Search results for "Vegetal Biology"

L'imagerie multispectrale embarquée pour caractériser la croissance et l'état sanitaire du feuillage de la vigne

2015

Multispectral imaging systems are widely used in remote sensing and applied to viticulture context for the canopy characterization. This technique is not used in proximal sensing, to characterize vineyard foliage. Yet the results of field tests led in fixed position have revealed its capacity to estimate the leaf area. The aim of this project is to assess the suitable of a multispectral imaging system as an embedded sensor for vine foliage characterization. To this end, a multispectral camera acquiring visible and near-infrared images and a Greenseeker RT-100 apparatus providing an NDVI (Normalized Difference Vegetation Index), were installed on a track laying tractor. It was equipped with …

Roughness evaluation of vine leaf by image processing

2013

International audience; The study of leaf surface roughness is very important in the domain of precision spraying. It is one of the parameters that allow to reduce costs and losses of phytosanitary prod- ucts and to improve the spray accuracy. Moreover, the leaf roughness is related to adhesion mechanisms of liquid on a surface. It can be used to define leaf nature surface (hy- drophilic/hydrophobic). The main goal of this study is thus to estimate and to follow the evolution of leaf roughness using image processing and computer vision. The develop- ment and application of computer vision for measurement of surface leaf roughness using artificial neural networks will be described. The syste…

Aptitude d'une chaîne de modélisation hydroclimatique à évaluer les impacts de changements d'occupation du sol à l'échelle de 3 bassins versants bour…

2017

National audience; En réponse à la dégradation qualitative de la ressource en eau, les politiques publiques ont mis en place de plus en plus de mesures agro-environnementales (Bouleau and Richard, 2008). L'amélioration constante des modèles agronomiques et/ou hydrologiques a permis d'atteindre une reproduction cohérente des interactions sol/plante/atmosphère et ainsi de prévoir les impacts de ces mesures agro-environnementales. Le modèle SWAT permet de prendre en compte des pratiques agricoles détaillées et d'en déterminer les impacts sur la ressource en eau (Xie et al., 2015). En France, des projets tels que ECCOTER (Vernier and Rousset, 2014) ont montré l'efficacité du modèle SWAT pour te…

Functional ecology for evaluating and predicting the aptitude of permanent grassland to provide services

2013

National audience; Applying the principles of functional ecology helps better predict the services which can be provided by permanent grassland. Farming practices and environmental characteristics influence the functional composition of grassland. Functional plant types have a generic effect on forage services which can be assessed. 13 types of grassland composed of distinct functional types were defined based on 1,283 sample grassland fields located on 8 sites. This approach was validated by checking 8 Ellenberg indicator values (used to evaluate environmental characteristics and farming practices) against climatic data and descriptive data for farming practices. The interest of a function…

Seasonal fluctuations and long-term persistence of pathogenic populations of Agrobacterium spp. in soils.

2002

ABSTRACT Short- and long-term persistence of pathogenic (i.e., tumor forming) agrobacteria in soil was investigated in six nursery plots with a history of high crown gall incidence. No pathogenic Agrobacterium strains were isolated in soil samples taken in fall and winter in any plots, but such strains were isolated from both bulk soils and weed rhizospheres (over 0.5 × 10 5 pathogenic CFU/g of bulk soil or rhizosphere) in three out of six plots in spring and summer. PCR amplifications of a vir sequence from DNA extracted from soil confirmed the presence of Ti plasmids in summer and their absence in fall and winter. The results indicate that strains that harbor a Ti plasmid had an unforesee…

Short term adaptive response of symbiotic N2 fixation in pea to root pruning of half the root system, linked to the availability of carbon assimilates

2014

Symbiotic N fixation of legumes is very sensitive to environmental stresses, like pea pests damaging nodulated roots. However, the impact on their N uptake capacity and plant growth has not been studied so far.We analyzed the adaptive response symbiotic N2 fixation and plant growth of pea wild type Frisson and hypernodulating mutants P64, P118 and P121 mutated respectively on genes SYM28, SYM29 and NOD3 to root pruning of half the root system at the end of the vegetative stage. The adaptive responses of pea: cv. Frisson and 3 of its hypernodulating mutants were compared under varying carbon supplies from photosynthesis.At 380 ppm, mutant P118 showed the lowest decrease of the specific activ…

Acyl-homoserine lactone production is more common among plant-associated Pseudomonas spp. than among soilborne Pseudomonas spp.

2001

ABSTRACT A total of 137 soilborne and plant-associated bacterial strains belonging to different Pseudomonas species were tested for their ability to synthesize N -acyl-homoserine lactones (NAHL). Fifty-four strains synthesized NAHL. Interestingly, NAHL production appears to be more common among plant-associated than among soilborne Pseudomonas spp. Indeed, 40% of the analyzed Pseudomonas syringae strains produced NAHL which were identified most often as the short-chain NAHL, N -hexanoyl- l -homoserine lactone, N -(3-oxo-hexanoyl)-homoserine lactone, and N -(3-oxo-octanoyl)- l -homoserine lactone (no absolute correlation between genomospecies of P. syringae and their ability to produce NAHL …

Nitric oxide signaling in plants: cross-talk with Ca2+, protein kinases and reactive oxygen species

2009

Over-expression of the epidermis-specific HD-ZIP IV transcription factor OCL1 in maize identifies target genes involved in lipid metabolism and cutic…

2010

International audience

Chemical and biological study of saponins isolated from three malagasy species belonging to Caryophyllaceae, Pittosporaceae and Solanaceae families

2013

This thesis was carried out in the Laboratory of Pharmacognosy, in the Pharmacy section of the University of Burgundy. The principal theme of this laboratory is the research of natural compounds from tropical biodiversity, mainly saponins. In this context, the study of Malagasy plants, Polycarpaea corymbosa Lamk. (CARYOPHYLLACEAE), Pittosporum verticillatum Bojer subsp. verticillatum (PITTOSPORACEAE), Solanum incanum L. and S. heteracanthum Dunal. (SOLANACEAE) led to the isolation of fifteen natural glycosides by column chromatography, medium pressure liquid chromatography, flash chromatography, and vacuum liquid chromatography. The structures were elucidated mainly by the use of spectrosco…