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Medicago Sativa L. (medicago + sativa_l)
Selected AbstractsEffects of tractor wheeling on root morphology and yield of lucerne (Medicago sativa L.)GRASS & FORAGE SCIENCE, Issue 3 2008Summary The purpose of this study was to determine the effect of soil compaction on the herbage yield and root growth of lucerne (Medicago sativa L.). A field experiment was conducted on a silty loam Mollic Fluvisols soil in 2003,2006. Herbage yield and root morphology, in terms of root length density, mean root diameter, specific root length and distribution of dry matter (DM) in roots, were measured. Four compaction treatments were applied three times annually by tractor using the following number of passes: control without experimental traffic, two passes, four passes and six passes. The tractor traffic changed the physical properties of the soil by increasing bulk density and penetration resistance. Soil compaction also improved its water retention properties. These changes were associated with changes in root morphology and distribution of the DM in roots. Soil compaction resulted in higher proportions of the DM in roots, especially in the upper, 0,10 cm, soil horizon. Decreases in the root length density were observed in a root diameter range of 0·1,1·0 mm. It was also found that roots in a more compacted soil were significantly thicker. An effect of the root system of lucerne on soil compaction was observed. The root system of lucerne decreased the effects of soil compaction that had been recorded in the first and the second year of the experiment. An increase in the number of passes resulted in a decrease in the DM yield of herbage in the second and third harvests each year. [source] Effects of Water Shortage and Air Temperature on Seed Yield and Seed Performance of Lucerne (Medicago sativa L.) in a Mediterranean EnvironmentJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 6 2009A. J. Karamanos Abstract Seed production and performance of lucerne is characterized by fluctuating yields with often poor seed quality, and is dependent on environmental conditions, genetic characteristics and agronomic techniques applied during seed set, development, maturation and storage. A field experiment was carried out in two successive growing seasons at Kopais (southern Greece) to evaluate the effects of drought stress imposed by three irrigation treatments, and temperature during flowering and seed filling on lucerne seed yield and quality. Plant water status, expressed in terms of the water potential index (WPI), growth in leaf area and dry weight, seed yield and yield components, flowering and seed quality parameters were measured throughout the growing seasons. The adopted irrigation schemes produced a clear differentiation among treatments concerning their plant water status. Seed yield and leaf growth showed close positive correlations with WPI. An irrigation effect was also detected for the number of pods/plant, but not for the average weight of seeds/pod. Less negative values of WPI, and, especially, higher temperatures during flowering were also positively associated with a longer duration of flowering, as well as with higher total numbers of inflorescences. A very good description of the time course of seed germination was performed by fitting the Richards' function to the real data. By examining the germination parameters derived from this function it was found that final germination and germination rate were improved, while germination duration was shortened with more negative values of WPI. The effects of growing season and seeding period were occasionally equally or more important than irrigation effects. These results are also discussed in terms of their practical implications for seed producing lucerne crops. [source] Varietal Differences in Allelopathic Potential of AlfalfaJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2002Tran Dang Xuan Alfalfa (Medicago sativa L.) plants were found to contain water-soluble substances that inhibited the germination and seedling growth of alfalfa (Chung and Miller 1990, Agron. J. 87, 762,767). Tsuzuki et al. (1999, Rep. Kyushu Branch Crop Sci. Soc. Japan 65, 39,40) discovered allelochemicals in alfalfa plants that could have adverse effects on the growth of some lowland weeds. This study was conducted to investigate varietal differences in allelopathic potential in alfalfa plants. Eight common varieties of Japanese alfalfa (Medicago sativa L.), namely Batasu, Hisawakaba, Kitawakaba, Makiwakaba, Natsuwakaba, Lucerne, Tachiwakaba and Yuba, were grown by conventional methods in the Experimental Field of the Crop Science Laboratory, Faculty of Agriculture, Miyazaki University. Aqueous extracts of both fresh and dried material of alfalfa plants of all varieties significantly inhibited both germination and growth of lettuce (Lactuca sativa L.). Leachates from germinating seeds of almost all alfalfa varieties inhibited elongation of the radicle but produced a negligible increase in germination and only slightly inhibited elongation of the hypocotyl of lettuce plants. Results demonstrated that the degree of inhibition of germination and growth of lettuce varied with the variety of alfalfa. In particular, Lucerne was identified as having the strongest allelopathic potential of the varieties studied. The results suggested that the allelopathic potential of alfalfa might be relating to a gene. Varietätsunterschiede im allelopathischen Potential von Luzerne Luzerne (Medicago sativa L.)-Pflanzen weisen wasserlösliche Substanzen auf, die die Keimung und das Sämlingswachstum von Luzerne inhibieren. Es kann angenommen werden, daß Luzernepflanzen allelopathisch wirkende Verbindungen aufweisen, die das Wachstum von Unkrautpflanzen des Tieflands beeinträchtigen. Die Untersuchung wurde durchgeführt, um das Potential allelopathischer Sortenunterschiede bei Luzerne zu bestimmen. Acht im Anbau verwendete Luzernesorten , Batasu, Hisawakaba, Kitawakaba, Makiwakaba, Natsuwakaba, Lucerne, Tachiwakaba und Yuba , wurden nach konventionellen Verfahren auf dem Versuchsfeld des Pflanzenbauinstitutes der Fakultät der Miyazaki-Universität angebaut. Wässerige Extrakte von frischen und trockenen Luzernepflanzen hemmten bei allen Sorten signifikant die Keimung und das Wachstum von Salat (Lactuca sativa L.). Auszüge keimender Samen der meisten Luzernesorten inhibierten das Längenwachstum der Wurzel, hatten aber kaum Einfluß auf eine Förderung der Keimung und zeigten eine geringe Inhibierung des Längenwachstum des Hypokotyls von Salat. Die Ergebnisse zeigen, daß der Grad der Inhibierung der Keimung des Wachstums von Salat abhängig von den geprüften Luzernesorten ist. Lucerne hat das stärkste allelopathische Potential der Sorten. Die Ergebnisse lassen vermuten, daß das allelopathische Potential genetisch bedingt ist. [source] Glycosidases in soils as affected by cropping systemsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 6 2005Daniel E. Dodor Abstract Glycosidases are a group of soil enzymes that play a major role in degradation of carbohydrates. This study was conducted to assess the impact of crop rotation and N fertilization on the activities of ,- and ,-glucosidases and ,- and ,-galactosidases in plots of two long-term field experiments at the Clarion-Webster Research Center (CWRC) and Northeast Research Center (NERC) in Iowa. Surface-soil (0,15 cm) samples were taken in 1996 and 1997 in corn (Zeamays L.), soybean (Glycinemax (L.) Merr.), oats (Avenasativa L.), or meadow (alfalfa) (Medicago sativa L.) plots that received 0 or 180,kg N ha,1, applied as urea before corn, and an annual application of 20,kg P ha,1 and 56,kg K ha,1. Activities of the four glycosidases were significantly affected by crop rotations in both years at the two sites but not by nitrogen application. In general, higher activities were observed in plots under meadow or oat and the lowest in continuous corn (CWRC) and soybean (NERC). Four-year rotation showed the highest activity, followed by 2-year rotation and monocropping systems. Linear-regression analyses indicated that, in general, the activities of the glycosidases were significantly correlated with microbial-biomass C (r > 0.302, p , 0.05) and microbial-biomass N (r > 0.321, p , 0.05), organic-C (r > 0.332, p , 0.05) and organic-N (r > 0.399, p , 0.01) contents of the soils. Results of this work suggest that multicropping stimulated the activities of the glycosidases. The specific activities of the glycosidases in soils of the two sites studied, expressed as g p -nitrophenol released per,kg of organic C, differed among the four enzymes. The lowest values were obtained for ,-galactosidase and ,-glucosidase, followed by ,-galactosidase and ,-glucosidase. Glycosidasen in Böden unter dem Einfluss von Bewirtschaftungssystemen Glycosidasen stellen eine Gruppe von Bodenenzymen dar, welche eine entscheidende Rolle im Abbau von Kohlenhydraten spielen. Ziel dieser Untersuchungen war die Erfassung des Einflusses von Fruchtfolge und N-Düngung auf die Aktivitäten von ,- und ,-Glucosidasen und ,- und ,-Galactosidasen in zwei Langzeitfeldversuchen, dem Clarion-Webster-Versuchsfeld (CWRC) und dem Northeast-Versuchsfeld (NERC) in Iowa. In den Jahren 1996 und 1997 wurden Oberbodenproben (0,15 cm) von Parzellen unter Mais (Zeamays L.), Sojabohne (Glycine max (L.) Merr.), Hafer (Avena sativa L.) oder Luzerne (Medicago sativa L.) entnommen, welche vor Mais 0 oder 180,kg N ha,1 in Form von Harnstoff sowie jährliche Düngergaben in Höhe von 20,kg P ha,1 und 56,kg K ha,1 erhielten. Über zwei Jahre wurden die Aktivitäten der vier Glycosidasen in beiden Feldversuchen signifikant von der Bewirtschaftung beeinflusst, jedoch nicht von der N-Düngung. Im allgemeinen wurden höhere Enzymaktivitäten in Parzellen unter Luzerne oder Hafer festgestellt und die geringsten unter Maismonokultur (CWRC) bzw. Sojabohne (NERC). Vierjährige Fruchtfolgen zeigten die höchsten Aktivitäten, gefolgt von zweijährigen Fruchtfolgen und Monokulturen. Analysen mittels linearer Regression weisen auf eine Korrelation zwischen Glycosidaseaktivitäten und C (r > 0.332, p , 0.05) und N der mikrobiellen Biomasse (r > 0.321, p , 0.05) sowie den Gehalten an org. C (r > 0.332, p , 0.05) und N (r > 0.399, p , 0.01) hin. Die Ergebnisse dieser Untersuchungen deuten darauf hin, dass die Aktivitäten von Glycosidasen durch mehrjährige Fruchtfolgen stimuliert wurden. Die spezifischen Glycosidaseaktivitäten in den Böden der zwei Feldversuche, berechnet als freigesetztes p -Nitrophenol (g (kg org. C),1), variierten zwischen den vier Enzymen. Die geringsten Werte wurden für ,-Galactosidase und ,-Glucosidase festgestellt, gefolgt von ,-Galactosidase und ,-Glucosidase. [source] Proton release by N2 -fixing plant roots: A possible contribution to phytoremediation of calcareous sodic soilsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2003Manzoor Qadir Prof. Dr. Abstract With a world-wide occurrence on about 560 million hectares, sodic soils are characterized by the occurrence of excess sodium (Na+) to levels that can adversely affect crop growth and yield. Amelioration of such soils needs a source of calcium (Ca2+) to replace excess Na+ from the cation exchange sites. In addition, adequate levels of Ca2+ in ameliorated soils play a vital role in improving the structural and functional integrity of plant cell walls and membranes. As a low-cost and environmentally feasible strategy, phytoremediation of sodic soils , a plant-based amelioration , has gained increasing interest among scientists and farmers in recent years. Enhanced CO2 partial pressure (PCO2) in the root zone is considered as the principal mechanism contributing to phytoremediation of sodic soils. Aqueous CO2 produces protons (H+) and bicarbonate (HCO3 - ). In a subsequent reaction, H+ reacts with native soil calcite (CaCO3) to provide Ca2+ for Na+ Ca2+ exchange at the cation exchange sites. Another source of H+ may occur in such soils if cropped with N2 -fixing plant species because plants capable of fixing N2 release H+ in the root zone. In a lysimeter experiment on a calcareous sodic soil (pHs = 7.4, electrical conductivity of soil saturated paste extract (ECe) = 3.1 dS m -1, sodium adsorption ratio (SAR) = 28.4, exchangeable sodium percentage (ESP) = 27.6, CaCO3 = 50 g kg -1), we investigated the phytoremediation ability of alfalfa (Medicago sativa L.). There were two cropped treatments: Alfalfa relying on N2 fixation and alfalfa receiving NH4NO3 as mineral N source, respectively. Other treatments were non-cropped, including a control (without an amendment or crop), and soil application of gypsum or sulfuric acid. After two months of cropping, all lysimeters were leached by maintaining a water content at 130% waterholding capacity of the soil after every 24±1 h. The treatment efficiency for Na+ removal in drainage water was in the order: sulfuric acid > gypsum = N2 -fixing alfalfa > NH4NO3-fed alfalfa > control. Both the alfalfa treatments produced statistically similar root and shoot biomass. We attribute better Na+ removal by the N2 -fixing alfalfa treatment to an additional source of H+ in the rhizosphere, which helped to dissolve additional CaCO3 and soil sodicity amelioration. Protonenabgabe durch N2 -fixierende Pflanzenwurzeln: ein möglicher Beitrag zur Phytomelioration von kalkreichen Natriumböden Bei einem weltweiten Vorkommen auf etwa 560 Millionen Hektar sind Natriumböden durch einen Überschuss an Natrium (Na+) gekennzeichnet, der das Wachstum und den Ertrag von Kulturpflanzenbeständen nachteilig beeinflussen kann. Die Melioration solcher Böden erfordert Calcium (Ca2+), um überschüssiges Na+ von Kationen-Austauscherplätzen zu verdrängen. Außerdem spielt Ca2+ eine wichtige Rolle bei der Verbesserung der strukturellen und funktionellen Integrität pflanzlicher Zellwände und Membranen. Als kostengünstige und umweltfreundliche Strategie hat die Phytomelioration von Natriumböden , eine auf Pflanzen beruhende Melioration , in den letzten Jahren zunehmendes Interesse bei Wissenschaftlern und Landwirten gefunden. Ein erhöhter CO2 -Partialdruck (PCO2) in der Rhizosphäre wird als hauptsächlicher Mechanismus angesehen, der zur Phytomelioration von Natriumböden beiträgt. In Wasser gelöst, erzeugt CO2 Protonen (H+) und Bikarbonate (HCO3 - ). Anschließend reagiert H+ mit nativem Calcit (CaCO3), wobei sich Ca2+ löst und Na+ von Austauscherplätzen verdrängt. Eine weitere H+ -Quelle könnte die H+ -Abgabe von Wurzeln N2 -fixierender Pflanzen sein, da diese in der Lage sind, H+ in die Rhizosphäre abzugeben. In einem Lysimeterversuch mit einem kalkreichen Natriumboden (pHs = 7, 4; ECe = 3, 1 dS m -1; SAR = 28, 4; ESP = 27, 6; CaCO3 = 50 g kg -1) wurde die Möglichkeit einer Phytomelioration mit N2 -fixierender Luzerne (Medicago sativa L.) im Vergleich zu einer mit mineralischem N ernährten Luzerne (NH4NO3) untersucht. In weiteren Varianten (Applikation von Gips bzw. Schwefelsäure) wurde die chemische Melioration einer nicht behandelten Kontrolle gegenübergestellt. Beide Ernährungsformen führten zu statistisch ähnlicher Wurzelund Sprossmasse der Luzerne. Nach zweimonatigem Pflanzenwachstum erfolgte alle 24±1 h eine Dränung der Lysimeter durch Zugabe einer Wassermenge von 130% der maximalen Wasserkapazität zum Boden. Hinsichtlich der Effizienz, Na+ über Auswaschung aus dem Boden zu entfernen, zeigte sich folgende Reihenfolge: Schwefelsäure > Gips = N2 -fixierende Luzerne > NH4NO3 -ernährte Luzerne > Kontrolle. Wir führen das bessere Meliorationsergebnis in der Variante der N2 -fixierenden Luzerne auf eine zusätzliche H+ -Quelle in der Rhizosphäre zurück, die zur Lösung von zusätzlichem CaCO3 beitrug. [source] Effect of fibrolytic enzymes and an inoculant on in vitro degradability and gas production of low-dry matter alfalfa silageJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2008Lazar K Kozelov Abstract BACKGROUND: The objective of this study was to investigate the effect of polysaccharide-degrading enzymes (a cellulase and a xylanase) alone or in a combination with a bacterial inoculant on fermentation parameters and in vitro degradability and gas production of low-dry matter (DM) alfalfa silage. First cut alfalfa (Medicago sativa L.), harvested at about 5% bloom stage [260 g kg,1 dry matter (DM)] was ensiled in laboratory-scale silos without preservatives or preserved with formic acid, a cellulase (Cell), a xylanase, a cellulose/xylanase enzyme combination (Cell/Xyl), a lactic acid bacteria-based inoculant (Inoc), and a mix of Inoc and Cell (Inoc/Cell). Triplicate silos were opened on days 1, 3, 7, 15 and 60. RESULTS: Silage pH and ammonia N and total free amino acids concentrations were the lowest (P < 0.05) for the formic acid silage. Inoc and Inoc/Cell produced the highest (P < 0.05) lactate concentration in the 60-day silage. In vitro degradability of silage DM was not affected (P = 0.998) by treatment, but amylase-treated neutral detergent fiber degradability was increased (P < 0.05) by formic acid. Compared with the control (51.3 mL 100 mg,1 silage DM), all treatments except Cell/Xyl increased (P < 0.001) the 24 h cumulative gas production. CONCLUSIONS: Overall, enzyme and lactic acid bacteria-based preparations had minor effects on silage fermentation in this experiment. The increased cumulative gas production indicates some preservation or liberation of fermentable organic matter with most treatments tested. It is not clear, however, to what extent this effect would impact silage ruminal degradability in vivo. Copyright © 2008 Society of Chemical Industry [source] Phytoestrogen content of alfalfa cultivars grown in eastern CanadaJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 5 2006Philippe Seguin Abstract Alfalfa (Medicago sativa L.) contains several phytoestrogens that may have health-promoting effects in humans. In this study, the concentrations of three phytoestrogens (apigenin, coumestrol, and luteolin) of ten field-grown alfalfa cultivars were determined in the seeding and post-seeding year at two sites in Sainte-Anne-de-Bellevue, QC, Canada. Herbage and phytoestrogen yield per hectare were concurrently determined. Differences between cultivars were only observed for apigenin concentration and yield and coumestrol yield. There was a 37% variation between cultivars in apigenin concentration. Site-by-harvest interactions and harvest main effects were observed for the concentration and yield of all three phytoestrogens. There was a 2- and 2.5-fold variation in coumestrol and luteolin concentrations, respectively, between harvests of both sites. Coumestrol concentration was lower in harvests of the seeding than of the post-seeding year. Luteolin concentration fluctuated during the five harvests at one site, but was greater in the seeding than in the post-seeding year at the other site. There was a 5.4-fold variation in apigenin concentration between harvests of both sites, concentrations being lower in the seeding (avg. 173 µg g,1 DM) than in the post-seeding year. Results suggest that choice of cultivars have limited impact on alfalfa phytoestrogen concentration, which, however, greatly differ between harvests and sites. Copyright © 2006 Society of Chemical Industry [source] Sodium removal from a calcareous saline,sodic soil through leaching and plant uptake during phytoremediationLAND DEGRADATION AND DEVELOPMENT, Issue 3 2003M. Qadir Abstract Saline,sodic and sodic soils are characterized by the occurrence of sodium (Na+) to levels that can adversely affect several soil properties and growth of most crops. As a potential substitute of cost-intensive chemical amelioration, phytoremediation of such soils has emerged as an efficient and low-cost strategy. This plant-assisted amelioration involves cultivation of certain plant species that can withstand ambient soil salinity and sodicity levels. It relies on enhanced dissolution of native calcite within the root zone to provide adequate Ca2+ for the Na+Ca2+ exchange at the cation exchange sites. There is a lack of information for the Na+ balance in terms of removal from saline,sodic soils through plant uptake and leaching during the phytoremediation process. We carried out a lysimeter experiment on a calcareous saline,sodic soil [pH of saturated soil paste (pHs),=,7.2, electrical conductivity of the saturated paste extract (ECe),=,4.9,dS,m,1, sodium adsorption ratio (SAR),=,15.9, CaCO3,=,50,g,kg,1]. There were three treatments: (1) control (without application of a chemical amendment or crop cultivation), (2) soil application of gypsum according to the gypsum requirement of the soil and (3) planting of alfalfa (Medicago sativa L.) as a phytoremediation crop. The efficiency of treatments for soluble salt and Na+ removal from the soil was in the order: gypsum,,,alfalfa,>,control. In the phytoremediation treatment, the amount of Na+ removed from the soil through leaching was found to be the principal cause of reduction in salinity and sodicity. Copyright © 2003 John Wiley & Sons, Ltd. [source] How mitochondrial DNA diversity can help to understand the dynamics of wild-cultivated complexes.MOLECULAR ECOLOGY, Issue 12 2001The case of Medicago sativa in Spain Abstract In order to clarify the relationships (genetic exchange and shared ancestry) between natural and cultivated populations of alfalfa (Medicago sativa L.) in Spain, we investigated the patterns of mitochondrial DNA variation (characterized through restriction fragment length polymorphism) for 248 individuals in seven natural and six cultivated populations of this species. Mitochondrial variation was evidenced in both natural and cultivated populations of M. sativa. Among the seven mitotypes idengified in the species, two were specific of the natural populations, a result attesting the fact that the Spanish wild form of M. sativa is an original genetic pool compared to the cultivated one. Other mitotypes were observed in both natural and cultivated populations, suggesting the occurrence of gene flow through seeds from cultivated towards natural populations. Comparisons with previously gathered nuclear and phenotypic data give insights into the different evolutionary forces acting on the different kinds of Spanish natural populations examined so far. [source] Multi-site genetic modulation of monolignol biosynthesis suggests new routes for formation of syringyl lignin and wall-bound ferulic acid in alfalfa (Medicago sativa L.)THE PLANT JOURNAL, Issue 1 2006Fang Chen Summary Genes encoding seven enzymes of the monolignol pathway were independently downregulated in alfalfa (Medicago sativa) using antisense and/or RNA interference. In each case, total flux into lignin was reduced, with the largest effects arising from the downregulation of earlier enzymes in the pathway. The downregulation of l -phenylalanine ammonia-lyase, 4-coumarate 3-hydroxylase, hydroxycinnamoyl CoA quinate/shikimate hydroxycinnamoyl transferase, ferulate 5-hydroxylase or caffeic acid 3- O -methyltransferase resulted in compositional changes in lignin and wall-bound hydroxycinnamic acids consistent with the current models of the monolignol pathway. However, downregulating caffeoyl CoA 3- O -methyltransferase neither reduced syringyl (S) lignin units nor wall-bound ferulate, inconsistent with a role for this enzyme in 3- O -methylation ofS monolignol precursors and hydroxycinnamic acids. Paradoxically, lignin composition differed in plants downregulated in either cinnamate 4-hydroxylase or phenylalanine ammonia-lyase. No changes in the levels of acylated flavonoids were observed in the various transgenic lines. The current model for monolignol and ferulate biosynthesis appears to be an over-simplification, at least in alfalfa, and additional enzymes may be needed for the 3- O -methylation reactions of S lignin and ferulate biosynthesis. [source] Evaluating combined land conservation benefits from perennial pasture: lucerne (Medicago sativa L.) for management of dryland salinity and herbicide resistance in Western Australia,AUSTRALIAN JOURNAL OF AGRICULTURAL & RESOURCE ECONOMICS, Issue 2 2009Graeme J. Doole The inclusion of perennial pasture phases in cropping rotations has been widely promoted throughout Australia for reducing the incidence of dryland salinity. To a lesser extent, they have also been promoted to enhance the management of herbicide-resistant weeds. No previous economic analysis of perennial pasture has considered both of these benefits. This study combines a dynamic linear programming model to estimate the magnitude of salinity-related benefits and a complex simulation model to assess the economics of herbicide-resistance management. We present a case study of the perennial pasture lucerne (Medicago sativa L.) in the Wheatbelt of Western Australia, where the weed annual ryegrass (Lolium rigidum Gaudin) is resistant to multiple herbicide groups. Sequences incorporating lucerne are the most profitable land use at the standard set of parameter values if (i) annual ryegrass is resistant to all selective herbicides, (ii) the water table is so shallow (approximately < 3.5 m deep) that frequent rotation with perennials is required to avert soil salinisation, (iii) sheep production is highly profitable, or (iv) there is a combination of less extreme cases. The value of perennial pasture is sufficient under these circumstances to overcome its high establishment cost and the displacement of multiple years of crop. Consideration of dryland salinity and herbicide resistance are about equally important in evaluating the economics of lucerne; neither should be neglected. [source] |