; 100 mg kg−1, Cd100). Plant biomass, antioxidant enzyme activities, peroxide content, Cd uptake, and rhizosphere bacterial community composition were evaluated. AMF inoculation reduced Cd influx in aboveground tissues, enhanced nutrient availability in the rhizosphere, and mitigated Cd biotoxicity. Additionally, AMF inoculation improved the scavenging efficiency of reactive oxygen species and alleviated oxidative stress in L. perenne, thereby mitigating biomass reduction. Moreover, AMF treatment increased leaf and root biomass by 342.94% and 41.31%, respectively. Furthermore, under the same Cd concentration, AMF inoculation increased bacterial diversity (as measured by the Shannon index) and reduced bacterial enrichment (as indicated by the ACE index). AMF promoted the enrichment of certain bacterial genera (e.g., Proteobacteria and Actinobacteria) in the Cd100 group. These findings suggest that AMF regulated the composition of the rhizosphere bacterial community and promoted the growth of potentially beneficial microorganisms, thereby enhancing the resistance of L. perenne to Cd stress. Cd contamination in soil severely limits plant growth and threatens ecosystem stability, highlighting the need to understand how AMF and rhizosphere microbes can enhance Cd tolerance in L. perenne. Therefore, inoculating plants with AMF is a promising strategy for enhancing their adaptability to Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

Lawn performs best with minimum inputs when grown in mixtures using more than a single grass specie. A study was conducted under open field conditions to evaluate the performance of four lawn grass species as mono-stand and in mixtures under mid-hill conditions at the Experimental Farm of the Department of Floriculture and Landscape Architecture, Dr Yashwant Singh Parmar University of Horticulture and Forestry, Nauni, Solan (H.P.) during March, 2020 to March, 2021. The experiment was laid out in a randomized block design with twelve treatments and three replications. Data was recorded at fortnight intervals for total weed count, chlorophyll content, number of mowing, and overall presentability just after turf establishment. It was observed that all turf grass mixtures, performed better than the monostands, during the entire course of the study. Turf grass mixture (50% 'Agrostis stolonifera' + 20% 'Festuca rubra' + 20% 'Lolium perenne' + 10% 'Cynodon dactylon)' required least number of mowing and was presentable throughout the year attaining highest presentability score of 22.98. [ABSTRACT FROM AUTHOR]

In the framework of the evaluation, valorization and conservation of plant genetic resources, six natural populations belonging to two species of forage grasses, perennial ryegrass (Lolium perenne L.) and annual ryegrass (Lolium rigidum Gaud.) collected in different agro-ecological regions of Algeria, were used to assess the effects of four NaCl and Na2SO4 concentrations (0, 50, 100, 150 mM) on germination parameters: germination percentage (GP), germination rate index (GRI), mean germination time (MGT), salt tolerance index (STI), seedling vigor index (SVI), shoot and root length. Seeds were germinated in an incubator at 20°C for 12 days in a completely randomized design with five replicates. The results revealed significant effects of NaCl and Na2SO4, populations and their interactions on germination parameters. Salinity reduced GP, STI, VI, GRI, shoot and root length, but increased MGT, in contrast to control experiment (0 mM). An important decrease was globally observed in the two species in all parameters with the lowest values at 100 and 150 mM except MGT. Compared to NaCl, the decrease was more important under Na2SO4. Population LP1 of L. perenne and the three populations of L. rigidum in the control and in the two salts showed the highest means of GP, GRI and SVI. Populations LR3 of L. rigidum (arid area) and LP3 of L. perenne (sub humid area) were the most sensitive at 150 mM. The shorter MGT was obtained in population LP1 of L. perenne which seems to be more salt-tolerant toward the two salts than the annual L. rigidum. [ABSTRACT FROM AUTHOR]

The study was conducted in the experimental field of the Research Institute of Mountain Stockbreeding and Agriculture of Troyan, with the aim of determining the correlation and regression dependences between some basic chemical indicators and the energy nutritional value of perennial ryegrass and legume fodder crop grown in monoculture and mixed grasslands. Data analysis shows that the amount of crude protein has a statistically significant impact on the in vitro digestibility of dry matter (r = 0.82) and the number of feed units (r = 0.88 - for FUM and r = 0.87 - for FUG). The yield of fresh matter was positively correlated with the dry matter yield (r = 0.83), the amount of NDF (r = 0.74) and hemicellulose (r = 0.80). The high correlation and dependence between fiber components of perennial grasses and legume fodder crops gives a clear assessment for forage quality. The coefficients of determination between structural fiber components and crude fiber concentration ranged from R² = 0.5176 to R² = 0.9186, with very well-proven statistical significance of the equations. [ABSTRACT FROM AUTHOR]

Water‐use efficiency (WUE) is an under‐researched but very important drought tolerance trait in forage breeding. This research estimated quantitative genetic parameters of morpho‐physiological traits linked to agronomic water‐use efficiency (WUEA) and its proxy measures based on δ13C (WUEi) or gas exchange (evapotranspiration, WUEAET, or stomatal conductance WUEASC) of genotypes from half‐sib families of Lolium perenne L. (PRG) in a simulated summer drought cycle. Principal component analysis (PCA) of trait data distinguished a group of PRG genotypes where high WUEA and dry matter yield was associated with deep rooting, leaf hydration at more negative leaf osmotic and water potential, and reduced soil moisture depletion. Plants with this trait association sustained net assimilation and postdefoliation regrowth in drought. However, WUEi, WUEASC, and WUEAET were poorly correlated with most traits of interest at p <.05. Another PCA revealed a weak association between WUEA and its proxy measures under conditions tested. Quantitative genetic parameters including high estimates of narrow‐sense heritability (hn2>0.7;p<.05) of WUEA and related traits emphasized the genetic potential of the key trait combination for selecting PRG for improved drought tolerance. Research findings highlight the relative importance of WUEA and its proxy measures in the broad definition of PRG drought tolerance for breeding purposes. [ABSTRACT FROM AUTHOR]

The experiment was conducted at the Research Institute of Mountain Stockbreeding and Agriculture, Troyan (Bulgaria) with the aim of establishing the impact of the fertilizers Nano Sulfur and Panamin Agro on the height, productivity and composition of sown grass stand from perennial ryegrass (Lolium perenne L.). The perennial ryegrass plants have proven to form the highest grass stand with the application of Panamin Agro biofertilizer (250 g/da). The harvested biomass registered 4.05 cm (at P <0.05) higher values of the trait compared to the control (67.18 cm). The highest average yield of fresh matter was registered in the grass stand of Lolium perenne L. treated with Panamin Agro - 250 g/da. The values of the trait significantly exceeded the unfertilized control by 16.87% (P <0.05). No significant difference was proven in the amount of dry matter was found between the fertilized variants and the untreated control of perennial ryegrass. Lolium perenne L. occupied the highest relative share in the variants treated with Nano Sulfur (200 ml/da) and Panamin Agro (250 g/da). The percentage share of the grass crop was respectively 89.94% and 88.71% (in the control variant - 79.95%). The specified variants had the lowest degree of weed infestation. [ABSTRACT FROM AUTHOR]

The contamination of soil and water by metals such as mercury (Hg) and cadmium (Cd) has been increasing in recent years, because of anthropogenic activities such as mining and agriculture, respectively. In this work, the changes in the rhizosphere microbiome of Lolium perenne L. during the phytoremediation of soils contaminated with Hg and Cd were evaluated. For this, two soil types were sampled, one inoculated with mycorrhizae and one without. The soils were contaminated with Hg and Cd, and L. perenne seeds were sown and harvested after 30 days. To assess changes in the microbiome, DNA isolation tests were performed, for which samples were subjected to two-step PCR amplification with specific 16S rDNA V3-V4 primers (337F and 805R). With mycorrhizae, changes had been found in the absorption processes of metals and a new distribution. While with respect to microorganisms, families such as the Enterobacteriaceae have been shown to have biosorption and efflux effects on metals such as Hg and Cd. Mycorrhizae then improve the efficiency of removal and allow the plant to better distribute the absorbed concentrations. Overall, L. perenne is a species with a high potential for phytoremediation of Cd- and Hg-contaminated soils in the tropics. Inoculation with mycorrhizae modifies the phytoremediation mechanisms of the plant and the composition of microorganisms in the rhizosphere. Mycorrhizal inoculation and changes in the microbiome were associated with increased plant tolerance to Cd and Hg. Microorganism-assisted phytoremediation is an appropriate alternative for L. perenne. [ABSTRACT FROM AUTHOR]

In the period 2020-2022, in the experimental field of RIMSA – Troyan, a comparative test of perennial ryegrass (Lolium perenne L.) varieties was conducted in the direction of forage productivity. According to the results, the genotypic factor, respectively the choice of variety, has a significant impact on the productivity of independent cultivation of pasture ryegrass in the mountainous conditions of Northern Bulgaria. The highest dry matter yield, on average for the period, was registered for Nui (1161 kg/da) and Tetramis (1146 kg/da). Maximum height and lowest phenotypic variability by year were formed by the cultivars Tetramis (69.28 cm) and Nui (67.93 cm). The Bulgarian cultivarsultivar, such as the diploid standard c Harmoniya and the tetraploid Tetramis and Tetrani had equal productivity for a medium-long period of use. The grass stands of the Nira and Bokser cultivars were proven to have a lower yield of fresh and dry matter compared to the standard (Harmoniya). [ABSTRACT FROM AUTHOR]

The purpose of the experiment is to determine the composition and energy value of fodder from monoculture and mixed grass stands of perennial ryegrass with legume fodder crops under mountain conditions. It was found that the concentration of the fiber components of the cell walls in the monoculture grass stands of perennial ryegrass was significantly higher compared to the mixed ones, which affected the forage mass digestibility. The highest dry matter digestibility was registered in the biomass of Lolium perenne L. + Trifolium repens L. mixture (642.54 g kg-1 DM) followed by Lolium perenne L. + Lotus corniculatus L. (636.28 g kg-1 DM) and Lolium perenne L. + Trifolium pratense L. (622.18 g kg-1 DM). The monoculture grass stands with red clover had the highest content of neutral detergent fibers (418.03 g kg-1 DM), whereas the bird's-foot-trefoil biomass had the highest concentration of acid detergent fibers (291.98 g kg-1 DM), acid-detergent lignin (70.72 g kg-1 DM) and cellulose (221.27 g kg-1 DM). The forage mass of pasture ryegrass registered lower values for all the investigated parameters compared to its mixtures with leguminous forage crops. The highest caloric content is the harvested grass stands of Lolium perenne L. with Lotus corniculatus L. (17.48 MJ/kg DM). Biomass also has the highest average value of energy useful for the normal course of physiological needs in the animal organism (7.45 MJ/kg DM), as well as in terms of the number of feed units for milk (0.68 in kg DM) and growth (0.62 in kg DM). [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne L.) is an important turfgrass and gramineous forage widely grown in temperate regions around the world. However, its perennial nature leads to the inevitable exposure of perennial ryegrass to various environmental stresses on a seasonal basis and from year to year. Like other plants, perennial ryegrass has evolved sophisticated mechanisms to make appropriate adjustments in growth and development in order to adapt to the stress environment at both the physiological and molecular levels. A thorough understanding of the mechanisms of perennial ryegrass response to abiotic stresses is crucial for obtaining superior stress-tolerant varieties through molecular breeding. Over the past decades, studies of perennial ryegrass at the molecular and genetic levels have revealed a lot of useful information to understand the mechanisms of perennial ryegrass adaptation to an adverse environment. Unfortunately, molecular mechanisms by which perennial ryegrass adapts to abiotic stresses have not been reviewed thus far. In this review, we summarize the recent works on the genetic and molecular mechanisms of perennial ryegrass response to the major abiotic stresses (i.e., drought, salinity, and extreme temperatures) and discuss new directions for future studies. Such knowledge will provide valuable information for molecular breeding in perennial ryegrass to improve stress resistance and promote the sustainability of agriculture and the environment. [ABSTRACT FROM AUTHOR]

Understanding the differences in cool-season turfgrass responses to shade is critical for future turfgrass management and breeding for improved shade tolerance. The purpose of this study was to evaluate the shade-tolerance mechanisms of two cool-season turfgrass species in terms of turf performance, growth, and physiological characteristics. Two turfgrass species, namely, 'SupraNova' (Poa. supina Schrad.) and 'Lark' (Lolium perenne L.), were subjected to 0 (CK, unshaded), 35% (LS), 70% (MS), and 92% (HS) shade, respectively. Compared with 'Lark', 'SupraNova' showed better turf quality (TQ) and turf color intensity (TCI) under shade. The total length and surface area of the roots of 'Lark' gradually decreased as the shade increased, while those of 'SupraNova' increased and then decreased with increasing shade. The chlorophyll fluorescence photochemical quenching coefficient (qP), electron transport rate (ETR), and maximum quantum yield of primary photosystem II (PSII) photochemistry (Fv/Fm) decreased significantly under HS; however, these decreases were more significant in 'Lark' than in 'SupraNova'. The leaf reflectance of the two turfgrasses under shade was lower than that under CK, but the leaf reflectance of 'Lark' was higher than that of 'SupraNova' in the visible light band. The normalized difference vegetation index (NDVI) of the two grasses first decreased and then increased. The NDVI of 'Lark' under shade was slightly higher than that under CK. 'SupraNova' showed strong tolerance on the basis of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion (O2·−), and ascorbic acid (AsA) contents and superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activity. The MDA, H2O2, O2·−, and AsA contents and SOD, POD, and CAT activity (which represent indicators) changed the most under MS. Taken together, the results indicated that the adaptability of 'SupraNova' to shade was better than that of 'Lark'. [ABSTRACT FROM AUTHOR]

Methyl jasmonate (MeJA) plays a role in improving plant stress tolerance. The molecular mechanisms associated with heat tolerance mediated by MeJA are not fully understood in perennial grass species. The study was designed to explore transcriptomic mechanisms underlying heat tolerance by exogenous MeJA in perennial ryegrass (Lolium perenne L.) using RNA-seq. Transcriptomic profiling was performed on plants under normal temperature (CK), high temperature for 12 h (H), MeJA pretreatment (T), MeJA pretreatment + H (T-H), respectively. The analysis of differentially expressed genes (DEGs) showed that H resulted in the most DEGs and T had the least, compared with CK. Among them, the DEGs related to the response to oxygen-containing compound was higher in CKvsH, while many genes related to photosynthetic system were down-regulated. The DEGs related to plastid components was higher in CKvsT. GO and KEGG analysis showed that exogenous application of MeJA enriched photosynthesis related pathways under heat stress. Exogenous MeJA significantly increased the expression of genes involved in chlorophyll (Chl) biosynthesis and antioxidant metabolism, and decreased the expression of Chl degradation genes, as well as the expression of heat shock transcription factor - heat shock protein (HSF-HSP) network under heat stress. The results indicated that exogenous application of MeJA improved the heat tolerance of perennial ryegrass by mediating expression of genes in different pathways, such as Chl biosynthesis and degradation, antioxidant enzyme system, HSF-HSP network and JAs biosynthesis. [ABSTRACT FROM AUTHOR]

Various adaptive mechanisms can ensure that seedlings are established at the most favourable time and place. These mechanisms include seed dormancy i.e., incapacity to germinate in any environment without a specific environmental trigger and inhibition i.e., incapacity to germinate in an unfavourable environment (water availability, temperature: thermoinhibition and light). The objective of this research was to study in the temperate range for germination of forage and turf grass species perennial ryegrass, if the thermal requirements for germination are under genetic controlled and could be selectively bred. Two divergent selections of three cycles were realized on a natural population: one to select for the capacity to germinate at 10°C vs. the impossibility to germinate at 10°C, and one to select for the capacity to germinate at 32°C vs. the impossibility to germinate at 32°C. Seeds of all the lots obtained from the two divergent selections were then germinated at constant temperatures from 5 to 35°C to evaluate their germination ability. Concerning the positive selection, the first cycle of positive selection at 10°C was highly efficient with a very strong increase in the germination percentage. However, afterward no selection effect was observed during the next two cycles of positive selection. By contrast, the positive selection at 32°C was efficient during all cycles with a linear increase of the percentage of germination at 32°C. Concerning the negative selection, we observed only a large positive effect of the first cycle of selection at 10°C. These findings demonstrate that seed thermoinhibition at 10 and 32°C observed in a natural population of perennial ryegrass has a genetic basis and a single recessive gene seems to be involved at 10°C. [ABSTRACT FROM AUTHOR]

Perennial ryegrass is an important forage crop in dairy farming, either for grazing or haying purposes. To further optimise the forage use, this study focused on understanding forage digestibility in the two most important cuts of perennial ryegrass, the spring cut at heading and the autumn cut. In a highly diverse collection of 592 Lolium perenne genotypes, the organic matter digestibility (OMD) and underlying traits such as cell wall digestibility (NDFD) and cell wall components (cellulose, hemicellulose, and lignin) were investigated for 2 years. A high genotype × season interaction was found for OMD and NDFD, indicating differences in genetic control of these forage quality traits in spring versus autumn. OMD could be explained by both the quantity of cell wall content (NDF) and the quality of the cell wall content (NDFD). The variability in NDFD in spring was mainly explained by differences in hemicellulose. A 1% increase of the hemicellulose content in the cell wall (HC.NDF) resulted in an increase of 0.81% of NDFD. In autumn, it was mainly explained by the lignin content in the cell wall (ADL.NDF). A 0.1% decrease of ADL.NDF resulted in an increase of 0.41% of NDFD. The seasonal traits were highly heritable and showed a higher variation in autumn versus spring, indicating the potential to select for forage quality in the autumn cut. In a candidate gene association mapping approach, in which 503 genes involved in cell wall biogenesis, plant architecture, and phytohormone biosynthesis and signalling, identified significant quantitative trait loci (QTLs) which could explain from 29 to 52% of the phenotypic variance in the forage quality traits OMD and NDFD, with small effects of each marker taken individually (ranging from 1 to 7%). No identical QTLs were identified between seasons, but within a season, some QTLs were in common between digestibility traits and cell wall composition traits confirming the importance of hemicellulose concentration for spring digestibility and lignin concentration in NDF for autumn digestibility. [ABSTRACT FROM AUTHOR]

Agricultural grass cultivars bred for increased forage yield commonly have extensive root systems. As roots are an important input of organic matter into the soil, it follows that such cultivars could lead to important increases in soil organic carbon (SOC), but this, and the mechanisms involved, are poorly understood with little empirical field evidence. We assessed the effect of two cultivars, Lolium perenne L. cv. "AberMagic" and L. perenne L. × Festuca pratensis Huds. cv. "Prior", in comparison with mixed‐species permanent pasture ("Pasture") in a field experiment on temperate alluvial soil in the southwest UK. Root and SOC stocks, and specific plant‐derived lipids as mechanistic biomarkers for shoot and root inputs of C, were measured on intact 1‐m volumetric soil cores collected on four dates in 2013–2015. Total grass yields were greater for both grass cultivars (40–43 Mg ha−1) than Pasture (39 Mg ha−1), and by 2015 root stocks in the upper 0.1 m were significantly greater by more than 4.7 Mg ha−1. At 0.1–0.3 m depth, SOC stocks (per 0.1‐m depth) were significantly greater under the two grass cultivars (24–50 Mg ha−1) compared to Pasture (18–32 Mg ha−1). In the full 1‐m profile, mean SOC stocks were 137, 133 and 110 Mg ha−1 for AberMagic, Prior and Pasture, respectively, matching root biomass distribution. Odd‐chain n‐alkane concentrations were significantly greater for shoots than roots (274 vs. 64 mg kg−1, respectively), and roots had significantly greater concentrations than shoots of even‐chain hydroxy fatty acids (1829 vs. 305 mg kg−1, respectively) and diacids (317 vs. 93 mg kg−1, respectively). This confirmed lipids as candidate biomarkers for distinguishing shoot and root inputs into the soil, with roots being the dominant source of SOC. Based on the observations of increased forage yield and SOC stock, high‐yielding forage grass cultivars can contribute to future strategies for climate‐smart agriculture in grassland‐dominated temperate regions. Highlights: Selected root traits for increased depth, density and diameter may increase SOC in grassland.The effect of two high‐yielding forage grass cultivars were assessed in a field trial.Fast‐growing, high‐yielding cultivars enhanced root and SOC stocks compared to typical pasture.Lipid biomarkers confirmed that root inputs were the predominant C input to soil. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Remediation using plant-microbe interactions is an efficient and cost-effective technique. However, few studies have reported their effects in phosphate mining wastelands. In this study, two native phosphate-solubilizing microorganisms (PSM) (Trichoderma asperellum LZ1 and Serratia sp. LX2) and two native plants (Lolium perenne L. and Lactuca versicolor) were used to remediate excess phosphorus (P) contamination in phosphate mining wasteland soil. In pot experiments, PSM was found to increase P availability by reducing soil pH. The inoculation of strain LZ1 and LX2 significantly increased the total biomass of L. perenne L. by 41.73%, 6.27%, and 49.26%, respectively. Similarly, L. versicolor biomass also increased by 17.51%, 11.67%, and 41.16%, respectively. In addition, the root, shoot length, and chlorophyll content of L. perenne L. and L. versicolor were also significantly higher than those of the treatments inoculated without PSM. In PSM-inoculated soils, the P accumulation in L. perenne L. and L. versicolor was 11.71 and 5.54 mg/pot, respectively. The findings in this study showed that T. asperellum LZ1 and Serratia sp. LX2 could effectively promote the growth of L. perenne L. and L. versicolor, and increase the P accumulation in plants, which would be beneficial to the phytoremediation of excess P contamination in phosphate mining wasteland. [ABSTRACT FROM AUTHOR]

The sustainability of warm-season turfgrass species in winter dormancy is a major concern in Mediterranean ecology. The concept of overseed a lawn has been still new for many developing countries such as Turkey as part of a regular maintenance. Therefore, a 2-year study was conducted at the experimental fields of Ege University, Izmir/Turkey during 2014-2016 years to compare the effects of four different overseeding times (September 15, September 30, October 15 and October 30) on four warm season turfgrass species (Cynodon dactylon cv. SR9554, Cynodon dactylon × Cynodon transvaalensis cv. Tifway-419, Paspalum vaginatum cv. Sea Spray and Zoysia japonica cv. Zenith) by measuring visual turf quality (1-9 score) and some related characteristics as texture (mm), cover (1-9 score), weed infestation (1-9 score) and colour (1-9 score). '50% cv. Troya+50% cv. Esquire' perennial ryegrass (Lolium perenne L.) mixture was used for overseeding in trial. According to results, visual turf quality performance of 6.0 scores and above were obtained from all treatments. We concluded that October 15 should be most suitable time for overseeding applications. Additionally, L. perenne L. can be practiced successfully in Mediterranean region in order to eliminate the concerns of warm-season turfgrasses in the winter dormancy period observed in cold temperatures. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is the most cultivated cool-season grass worldwide with crucial roles in carbon fixation, turfgrass applications, and fodder for livestock. Lolium perenne forms a mutualism with the strictly vertically transmitted fungal endophyte, Epichloë festucae var lolii. The fungus produces alkaloids that protect the grass from herbivory, as well as conferring protection from drought and nutrient stress. The rising concentration of atmospheric CO2, a proximate cause of climatic change, is known to have many direct and indirect effects on plant growth. There is keen interest in how the nature of this plant--fungal interaction will change with climate change. Lolium perenne is an obligately outcrossing species, meaning that the genetic profile of the host is constantly being reshuffled. Meanwhile, the fungus is asexual implying both a relatively constant genetic profile and the potential for incompatible grass--fungus pairings. In this study, we used a single cultivar, "Alto", of L. perenne. Each plant was infected with one of four strains of the endophyte: AR1, AR37, NEA2, and Lp19 (the "common strain"). We outcrossed the Alto mothers with pollen from a number of individuals from different ryegrass cultivars to create more genetic diversity in the hosts. We collected seed such that we had replicate maternal half-sib families. Seed from each family was randomly allocated into the two levels of the CO2 treatment, 400 and 800 ppm. Elevated CO2 resulted in an c. 18% increase in plant biomass. AR37 produced higher fungal concentrations than other strains; NEA2 produced the lowest fungal concentrations. We did not find evidence of genetic incompatibility between the host plants and the fungal strains. We conducted untargeted metabolomics and quantitative proteomics to investigate the grass-fungus interactions between and within family and treatment groups. We identified a number of changes in both the proteome and metabalome. Taken together, our data set provides new understanding into the intricacy of the interaction between endophyte and host from multiple molecular levels and suggests opportunity to promote plant robustness and survivability in rising CO2 environmental conditions through application of bioprotective epichloid strains. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the grazing efficiency of 30 perennial ryegrass varieties, differing in ploidy and heading date. Plots were grazed by lactating dairy cows and managed under a rotational grazing system with 19 grazing events occurring over two years. Pre‐grazing and post‐grazing compressed sward heights were measured with a rising plate meter. A mixed model was used to predict the post‐grazing sward height of each variety based on year, grazing event, block and pre‐grazing sward height. Residual grazed height (RGH) was derived as the difference between the actual and predicted post‐grazing sward height and was used as the measure of grazing efficiency. Negative RGH values indicated that the actual herbage removed was greater than that predicted and so indicated a superior grazing efficiency. Varieties differed in their level of grazing efficiency (p <.001), with RGH values ranging from −0.38 to +0.34 cm. Tetraploid varieties exhibited significantly greater grazing efficiency performance than diploids (p <.001), with average RGH values of −0.13 and +0.13 cm respectively. A significant difference in grazing efficiency was found among recommended perennial ryegrass varieties that are not being recorded by mechanically harvested simulated grazing protocols. A variety reappraisal that included grazing efficiency could identify varieties capable of improving on‐farm livestock productivity from grass. [ABSTRACT FROM AUTHOR]

Copyright of Julius-Kühn-Archiv is the property of Julius Kuehn Institut and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Experiments were conducted on direct and indirect regeneration from the meristem tip and mature caryopsis explants of Lolium perenne L. 'Numan' and 'Grassland'. De-husked caryopses were cultured both intact and longitudinally sliced on MS media supplemented with 2,4-D alone, and in combinations with BA. The highest percentage of callus induction obtained from intact-sliced caryopses were 71 and 87% for 'Grassland' on MS basal medium supplemented with 6 mg L-1 2,4-D+ 0.02 mg L-1 BA, and 5 mg L-1 2,4-D. While, for 'Numan', the highest callus induction was achieved by the same explants as 55% and 72% with 5 mg L-1 2,4-D + 0.02 mg L-1 BA, and 4 mg L-1 2,4-D + 0.02 mg L-1 BA, respectively. The best regeneration medium for 'Grassland' was MS medium supplemented with 10 g L-1 maltose and 2 mg L-1 ABA. In a separate experiment, meristem tip cultures were incubated on two type combination of plants growth regulators along with control treatment. The best regeneration rate was obtained in both cultivars on MS medium supplemented with 0.1 mg L-1 2,4-D + 0.5 mg L-1 Kin. Plantlets with well-developed roots were transferred to greenhouse condition. Four weeks later, all acclimatized plants were survived. [ABSTRACT FROM AUTHOR]

The objective of this study was to examine the effect of wintering pregnant, nonlactating dairy cows outdoors on either kale or grass, fed in 1 [11 kg of dry matter (DM) of kale or grass + 3 kg of DM of baled barley straw offered in the morning] or 2 allocations (5.5 kg of DM of kale or grass grazed + 1.5 kg of DM barley straw offered morning and afternoon) per day. The body condition score (BCS) gain over the 47-d winter feeding period was higher for grass-fed (0.5 BCS units) than kale-fed cows (0.3 BCS units), but was unaffected by feeding frequency. Forage DM utilization was higher for kale-fed (97%) than grass-fed cows (76%), leading to higher estimated dry matter intake (DMI) in kale-fed (10.7 kg of DM/cow per day) than grass-fed cows (7.7 kg of DM/cow per day). Forage DM utilization and estimated DMI were not affected by feeding frequency. Prehension bite rate was greater for grass-fed (37.3 bites/min) than kale-fed cows (7.6 bites/min), but more mastication bites were required for kale-fed cows. Cumulative DMI after 2, 3, and 6 h was greater in cows allocated forage once than twice a day and for kale than grass after 3 and 6 h. Mean eating time was greater for cows offered forage once (477 min) than twice (414 min) per day. In conclusion, increasing feeding frequency from once to twice per day decreased the intake rate within the first 6 h after allocation, but did not affect total daily DMI, DM utilization or BCS gain. Thus, moving cows more frequently would not have any significant advantage. It may increase labor requirements, thereby creating a more challenging wintering management than feeding once per day. [ABSTRACT FROM AUTHOR]

Aims: During the first days after harvest of Lolium perenne L., N remobilized from roots and stubble forms the main N source for regrowth. Low N uptake from the soil during this period may lead to N loss if N fertilizer is applied too soon. Furthermore, temporary N deprivation has been found to stimulate root growth. We therefore hypothesized that a strategic delay in N application after harvest may improve N-use efficiency of L. perenne grassland by increasing root biomass and reducing N loss. Methods: In a laboratory and field experiment with L. perenne, we delayed N fertilizer application after harvest for 0, 3, 6, 9 and 12 days, repeated this for up to six harvest cycles, and determined effects on herbage yield, herbage N uptake and root biomass. Results: In both experiments, delaying N application for up to 12 days had no significant effect on root biomass or total herbage N uptake, but it significantly reduced total herbage yield in the laboratory experiment. Total yield tended to be highest when N application was delayed for 3 days. Two growth periods in the field experiment showed significantly higher N uptake when N application was delayed, possibly due to rainfall-induced N losses in the treatments with shorter delay. Conclusions: Our results do not provide evidence that delaying N application improves N-use efficiency of L. perenne grassland by increasing root biomass. However, strategic timing of N fertilizer application based on rainfall forecasts could contribute to improve N-use efficiency by reducing N losses from leaching and denitrification. [ABSTRACT FROM AUTHOR]

In central Mexico there animal production systems whose major component using pure and associated grasslands. The objective of this research was to evaluate four associations, two grasses and legume planted in different proportions. Treatments consisted of the following associations: 20-40-40, 00-50-50, 40-20-40, and 50-00-50% of orchard grass (Ov), perennial ryegrass (Ba) and white clover (Tr) respectively. The treatments were randomly distributed in 12 experimental plots of 9 and 8 m, according to a design of a randomized complete block with three replications. Dry matter yield, growth rate, botanical and morphological composition and plant height were evaluated. In the association's annual yield higher performance were presented; 40-20-40 and 20-40-40 with 20.182 and 19.146 kg DM ha-1 respectively and the lowest 00-50-50 association with 15.896 kg DM ha-1. The Association; 40-20-40 is the highest annual growth rate presented with 56 kg DM ha-1 d-1. Regardless of the season, botanical and morphological composition associations; 20-40-40, 40-20-40 and 50-00-50 which was higher clew sheet presented with an average of 50%, the winter season were the highest percentage of ryegrass sheet presented to the association 00-50-50 to 32%. Regardless of the association in the spring season it was where greater height was obtained with an average of 37 cm and the lowest was in winter with an average of 15 cm. In conclusion the association; 40-20-40 was better in annual yield growth rate and lower height and the association was 00-50-50. [ABSTRACT FROM AUTHOR]

The grass plant comprises leaf, pseudostem, true stem (including inflorescence) and dead material. These components differ in digestibility, and variations in their relative proportions can affect sward quality. The objective of this study was to determine the change in the proportion and organic matter digestibility ( OMD) of leaf, pseudostem, true stem and dead components of four perennial ryegrass cultivars (two tetraploids: Astonenergy and Bealey and two diploids: Abermagic and Spelga) throughout a grazing season. The DM proportions and in vitro OMD of leaf, pseudostem, true stem and dead in all cultivars were determined during ten grazing rotations between May 2011 and March 2012. There was an interaction between rotation and cultivar for leaf, pseudostem, true stem and dead proportions. In May and June, Astonenergy had the highest leaf and lowest true stem proportion ( P < 0·05). From July onwards, there was no difference in leaf or true stem proportion between cultivars. Bealey had the highest annual mean OMD (752 g kg−1) and Spelga the lowest (696 g kg−1; P < 0·05). The OMD followed the order leaf > pseudostem > true stem > dead. Bealey had the highest combined leaf and pseudostem proportion 0·92, which explains why it had the highest OMD. In this study, the tetraploid cultivars had the highest leaf and pseudostem proportion and OMD. For accurate descriptions of a sward in grazing studies and to accurately determine sward morphological composition, pseudostem should be separated from true stem, particularly during the reproductive stage when true stem is present. [ABSTRACT FROM AUTHOR]

The results of the research present contents of photosynthetic pigments of five varieties of plant Lolium perenne L. Ukrainian breeding. They include analysis of chlorophyll fluorescence induction of plants L. perenne L. and estimation of the photosynthetic apparatus of plants and the state of the pigment complex of the deciduous apparatus. Recommendations on the installation of lawn with 5 varieties plants of L. perenne L. Ukrainian breeding is given. [ABSTRACT FROM AUTHOR]

Highlights: [•] Application of trinexapac-ethyl plant growth regulator reduced stem length and controlled lodging in perennial ryegrass across nine diverse lodging environments. [•] Trinexapac-ethyl consistently increased seed yield and harvest index in perennial ryegrass. [•] Timing trinexapac-ethyl applications between BBCH stages 32 and 51 produced the best seed yield results. [•] Seed yield increases resulting from trinexapac-ethyl application were attributable to a greater number of seeds spikelet−1 and improvements in seed set. [Copyright &y& Elsevier]

Abstract: Sucrose transport between source and sink tissues is supposed to be a key-step for an efficient regrowth of perennial rye-grass after defoliation and might be altered by light conditions. We assessed the effect of different light regimes (high vs low light applied before or after defoliation) on growth, fructans and sucrose mobilization, as well as on sucrose transporter expression during 14 days of regrowth. Our results reported that defoliation led to a mobilization of C reserves (first sucrose and then fructans), which was parallel to an induction of LpSUT1 sucrose transporter expression in source and sink tissues (i.e. leaf sheaths and elongating leaf bases, respectively) irrespective to light conditions. Light regime (high or low light) had little effects on regrowth and on C reserves mobilization during the first 48 h of regrowth after defoliation. Thereafter, low light conditions, delaying the recovery of photosynthetic capacities, had a negative effect on C reserves re-accumulation (especially sucrose). Surprisingly, high light did not enhance sucrose transporter expression. Indeed, while light conditions had no effect on LpSUT1 expression, LpSUT2 transcripts levels were enhanced for low light grown plants. These results indicate that two sucrose transporter currently identified in Lolium perenne L. are differentially regulated by light and sucrose. [Copyright &y& Elsevier]

Abstract: The increasing atmospheric CO2 and heavy metal contamination in soil are two of the major environmental problems. Knowledge of the Cd stress coping mechanisms is needed to understand the regulation of the plants’ metabolism under the increasing atmospheric CO2 levels. Lolium perenne L. was grown hydroponically under two concentrations of atmospheric CO2 (360 and 1000μLL−1) and six concentrations of cadmium (0–160μmolL−1) to investigate Cd uptake, Cd transportation, and variations in phytochelatin (PC) concentration. Cd concentrations in roots and shoots were decreased, but transport index (Ti) was increased under elevated CO2 compared to ambient CO2. Regardless of CO2 concentrations, Cd and PC concentrations, especially the concentrations of high molecular weight PCs (PC4, PC5, PC6) were higher with increasing Cd concentration in growth media and longer Cd exposure time. Under the elevated CO2, more high molecular weight PCs (PC4, PC5, PC6) in shoots and roots were synthesized compared to ambient CO2, with higher SH:Cd ratio in roots as well. These results indicate that under elevated CO2, L. perenne may be better protected against Cd stress with higher biomass, lower Cd concentration and better detoxification by phytochelatins. [Copyright &y& Elsevier]

The aim of the present study was to investigate the relationship between Lolium perenne L. uptake of Cd, Cu, Pb, and Zn in sludge amended soils and soil availability of these elements assessed by soil sequential extraction. A greenhouse experiment was set with three representative soils of the Pampas Region, Argentina, amended with sewage sludge and sewage sludge enriched with its own incinerated ash. After the stabilization period of 60 days, half of the pots were sampled for soil analysis; the rest of the pots were sown with L. perenne and harvested 8, 12, 16 and 20 weeks after sowing, by cutting just above the soil surface. Cadmium and Pb concentrations in aerial tissues of L. perenne were below detection limits, in good agreement with the soil fractionation study. Copper and Zn concentration in the first harvest were significantly higher in the coarse textured soil compared to the fine textured soil, in contrast with soil chemical speciation. In the third harvest, there was a positive correlation between Cu and Zn concentration in aerial biomass and soil fractions usually considered of low availability. We conclude that the most available fractions obtained by soil sequential extraction did not provide the best indicator of Cu and Zn availability to L. perenne. [Copyright &y& Elsevier]

Abstract: Forage grass seed yields are often low and variable with only 10–20% of the above ground matter harvested as seed. Seed yield is affected by the amount of carbohydrate transported to the seed. However, information regarding the storage and mobilisation of carbohydrates during reproductive development in forage grasses is limited and the contribution of stored and current assimilate to seed yield from vegetative tissues is equivocal. To identify whether the total amount of carbohydrate in the plant might be limiting seed yield, and the contribution of vegetative and reproductive tissues to seed yield, the pattern of accumulation of water-soluble carbohydrates (WSC) and their remobilisation was investigated in field-grown perennial ryegrass (Lolium perenne L.) plants. Tillers were sampled from early head emergence through to harvest. Amounts of WSC in leaf blades, leaf sheaths, internodes and reproductive heads of the tillers were measured in two ways. Firstly, WSC were estimated indirectly by changes in tissue dry weight. These changes were then used to determine any apparent translocation of WSC from vegetative tissues to the developing seed. Secondly, WSC concentration was measured directly. Low molecular weight (LMW) and high molecular-weight (HMW) WSC were extracted from vegetative and reproductive tissues and the concentrations quantified using a colorimetric anthrone assay. The seed yield of the crop was high (2950kgh−1) and the dry weights and the amount of LMW and HMW WSC in vegetative and reproductive tissues changed significantly during reproductive development. High concentrations of HMW WSC were found in the internodes post head emergence and these concentrations continued to increase during seed fill through to harvest. Total dry weight of the internodes also increased over the same period. In contrast, in the leaf blades and leaf sheaths, total dry weight decreased only slightly while the initial low concentrations of WSC steadily declined. In the heads, WSC increased significantly during seed fill and subsequently declined while the dry weight continued to increase through to harvest. The ratio of LMW and HMW WSC also changed during development depending on the tissue type and growth stage. The present study indicates that the seed head itself maybe an important factor driving seed fill. Knowledge of the mechanisms that underlie carbohydrate partitioning to the seed could in future result in significantly higher yields. [Copyright &y& Elsevier]

Abstract: Plant lipids are complex, polar and highly unsaturated constituents of membranes. During collection and/or handling of a plant sample, the membrane integrity gets lost due to plant injury and losses of fatty acids (FA) can occur as a result of oxidative or enzymatic processes. Quantitative and qualitative effects of various post-harvest treatments on the concentrations and proportions of FA in herbage are not well known. In this study, effects of various post-harvest treatments regarding conditions following sample collection of perennial ryegrass were examined. The handling of the samples, before applying all pre-treatments, was uniform, i.e., all samples were put in a cooling box at 4°C and transported to the lab for approximately 30min. The moment when the samples arrived to the lab was considered “time zero”, and the applications of treatments started. We studied effects of two ways of sample handling (dry ice vs. no dry ice), two frozen storage temperatures (−80°C vs. −18°C) and two durations of frozen storage (1 day vs. 2 weeks) on concentrations and proportions of FA in cut herbage. The effects of the treatments appeared to be small and inconsistent, with exception of prolonged storage, which decreased FA concentrations, and increased the proportion of α-linolenic acid (C18:3). Contrary to expectation, using dry ice (rapid freezing) did not differ from slow freezing (without dry ice). Also, there were no effects of storage temperature (−80 or −18°C). Future research questions are discussed. [Copyright &y& Elsevier]

Biosolids (B) may contain various types of environmental pollutants, which can exert phytotoxic effects in plants. The effect of aqueous extracts on seed germination and the primary root growth of discaria (Discaria americana) obtained from different soil application rates of B and a mixture of B and incinerated B were investigated. The objective was to evaluate the potential use of discaria for the stabilization of B-amended soils. Ryegrass (Lolium perenne L.) was used for comparison. Compared to ryegrass, relative seed germination (RSG) was significantly lower for discaria. RSG of discaria and rye grass was inversely correlated to the electrical conductivity of extracts, although a significant adverse effect was only observed for ryegrass with the highest dose of the mixture of B and incinerated B. This dose also produced a reduction in the germination index of discaria, which could not be correlated with the parameters studied. The B extracts did not exert any significant adverse effect on the relative root growth of both species. An increase in relative root growth and germination index was observed for discaria with a field application rate equivalent of 156 t DW ha-1 of B, suggesting a stimulating effect of the amendment. The results obtained in this study suggest that germinated seedlings of discaria might be used for the stabilization of B-amended soils. However, further greenhouse and field experiments should be performed to confirm these findings. [ABSTRACT FROM AUTHOR]

A field experiment with nine different turfgrass mixtures comprising 2,135; 4,270; 8,540 viable seeds per m² of Lolium perenne L. in combination with 8,430; 16,860; 33, 720 viable seeds per m² of Poa pratensis L. was established in Vìtrov (620 m a.s.l) in Czech republic in 2004 to evaluate their shoot density during two vegetation years. The number of L. perenne tillers increased with a higher total seeding rate and a higher proportion in the seed mixture. The shoot density of P. pratensis was in negative correlation with the number of L. perenne tillers, especially with higher total seeding rates of the mixture. [ABSTRACT FROM AUTHOR]

Copyright of Ekologija is the property of Lithuanian Academy of Sciences Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Winter hardiness is a quantitative trait and the lack of it limits geographic distribution of ryegrass. Improving winter hardiness is an important breeding goal in ryegrass breeding programs. An understanding of the genetic basis for the component traits of winter hardiness would allow more efficient selection. A three-generation interspecific population of an annual × perennial ryegrass consisting of 152 progenies was used to map quantitative trait loci (QTL) that control winter hardiness-related traits including fall growth (FG), freezing tolerance (FT), and winter survival (WS) over 2 years. A total of 39 QTL were identified for the three traits from both the female parental (MFA) and the male parental (MFB) maps, of which 13 were for FG, 6 for FT, and 20 for WS. The proportion of phenotypic variation explained by individual QTL ranged from 10.4 to 22.1%. Both FG and FT were positively correlated with WS. Common QTL were detected between FG, FT, and WS. The QTL associated with WS on linkage groups (LGs) 4 and 5, and the QTL for FT on LG 5 were consistently identified over years and maps. These consistent QTL might serve as potential tools for marker-assisted selection to improve ryegrass winter hardiness. [ABSTRACT FROM AUTHOR]

Annual ( Lolium multiflorum Lam.) and perennial ( Lolium perenne L.) ryegrasses are two important forage and turfgrass species. Improving the digestibility of forage by decreasing fiber content is a major goal in forage crop breeding programs. An annual × perennial ryegrass interspecific hybrid population was used to map quantitative trait loci (QTLs) for fiber components, neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL), and crude protein (CP). Samples were harvested three times in August and September 2003 and August 2004, respectively. Simple interval mapping was used to detect QTLs from both the male and female parental maps previously developed for the population. Fiber components were all correlated positively with each other and were negatively correlated with CP. The largest correlations were between NDF and ADF with r = 0.86, 0.72, and 0.82 for each of the three harvests. All four traits showed intermediate broad-sense heritability values ranging from 0.35 to 0.72. A total of 63 QTLs were detected for the four traits measured over the three harvests from both the female and male maps. Coincident QTLs were detected on linkage groups (LGs) 2, 6, and 7 for NDF, LGs 1, 2, and 7 for ADF, LGs 6 and 7 for ADL, and LG 2 for CP, respectively. Coincident QTLs were also detected on LGs 2, 6, and 7 for NDF and ADF, providing evidence of the genetic basis of the observed high level of phenotypic correlation. The QTLs on LGs 2, 6, and possibly 7 for fiber components were co-located on the same LG as several lignin biosynthetic genes from perennial ryegrass. [ABSTRACT FROM AUTHOR]

Determining haplotype‐specific DNA sequence information is very important in a wide range of research fields. However, no simple and robust approaches are currently available for determining haplotype‐specific sequence information. We have addressed this problem by developing a very simple and robust haplotype‐specific sequencing approach. We utilise the fact that DNA sequencing polymerases are sensitive to 3′end mismatches in the sequencing primer. By using two sequencing primers with 3′end corresponding to the two alleles in a given SNP locus, we are able to obtain allele‐specific DNA sequences from both alleles. We evaluated this direct haplotype‐specific approach by determining haplotypes within the intron 2 sequence of the fructan‐6‐fructosyltransferase ( 6 ‐ ft ) gene in Lolium perenne L . We obtained reliable haplotype‐specific sequences for all primers and genotypes evaluated. We conclude that the haplotype‐specific sequencing is robust, and that the approach has a potentially very wide application range for any diploid organism. [ABSTRACT FROM AUTHOR]

Three sludge types from the same treatment stream (undigested liquid, anaerobically digested liquid and dewatered, anaerobically digested cake) were used in a field based tub study. Amendments (4, 8, and 16 Mg dry solid (ds) ha−1) were incorporated into the upper 15 cm of a sandy loam soil prior to sowing with rye-grass (Lolium perenne L.). Nitrogen transformations in the soil were determined for the 80 d period following incorporation. Nitrogen uptake and crop yield were measured in the cut sward 35 and 70 d after sowing. The study showed that application of sewage sludge at rates as low as 4 Mg ha−1 can have a nutritional benefit to rye-grass over the two harvests. Differences in N transformation, and hence crop nutritional benefit, between sludge types were evident throughout the experiment. In particular, the dewatering process changed the mineral N characteristics of the anaerobically digested sludge, which, when not dewatered, outperformed the other sludges in terms of yield and mineralisation rate at both harvests. The dewatered sludge produced the lowest yield of rye-grass. The undigested liquid sludge had the lowest foliar N and soil NO3–N concentrations, possibly immobilised as the large oxidisable C component of this sludge was metabolised by the microbial biomass. Correlation data support the concept of preferential uptake of NH4–N over NO3–N in Lolium perenne. Results are discussed in the context of managing sludge type and application for a plant nutrient source and NO3–N release. [Copyright &y& Elsevier]

A 13C/12C mass spectrometer was interfaced with a open gas exchange system including four growth chambers to investigate CO2 exchange components of perennial ryegrass ( Lolium perenne L.) stands. Chambers were fed with air containing CO2 with known δ13C ( δCΟ2−2.6 or −46.8‰). The system did not fractionate C isotopes and no extraneous CO2 leaked into chambers. The on-line 13C discrimination (Δ) of ryegrass stands in light was independent of δCΟ2 when δCΟ2 was constant. The δ of CO2 exchanged by the stands in light ( δNd) and darkness ( δRn) differed by 0.7‰, suggesting some Δ in dark respiration at the stand-level. However, Δ decreased by ∼ 10‰ when δCΟ2 was switched from −46.8 to −2.5‰, and increased by ∼ 10‰ following a shift from −2.6 to −46.7‰ due to isotopic disequilibria between photosynthetic and respiratory fluxes. Isotopic imbalances were used to assess (non-photorespiratory) respiration in light and the replacement of the respiratory substrate pool(s) by new photosynthate. Respiration was partially inhibited by light, but increased during the light period and decreased in darkness, in association with temperature changes. The labelling kinetics of respiratory CO2 indicated the existence of two major respiratory substrate pools: a fast pool which was exchanged within hours, and a slow pool accounting for ∼ 60% of total respiration and having a mean residence time of 3.6 d. [ABSTRACT FROM AUTHOR]

The stay‐green mutation of the nuclear gene sid results in inhibition of chlorophyll degradation during leaf senescence in grasses, reducing N remobilization from senescing leaves. Effects on growth of Lolium perenne L. were investigated during N starvation (over 18 d) and after severe defoliation, when leaf growth depends on the remobilization of internal N. Rates of dry matter production, partitioning between shoots and roots, and re‐partitioning of N from shoots to roots were very similar in stay‐green and normal plants under N starvation. Km and Vmax for net uptake of NH4+ were also similar for both genotypes, and Vmax increased with the duration of N deprivation. The mutation had little effect on recovery of leaf growth following severe defoliation, but stay‐green plants recommenced NO3– and K+ uptake 1 d later than normal plants. Import of remobilized N into new leaves was generally similar in both lines. However, stay‐green plants remobilized less N from stubble compared with normal plants. It was concluded that the sid locus stay‐green mutation has no significant adverse effect on the growth of L. perenne during N starvation, or recovery from severe defoliation when plants are grown under an optimal regime of NO3– supply both before and after defoliation. The absence of any effect on leaf dry matter production implies that the difference in foliar N availability attributable to this mutation has little bearing on productivity, at least in the short to medium term. [ABSTRACT FROM PUBLISHER]

(1) Background: The use of natural products based on essential oils (EO) is nowadays arousing great interest as an alternative method to control plant pathogens and weeds. However, EO possess low bioavailability and are highly volatile, and their encapsulation in hydroxypropyl-ß-cyclodextrin (HP-β-CD) could be a means to enhance their stability and maintain their bioactivity. Thus, the current study aims at investigating, in the presence and the absence of HP-β-CD, the antifungal and phytotoxic activities of nine EO, distilled from plant species belonging to Alliaceae, Apiaceae, and Cupressaceae families, with considerations for their chemical composition. (2) Methods: EO antifungal activity was assessed by direct contact and volatility assays against Fusarium culmorum, a major phytopathogenic fungi, while phytotoxic effects were evaluated against lettuce (Lactuca sativa L.) and rye-grass (Lolium perenne L.), by seedling's emergence and growth assays. (3) Results: These EO inhibit fungal growth in both direct contact and volatility assays, with half-maximal inhibitory concentrations (IC50) ranging from 0.01 to 4.2 g L−1, and from 0.08 up to 25.6 g L−1, respectively. Concerning phytotoxicity, these EO have shown great potential in inhibiting lettuce (IC50 ranging from 0.0008 up to 0.3 g L−1) and rye-grass (IC50 ranging from 0.01 to 0.8 g L−1) seedlings' emergence and growth. However, the EO encapsulation in HP-β-CD has not shown a significant improvement in EO biological properties in our experimental conditions. (4) Conclusion: All tested EO present antifungal and phytotoxic activities, with diverse efficacy regarding their chemical composition, whilst no increase of their biological effects was observed with HP-β-CD. [ABSTRACT FROM AUTHOR]

The rapid identification and quantitation of alkaloids produced by Epichloë endophyte-infected pasture grass is important for the agricultural industry. Beneficial alkaloids, such as peramine, provide the grass with enhanced insect protection. Conversely, ergovaline and lolitrem B can negatively impact livestock. Currently, a single validated method to measure these combined alkaloids in planta does not exist. Here, a simple two-step extraction method was developed for Epichloë-infected perennial ryegrass (Lolium perenne L.). Peramine, ergovaline and lolitrem B were quantified using liquid chromatography–mass spectrometry (LC–MS). Alkaloid linearity, limit of detection (LOD), limit of quantitation (LOQ), accuracy, precision, selectivity, recovery, matrix effect and robustness were all established. The validated method was applied to eight different ryegrass-endophyte symbiota. Robustness was established by comparing quantitation results across two additional instruments; a triple quadruple mass spectrometer (QQQ MS) and by fluorescence detection (FLD). Quantitation results were similar across all three instruments, indicating good reproducibility. LOQ values ranged from 0.8 ng/mL to 6 ng/mL, approximately one hundred times lower than those established by previous work using FLD (for ergovaline and lolitrem B), and LC–MS (for peramine). This work provides the first highly sensitive quantitative LC–MS method for the accurate and reproducible quantitation of important endophyte-derived alkaloids. [ABSTRACT FROM AUTHOR]