scholarly journals Nitrogen Fixation, Nodule Development, and Vegetative Regrowth of Alfalfa (Medicago sativa L.) following Harvest

1979 ◽  
Vol 64 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Carroll P. Vance ◽  
Gary H. Heichel ◽  
Donald K. Barnes ◽  
Jeff W. Bryan ◽  
Lois E. Johnson
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Nodule Development ◽  
Medicago Sativa L

EFFECTS OF INITIAL HARVEST DATE ON PRODUCTIVITY AND PERSISTENCE OF ALFALFA AND BROMEGRASS

1972 ◽  
Vol 52 (5) ◽  
pp. 801-804 ◽  
Author(s):  
J. D. McELGUNN ◽  
D. H. HEINRICHS ◽  
R. ASHFORD
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Taraxacum Officinale ◽  
Bromus Inermis ◽  
Harvest Date ◽  
Mixed Stands ◽  
Medicago Sativa L ◽  
Made In

Alfalfa (Medicago sativa L.), bromegrass (Bromus inermis Leyss.), and a mixture of the two were grown on irrigated land and subjected to six defoliation schedules in which the initial cutting date varied in time. Delaying the initial defoliation until mid-June resulted in greatest seasonal yield even though the last cutting in this schedule was made in the 1st week of September, usually considered somewhat late for cutting in Saskatchewan. Nitrogen at the rate of 112 kg/ha doubled the yield of bromegrass but did not increase the yield of the alfalfa–bromegrass mixture, indicating that nitrogen fixation was adequate for the crop. Alfalfa and the alfalfa–bromegrass mixtures yielded about 50% more forage than the N-fertilized bromegrass and three times as much as unfertilized bromegrass. At the end of the experiment, dandelions (Taraxacum officinale Weber) had invaded pure stands of alfalfa but not mixed stands of alfalfa and bromegrass.

scholarly journals Autumn establishment of lucerne (Medicago sativa L.) inoculated with four different carriers of Ensifer meliloti at four sowing dates

2013 ◽  
pp. 137-143
Author(s):  
D.B.S. Black ◽  
D.J. Moot
Keyword(s):  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Biological Nitrogen Fixation ◽  
Sowing Date ◽  
Sowing Dates ◽  
Treated Seed ◽  
Loam Soil ◽  
Medicago Sativa L ◽  
Biological Nitrogen ◽  
Coated Seed

The effects of autumn sowing dates (26 January 2012, 21 February 2012, 15 March 2012, 3 April 2012) and inoculant carriers (ALOSCA®, coated seed, Nodulator® and peat slurry) on lucerne (Medicago sativa L.) establishment and yield were studied at Lincoln University on a variable Templeton silt loam soil. For the 2012/13 regrowth season the January (14.7 t/ha) sowing date yielded more dry matter (DM) than the March (11.2 t/ha) and April (7.3 t/ha) sowing dates, and February (13.2 t/ha) was intermediate. All four inoculation carriers resulted in increased DM and nitrogen (N) yields compared with the bare seed control. A comparison of the peat inoculated and bare seed treatments indicated an extra 335 kg N/ha was removed in herbage from the inoculated treatments. Results highlight the importance of rhizobia, biological nitrogen fixation, and seed inoculation when sowing lucerne into soil with no paddock history of lucerne. Keywords: alfalfa, ALOSCA®, bare seed, biological nitrogen fixation, coated seed Nodulator®, peat slurry treated seed, rhizobia.

scholarly journals Characterization of theSinorhizobium melilotiHslUV and ClpXP Protease Systems in Free-Living and Symbiotic States

2019 ◽  
Vol 201 (7) ◽  
Author(s):  
Aaron J. Ogden ◽  
Jacqueline M. McAleer ◽  
Michael L. Kahn
Keyword(s):  
Quality Control ◽  
Nitrogen Fixation ◽  
Medicago Sativa ◽  
Soil Bacteria ◽  
Symbiotic Nitrogen Fixation ◽  
Nodule Development ◽  
Stress Adaptation ◽  
Free Living ◽  
Content Type ◽  
Metabolic Remodeling

ABSTRACTSymbiotic nitrogen fixation (SNF) in the interaction between the soil bacteriaSinorhizobium melilotiand legume plantMedicago sativais carried out in specialized root organs called nodules. During nodule development, each symbiont must drastically alter their proteins, transcripts, and metabolites in order to support nitrogen fixation. Moreover, bacteria within the nodules are under stress, including challenges by plant antimicrobial peptides, low pH, limited oxygen availability, and strongly reducing conditions, all of which challenge proteome integrity.S. melilotistress adaptation, proteome remodeling, and quality control are controlled in part by the large oligomeric protease complexes HslUV and ClpXP1. To improve understanding of the roles ofS. melilotiHslUV and ClpXP1 under free-living conditions and in symbiosis withM. sativa, we generated ΔhslU, ΔhslV, ΔhslUV, and ΔclpP1knockout mutants. The shoot dry weight ofM. sativaplants inoculated with each deletion mutant was significantly reduced, suggesting a role in symbiosis. Further, slower free-living growth of the ΔhslUVand ΔclpP1mutants suggests that HslUV and ClpP1 were involved in adapting to heat stress, the while ΔhslUand ΔclpP1mutants were sensitive to kanamycin. All deletion mutants produced less exopolysaccharide and succinoglycan, as shown by replicate spot plating and calcofluor binding. We also generated endogenous C-terminal enhanced green fluorescent protein (eGFP) fusions to HslU, HslV, ClpX, and ClpP1 inS. meliloti. Using anti-eGFP antibodies, native coimmunoprecipitation experiments with proteins from free-living and nodule tissues were performed and analyzed by mass spectrometry. The results suggest that HslUV and ClpXP were closely associated with ribosomal and proteome quality control proteins, and they identified several novel putative protein-protein interactions.IMPORTANCESymbiotic nitrogen fixation (SNF) is the primary means by which biologically available nitrogen enters the biosphere, and it is therefore a critical component of the global nitrogen cycle and modern agriculture. SNF is the result of highly coordinated interactions between legume plants and soil bacteria collectively referred to as rhizobia, e.g.,Medicago sativaandS. meliloti, respectively. Accomplishing SNF requires significant proteome changes in both organisms to create a microaerobic environment suitable for high-level bacterial nitrogenase activity. The bacterial protease systems HslUV and ClpXP are important in proteome quality control, in metabolic remodeling, and in adapting to stress. This work shows thatS. melilotiHslUV and ClpXP are involved in SNF, in exopolysaccharide production, and in free-living stress adaptation.

Estimación de biomasa aérea de forrajes de invierno bajo riego a través de un dron

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Francisco Gavi Reyes ◽  
César Botello-Aguillón ◽  
Leonardo Tijerina-Chávez ◽  
Arturo Galvis-Spíndola ◽  
Rodrigo Roblero-Hidalgo
Keyword(s):  
Medicago Sativa ◽  
Avena Sativa ◽  
Medicago Sativa L

E Objetivo: Desarrollar un procedimiento para estimar biomasa con imágenes digitales captadas desde un dron y modelación 3D (ID-Dron-3D) aplicable en alfalfa (Medicago sativa L.) y avena forrajera (Avena sativa L.). Diseño/metodología/aproximación: Con una cámara digital acoplada al dron se obtuvieron imágenes antes de la cosecha de los cultivos, que fueron procesadas con software para luego estimar volumen de biomasa. En cada cultivo se midió altura de la planta y área cosechada, volumen aparente y real de biomasa, y peso de biomasa fresca y seca. Resultados: Con base en el análisis de regresión se obtuvieron modelos lineales a una p<0.05 para predecir: biomasa fresca en avena (R2=0.70) y alfalfa (R2 =0.47); y biomasa seca en avena (R2=0.78) y en alfalfa (R2=0.31) mediante ID-Dron-3D. Limitaciones del estudio/implicaciones: Considerando las R2 de los modelos obtenidos, los resultados en la avena forrajera fueron mejores, respecto a los detectados en alfalfa, lo cual se puede deber a la mayor variabilidad de la cobertura vegetal, ya que, en algunas unidades de muestreo, las plantas de alfalfa no cubrían completamente el suelo. Hallazgos/conclusiones: El rendimiento de biomasa fresca y seca de ambos cultivos se correlacionó significativamente con su respectivo volumen aparente estimado con imágenes digitales tomadas desde un dron y su procesamiento 3D (ID-Dron-3D).

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