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Bagasse remaining after extracting the juice from crop biomass for ethanol production could be preserved as silage and used in animal feedstock, but the nutritive and conservation attributes of bagasse silage from sweet sorghum ( Sorghum bicolor (L.) Moench) and sweet pearl millet ( Pennisetum glaucum (L.) R.Br) are not well known. We evaluated the nutritive and conservation attributes of silages made with the bagasse of two species (sweet pearl millet and sweet sorghum) harvested on two dates (August and September) at two sites in Québec (Canada) and ensiled after four delays between biomass chopping and pressing (0.5, 2, 4, and 6 h). Bagasse silages made in laboratory silos were considered well preserved (pH ≤ 4.0, NH-N < 100 g kg total N, lactate > 30 g kg DM, no propionic and butyric acids) regardless of species, harvest date, or delay between biomass chopping and pressing. Sweet pearl millet and sweet sorghum bagasse silages had similar total N concentration, in vitro true digestibility of dry matter (IVTD), and in vitro neutral detergent fiber digestibility (NDFD). Bagasse silage made from biomass harvested in August rather than in September had a 4 % greater concentration of total N, a 4 % greater IVTD, and a 8 % greater NDFD. The delay between biomass chopping and pressing did not affect the nutritive and conservation attributes of silages. Juice extraction from the biomass of sweet pearl millet and sweet sorghum did not impair attributes of good silage fermentation but it reduced its nutritive value. [ABSTRACT FROM AUTHOR]

For more than fifty years, the public service has been a nexus of media organization, development, and regulation in Canada and several countries in the world. Is public service media still relevant in the age of the internet and digital networks? Before directly addressing this question, this article broadly examines the path that has been hewn by public service media, from its origins-when it played a guiding and influential role in the media landscape-through to today-when its dominance is in question. It links together a set of factors that have triggered a process of redefining public service media, one that may allow it to play the new social and cultural role that is expected of it in contemporary societies. [ABSTRACT FROM AUTHOR]

Sweet pearl millet [ Pennisetum glaucum (L.) R.Br] and sweet sorghum [ Sorghum bicolor (L.) Moench] have been identified as possible ethanol feedstocks because of their high biomass yield and concentration of readily fermentable sugars, but the effects of harvest dates and delays between biomass harvest and pressing on sugar yield and concentration are poorly known. The objective of this study was to determine the effects of two species, two harvest dates (August and September), and four delays between chopping and pressing (0.5, 2, 4, and 6 h) on yields and concentrations of nonstructural carbohydrates [NSC = water-soluble carbohydrates (WSC) + starch] of the biomass, bagasse, and extracted juice. An experiment was conducted at two contrasted sites in Québec, Canada [Saint-Augustin-de-Desmaures, 2,300-2,500 corn heat units (CHU); and Sainte-Anne-de-Bellevue, 2,900-3,100 CHU], in 2010. Sweet sorghum had lower biomass yield (15.8 vs. 20.4 Mg dry matter (DM) ha), but greater biomass NSC concentration (242 vs. 128 g kg DM), extracted juice NSC concentration (61 vs. 42 g L) and yield (2.8 vs. 2.2 Mg ha) than sweet pearl millet. Delaying harvest increased biomass yield (+7 Mg DM ha), NSC concentrations of biomass (+97 g kg DM), bagasse (+70 g kg DM), and extracted juice (+38 g L), and NSC yield from the extracted juice (+1.6 Mg ha). The maximum extracted juice NSC yield (3.9 Mg ha) was obtained with sweet sorghum harvested in September. Delaying pressing the biomass up to 6 h after chopping did not affect NSC concentration and yield of the extracted juice. [ABSTRACT FROM AUTHOR]

The article discusses challenges faced by the Québec press in the digital age. Topics discussed include threatened existence of newspapers and newspaper press due to the advancement in technology posing a competition with internet in digital age, development of shorter and faster ways of communication by various mass public transportation sites and internet advancement providing latest news on several website, smartphone and laptops avoiding from the wait for the morning paper.

Abstract: The energy to protein ratio of forages affects ruminant N use efficiency but little is known on its variation among legume–grass complex mixtures. Our objective was to determine the variation in the ratio of forage readily-available energy to proteins along with the associated variation in yield and digestibility by mixing three or four grass species in combination with one of two legume species. Four grass mixes [#1 – timothy (Phleum pratense L.), meadow fescue (Festuca elatior L.), and Kentucky bluegrass (Poa pratensis L.); #2 – timothy, meadow fescue, reed canarygrass (Phalaris arundinacea L.), and Kentucky bluegrass; #3 – tall fescue [Schedonorus phoenix (Scop.) Holub], meadow bromegrass (Bromus biebersteinii Roemer & J.A. Schultes), orchardgrass (Dactylis glomerata L.), and Kentucky bluegrass; #4 – tall fescue, meadow bromegrass, reed canarygrass, and Kentucky bluegrass] were grown with either alfalfa (Medicago sativa L.) or birdsfoot trefoil (Lotus corniculatus L.) at two sites with measurements taken on two simulated grazing events of the first post-establishment year. The water soluble carbohydrate (WSC) to crude protein (CP) ratio among the eight legume–grass mixtures ranged from 0.64 to 1.04, while the ratio of readily fermentable carbohydrate fractions A and B1 to readily soluble protein fractions A and B1 [(CA+CB1)/(PA+PB1)], estimated using the Cornell net carbohydrate and protein system, ranged from 4.33 to 5.64. This significant variation in the two ratios used to characterize the energy to protein balance was due to both legume species and grass mixes. Alfalfa-based complex mixtures had greater WSC/CP and (CA+CB1)/(PA+PB1) than birdsfoot trefoil-based mixtures (0.94 vs. 0.69; 5.42 vs. 4.47) but a lower in vitro true digestibility (IVTD; 902 vs. 913g/kg dry matter, DM). The grass species mix #2 (timothy, meadow fescue, reed canarygrass, and Kentucky bluegrass) provided the best combination of high readily-available energy to protein ratio (WSC/CP=0.87; (CA+CB1)/(PA+PB1)=5.08), high DM yield, and average IVTD. The complex mixtures including alfalfa and meadow fescue had the best readily-available energy to protein ratio and DM yield. Our results confirm the possibility of improving the balance between readily-available energy and proteins through the choice of species in complex mixtures made of one legume and three or four grass species. [Copyright &y& Elsevier]

The author offers here a personal account of the development of communication research in Quebec, remembering the most significant steps of his career as a researcher. He recalls his training years in social sciences, his beginnings at UQAM, his involvement in starting up graduate studies and founding the GRIGS research group, publishing the journal TIS, team researching and international cooperation. A contribution to the historiography of information communication sciences in Canada. [ABSTRACT FROM AUTHOR]

Nonstructural carbohydrate (NSC) concentration in alfalfa (Medicago sativa L.) increases by cutting in the afternoon (PM) and wilting in wide swaths but the impact of this greater concentration during silage fermentation is not well known. We determined if increased NSC concentration associated with PM-cutting and wide swathing is maintained during fermentation and whether it affects conservation attributes of wilted alfalfa silages. The cutting time effect was measured in spring growth and summer regrowth of 2007 and 2008 (Experiment 1) while the combined effect of cutting time and swathing type was measured in spring growth and summer regrowth of 2008 (Experiment 2). Alfalfa was field wilted [≈390 g dry matter (DM) kg-1 fresh matter] and ensiled in mini-silos. Differences in alfalfa NSC concentration at ensiling (10 to 36 g kg-1 DM) due to PMcutting combined or not with wide swaths were reduced during silage fermentation to between 0 and 15 g kg-1 DM mostly through a reduction in soluble carbohydrate concentration. When NSC concentration differences at ensiling were > 10 g kg-1 DM, silage conservation attributes were improved with lower pH (-0.2 to -0.4), greater concentrations of lactate (+8 to +20 g kg-1 DM), and lower concentrations of volatile fatty acids (-8 to -11 g kg-1 DM) and NH3-N (-6 to -11 g kg-1 total N). Improved silage conservation attributes along with a greater residual starch concentration from NSC-enriched alfalfa has the potential to improve milk production. [ABSTRACT FROM AUTHOR]

The author presents a personal reading of the pioneering contribution to communication studies made by two Canadian thinkers: Marshall McLuhan and Harold A. Innis. Running counter to the general trend stressing their similarities, he highlights their differences. Rejecting their technological-determinist standpoint, the author proposes a comprehensive and critical summary of their analytical frameworks and methodologies, seeking to assess the influence they have had on his own perspective, tracing the contributions they have made to the evolution of communication research. The author's viewpoint is condensed in the title: we should go back from McLuhan to Innis, from a framework inspired by the global-village metaphor to one based on the expansion of empire. [ABSTRACT FROM AUTHOR]

Near-infrared reflectance spectroscopy (NIRS) is a rapid, inexpensive, and accurate analysis technique for a wide variety of materials, and it is increasingly used in soil science. The objectives of our study were to examine the potential of NIRS to predict (i) soil P extracted by two methods [Mehlich 3 (M3P) and water (Cp)], soil total P (TP), annual crop P-uptake, and annual P-budget, and (ii) other soil chemical properties [total C (TC), total N (TN), pH, and K, Al, Fe, Ca, Mg, Mn, Cu, and Zn extracted by Mehlich 3]. Soil samples (n = 448) were taken over a 7-yr period from an experimenral site in Lévis (Québec, Canada) where timothy (Phleum pratense L.) was grown under four combinations of P and N fertilizer. The NIRS equations were developed using 80% of the samples for calibration and 20% for validation. The predictive ability of NIRS was evaluated using the coefficient of determination of validation (Rv²) and the ratio of standard error of prediction to standard deviation (RPD). Results show that M3P, Cp, crop annual P-uptake, and annual P-budget were not accurately predicted by NIRS (R2 < 0.70 and RPD < 1.75). Similar results were found for K and Cu. However, NIRS predictions were moderately useful for TP, TN, Fe, and Zn (0.70 ≤ Rv² < 0.80 and 1.75 ≤ RPD < 2.25), moderately successful for TC and Al (0.80 ≤ R² < 0.90 and 2.25 ≤ RPD < 3.00), successful for pH and Mg (0.90 ≤ R² ≤ 0.95 and 3.00 ≤ RPD ≤ 4.00), and excellent for Ca and Mn (Rv² > 0.95 and RPD > 4.00). The NIRS predictive ability of several soil properties appears to be related to their relationship with soil organic C. Although NIRS can predict several soil properties, prediction of total P was the only soil P-related property, correlated to soil C, that was moderately useful. [ABSTRACT FROM AUTHOR]

This article presents a commentary on the pursuit of creative economies in Great Britain. It relates the trend to the motion of creative industries popularized by the Labour Party. It also explores the relationship between creative economies and information economy or knowledge economy. In addition, the article warns about the difficulty in applying the model of the creative economy developed by Great Britain to other countries.

This article aims to analyze authors' contributions published in Distances et Savoirs (D & S) on the topic of distance education in the context of globalization. It offers an inventory of questions, problems, and issues the authors have selected; a description of the way they have studied them; and a synthesis of conclusions they have reached. It also pinpoints what they have ignored, silenced, or left in the shadows. The corpus includes twenty-four papers. After a short reflection on the background set up by the globalization process, the outcomes presentation is structured by distributing the different objects into three categories: the international regulation of distance education, the e-learning experiments, and information and communication technologies (ICT) for development. A few comments highlight valuable contributions, as well as a few omissions, in the researchers' works published in D & S. [ABSTRACT FROM AUTHOR]

Abstract: Forage non-structural carbohydrates (NSC) are an important source of energy readily available to rumen microbes. Sampling procedures that quickly reduce plant metabolic activity after cutting and preserve macromolecular structures are required for accurate estimation of forage NSC concentration and other nutritive value attributes. Although several drying procedures exist, their efficiency to reflect composition of fresh samples is unclear. We compared five drying procedures on fresh samples of timothy (Phleum pratense L.) and alfalfa (Medicago sativa L.): (1) oven-drying at 55°C for 48h; (2) high-temperature pretreatment at 100°C for 1h followed by oven-drying at 55°C for 48h; (3) freezing pretreatment at −20°C for 1mo followed by oven-drying at 55°C for 48h; (4) microwave pretreatment for 1min followed by oven-drying at 55°C for 48h; and (5) freezing at −20°C for 1mo followed by freeze-drying. Starch, sucrose, glucose, fructose, fructans (timothy) or pinitol (alfalfa), N, neutral detergent fibre assayed with a heat-stable amylase (aNDF), acid detergent fibre (ADF), neutral detergent insoluble N (NDIN), and acid detergent insoluble N (ADIN) concentrations, and in vitro true digestibility of DM (IVTD) and digestibility of neutral detergent fibre (dNDF) were determined in the spring growth and summer regrowth of two production years. Soluble carbohydrate (SC) concentration was estimated using the sum of sucrose, glucose, fructose, and fructans or pinitol. The NSC concentration was obtained by adding SC and starch. Averaged across forage species and growth periods, NSC concentrations were similar and generally highest (P<0.001) in freeze-dried samples (89.8mg/g DM), the reference procedure, and the microwave-pretreated samples (86.7mg/g DM); oven-drying at 55°C resulted in the lowest NSC concentration (57.6mg/g DM). Values of other nutritive value attributes with the microwave pretreatment were comparable to those of the other drying procedures, except that it tended to increase forage NDIN. The NDIN concentration was lowest (P<0.001) in freeze-dried samples (2.1mg/g DM) and generally highest in microwave-pretreated samples (7.5mg/g DM). The effect of drying procedure on aNDF, ADF, IVTD, dNDF, and ADIN concentrations varied slightly with forage species and growth period. Principal component analysis (PCA) highlighted the closeness between freeze-drying and microwave pretreatment for the global assessment of the nutritive value of forages, including NSC concentration. Microwave pretreatment should be given greater consideration as an effective and easy-to-use sample preparation procedure for the characterization of the nutritive value of fresh forages. [Copyright &y& Elsevier]

Sweet sorghum and sweet pearl millet are considered promising alternative feedstocks for bioethanol production. Water soluble carbohydrate (WSC) extraction from the stems for first generation ethanol production is practically well mastered. However, structural carbohydrate (SC) release from the bagasse for cellulosic ethanol production still needs to be more understood and improved, especially for sweet pearl millet. In this study, the effects of two bagasse particle sizes (4.5–9 mm and 1 mm) and two pretreatment solutions (NaOH and H2SO4) at two concentrations (1% and 3%) on the release of SC from sweet sorghum and sweet pearl millet bagasse were investigated. After the extraction of juice, the bagasse pretreatment was carried out at 121 °C for 60 min followed by an enzymatic saccharification. Results indicated that hemicellulose and lignin were better solubilized when the bagasse from both crops was pretreated with NaOH than with H2SO4. The highest glucose concentration (320 and 249 g/kg DM of bagasse for sweet sorghum and sweet pearl millet, respectively) was reached after enzymatic saccharification of the bagasse chopped to 4.5–9 mm particle size and pretreated with 3% NaOH. Under these conditions, cellulose saccharification efficiency reached 88% and 73% for sweet sorghum and sweet pearl millet, respectively, while that of hemicellulose saccharification approached 100% for sweet sorghum and reached 90% for sweet pearl millet. Potential first generation ethanol of 80.3 and 60.7 L/kg DM of biomass and cellulosic ethanol of 138.8 and 115 L/kg DM of biomass were estimated for sweet sorghum and sweet pearl millet, respectively. [ABSTRACT FROM AUTHOR]

Climate change is expected to affect the growth and metabolism of both aboveground and belowground parts of most crop species including timothy (Phleum pratense L.), a major forage grass species in northern regions. Our objective was to assess the effects of predicted increases in CO2 concentration and temperature on root chemical composition and degradability of timothy grown under contrasted N fertilization. Timothy was grown in growth chambers under either 400 or 600 μmol mol-1 of CO2 at day and night temperatures of either 22 and 10°C or 25 and 15°C and was fertilized with 0, 60, or 120 kg N ha-1. Root degradability was characterized using two in vitro enzymatic methods: in vitro true digestibility (IVTD) and enzyme-released glucose from cell walls (CW), while root composition was determined for N and C concentrations and enzyme-released hemicellulose and pectin concentrations. Increasing temperature and atmospheric CO2 concentration generally decreased N concentration and increased the C/N ratio and decreased root degradability assessed by the two enzymatic methods under all three N rates. When both factors were considered together, root N concentration was 13% lower and the C/N ratio was 19% greater under predicted future conditions than under current conditions at first harvest. Both enzymatic approaches showed that root degradability was lower under elevated CO2 and temperature compared with current conditions with an estimated average reduction of 6.3% with the IVTD method and 15.5% with the enzyme-released glucose method. Predicted future conditions of elevated CO2 and temperature decreased timothy root degradability across a wide range of N fertilization compared with current conditions and this could increase its potential for soil C sequestration. [ABSTRACT FROM AUTHOR]

Highlights: [•] First calibration of STICS model for timothy. [•] Equations used in CATIMO model for calculating nutritive value indices successfully used and calibrated in STICS. [•] Good overall model performance (LAI, biomass and nutritive value) for various sites and climatic years. [•] Better model performance for simulating the primary growth than the regrowth. [ABSTRACT FROM AUTHOR]

Most methods for soil analysis are based on wet chemistry. Near infrared reflectance spectroscopy (NIRS) is a cost-effective and environmentally sound alternative technique. This study evaluated the effect of sample fineness (0.2, 0.5, 1, and 2mm) and sample cups (transport versus spinning) on the accuracy of NIRS predictions of soil texture, cation-exchange capacity, pH, total C and N, organic C, and potentially mineralizable N (Nmin) using 150 air-dried samples collected from a 15-ha site dominated by Humaquept, Endoaquept, and Dystrochrept soils. The best spectral pretreatment was determined for each property. Principal component analysis (PCA) was used to select samples in calibration and validation sets. Calibration equations were developed using the modified partial least square regression. The accuracy of NIRS prediction was evaluated using three statistics for the prediction set: coefficient of determination (R2), ratio of performance deviation (RPD), and ratio error range (RER). Across the factorial designed treatments, successful calibrations were observed for clay, sand, and Nmin (R2 ≧ 0.90, RPD ≧ 3, RER≧15). Prediction accuracy ofpH was poor (0.51 ⩽R2 ⩽ 0.74, 1.39 ⩽ RPD ⩽ 1.92,6.13 ⩽ RER ⩽8.33), while it was intermediate for remaining properties. Sample fineness of 2 mm appeared to be sufficient since finenesses of 0.2, 0.5, or 1.0 mm did not improve calibration accuracy. These findings at small scale should not be extrapolated and further investigations are required to validate them at a larger scale. [ABSTRACT FROM AUTHOR]

High concentration of nonstructural carbohydrates (NSC) in forages improves ruminant N utilization and performance. The present study evaluated the direct and indirect effects of one cycle of divergent phenotypic selection for NSC in alfalfa along with the diurnal and seasonal stability of the trait. For this purpose, divergent NSC populations were developed (NSC+ and NSC−) and two field trials were established in Quebec, Canada. Forage samples were collected twice a day (morning and afternoon) and three times a year (spring, summer and autumn) and analysed for NSC, crude protein (CP), fibre concentration, digestibility and yield. The NSC+ population maintained greater NSC concentrations than the NSC− population over 2 establishment years (+18%, 129 vs. 109 g/kg) and three production years (+8%, 126 vs. 116 g/kg). Time of cutting and period of harvest had significant effects on alfalfa NSC concentration and other nutritive attributes, but they did not affect the response to selection for NSC concentration. Phenotypic selection for NSC concentration can therefore be used in a recurrent phenotypic selection approach to improve alfalfa nutritive value. [ABSTRACT FROM AUTHOR]

The interest for sweet sorghum and sweet pearl millet use as potential feedstocks for bioethanol production has markedly increased in the last few years due to the high concentration in fermentable carbohydrates in their juice. The bottleneck of this production is the carbohydrate extraction process that needs to be optimized. The main objective of this study was therefore to determine the effect of operating conditions on water-soluble carbohydrate (WSC) extraction from the biomass of both species. For this purpose, two chopping modes of the biomass (coarse and fine) were investigated. Furthermore, the biomass was subjected to a second pressing after impregnation with water. In this context, the effects of four water:bagasse ratios (0.5, 1, 1.5, and 2) and three water temperatures (25, 45, and 65 °C) were evaluated. The initial biomass WSC concentration was 180 g kg−1 DM for sweet sorghum and 125.7 g kg−1 DM for sweet pearl millet. After the first pressing, these concentrations decreased by 63 and 56%, respectively. For the second pressing, the efficiency of WSC extraction was more influenced by the water:bagasse ratio than by the chopping mode and the water temperature. For an economic and energetic sustainable extraction process of carbohydrates, a coarse chopping, and a second pressing after impregnation with a water:bagasse ratio of 1 at 25 °C are therefore recommended to improve residual carbohydrate extraction. Under these conditions, the WSC extraction yields reached 83 and 78% for sweet sorghum and sweet pearl millet biomass, respectively. [ABSTRACT FROM AUTHOR]

Assessment and monitoring of soil organic matter (SOM) quality are important for determining and developing management practices that will enhance and maintain the productivity of agricultural soils. This requires routine analysis of multiple soil parameters, which can be time-consuming and expensive. Research has suggested that visible near infrared reflectance spectroscopy (VNIRS) may be used as a rapid and cost-efficient tool for SOM quality assessment. In this study, VNIRS (400-2498nm) was used for the first time to simultaneously predict microbial biomass nitrogen (MBN), water-extractable organic N (WEON), light fraction organic matter N (LFOMN), particulate organic matter N (POMN), soil total N (TN), soil organic carbon (SOC) and soil C/N ratio as soil SOM quality indicators in Chernozemic soils of western Canada. The soil samples (n=200) were collected at the 0-15cm depth from a crop rotation experiment conducted at 6 sites in 2010 and 2011. After removal of outliers (five samples) identified by principal components analysis (PCA), 75% of the sample set was randomly selected for calibration (n=146) and the remainder used for validation (n=49). Modified partial least squares regression with cross-validation was used to develop prediction models. The reliability of the models was assessed using the coefficient of determination in validation (R²V) and the ratio of standard deviation of the reference data in the validation set to the standard error of prediction (RPDV). The VNIRS predictions were considered reliable for LFOMN, POMN, TN, and SOC (R²V>0.80, RPDV>2.4), as well as for MBN (R²V=0.74, RPDV=1.93), but less reliable for WEON (R²V=0.67, RPDV=1.70) and soil C/N ratio (R²V=0.54, RPDV=1.45). This study showed that VNIRS has the potential as a non-destructive and cost-efficient tool for rapid determination of SOM quality indicators. [ABSTRACT FROM AUTHOR]

Near infrared reflectance spectroscopy (NIRS) holds promise for rapid assessment of soil total N and organic C contents, but its ability to predict soil N supply in soils with contrasting physio-chemical properties needs to be evaluated. The objectives of this study were to: (i) evaluate NIRS predictions of measured soil parameters (total N, organic C, and C/N ratio) and as an indirect indicator of soil N supply, namely corn (Zea mays L.) N uptake and (ii) assess the effect of sample set heterogeneity on NIRS predictions. Soil samples (n = 282 in the total set) were collected between 2000 and 2009 from 52 sites across four Canadian provinces and were allocated to fine- (≥ 350 g clay kg-1 n = 101) and coarse-textured subsets (<350 g clay kg-1 n = 181). Prediction models were developed using modified partial least squares regression. Prediction precision was assessed using the coefficient of determination (R²) and ratio of prediction to deviation (RPD = ratio of standard error of prediction corrected for bias to standard deviation of the reference data used in the validation). For the total set, predictions were reliable for total N, organic C and C/N ratio (0.7 ≤ R² ≤ 0.9, 1.75 ≤ RPD ≤ 3), and less reliable for soil N supply (R² < 0.7, RPD < 1.75). Prediction precision for total N, organic C, C/N ratio, and soil N supply increased with set homogeneity (i.e., better in the texture subsets than the total set), resulting in reliable predictions for soil N supply (RPD ≥ 2.00) in the texture subsets. This study demonstrated the possibility of developing reliable NIRS predictive models for total N, organic C, and C/N ratio for soils with contrasting physio- chemical properties, as well as reliable NIRS predictive models for soil N supply within homogeneous texture sets. [ABSTRACT FROM AUTHOR]

Increased atmospheric CO2 was shown to affect a variety of physiological processes in plants, including photosynthesis and growth with repercussions on crop yield and nutritive value. Perennial alfalfa ( Medicago sativa L.) is a sustainable crop with a deep root system, living in symbiosis with rhizobium for nitrogen (N) fixation. The objective of the project was to determine the combined effects of elevated CO2 and rhizobial strains on photosynthesis, growth, N fixation, and nutritive value of alfalfa, and on soil microflora. Alfalfa inoculated with two different strains of rhizobia ( Sinorhizobium meliloti strains A2 and NRG34) was grown 2 months at day/night temperatures of 22/17°C under either 400 (near ambient) or 800 (elevated) µmol mol−1 of CO2. The photosynthetic response of alfalfa to elevated CO2 differed according to the rhizobial strain. At the end of the experiment, elevated CO2 stimulated photosynthetic rates by 50% in plants associated with A2 but there was no significant increase in plants nodulated with NRG34. Nitrogenase activity (+38%) and shoot growth (+60%) were stimulated under 800 µmol mol−1 of CO2 for alfalfa inoculated with both strains. Root dry weight was significantly higher at 800 µmol mol−1 of CO2 only with strain A2. Fibre concentration decreased in response to elevated atmospheric CO2 in alfalfa inoculated with strain A2 resulting in plant material with greater nutritive value when inoculated with A2 compared to NRG34. In the soil, elevated CO2 increased the proportion of fungi in the microbial community while decreasing Gram− bacteria. For alfalfa inoculated with rhizobial strain A2, photosynthetic rates, nitrogenase activity, and growth were all stimulated by increased atmospheric CO2 compared to less consistently positive responses to elevated CO2 when inoculated with NRG34. Our results show that it is possible to identify rhizobial strains to improve plant performance under predicted future CO2 concentrations with no negative effect on nutritive value. [ABSTRACT FROM AUTHOR]

Alfalfa and its rhizobial symbiont are sensitive to salinity. We compared the physiological responses of alfalfa populations inoculated with a salt-tolerant rhizobium strain, exposed to five NaCl concentrations (0, 20, 40, 80, or 160 mM NaCl). Two initial cultivars, Halo (H-TS0) and Bridgeview (B-TS0), and two populations obtained after three cycles of recurrent selection for salt tolerance (H-TS3 and B-TS3) were compared. Biomass, relative water content, carbohydrates, and amino acids concentrations in leaves and nodules were measured. The higher yield of TS3-populations than initial cultivars under salt stress showed the effectiveness of our selection method to improve salinity tolerance. Higher relative root water content in TS3 populations suggests that root osmotic adjustment is one of the mechanisms of salt tolerance. Higher concentrations of sucrose, pinitol, and amino acid in leaves and nodules under salt stress contributed to the osmotic adjustment in alfalfa. Cultivars differed in their response to recurrent selection: under a 160 mM NaCl-stress, aromatic amino acids and branched-chain amino acids (BCAAs) increased in nodules of B-ST3 as compared with B-TS0, while these accumulations were not observed in H-TS3. BCAAs are known to control bacteroid development and their accumulation under severe stress could have contributed to the high nodulation of B-TS3. [ABSTRACT FROM AUTHOR]