Search results for "herb"
showing 10 items of 856 documents
Study of oligogalacturonides-triggered Nitric Oxide (NO) production provokes new questioning about the origin of NO biosynthesis in plants
2014
Addendum to: Rasul S, Dubreuil-Maurizi C, Lamotte O, Koen E, Poinssot B, Alcaraz G, et al. Nitric oxide production mediates oligogalacturonide-triggered immunity and resistance to Botrytis cinerea in Arabidopsis thaliana. Plant Cell Environ 2012; PMID:22394204; http://dx.doi. org/10.1111/j.1365-3040.2012.02505.x.; International audience; We investigated the production and function of nitric oxide (NO) in Arabidopsis thaliana leaf discs as well as whole plants elicited by oligogalacturonides (OGs). Using genetic, biochemical and pharmacological approaches, we provided evidence that OGs induced a Nitrate Reductase (NR)-dependent NO production together with an increased NR activity and NR tran…
Herbicidal potential of aqueous extracts from Melia azedarach L., Artemisia arborescens L., Rhus coriaria L. and Lantana camara L.
2017
In the search for new strategies for weed management in agricultural systems, a great interest is to use the plant extracts to replace or integrate, chemical weed control. Two experiments were done to test the effects of plant water extracts from Chinaberry (Melia azedarach L.), Tree Wormwood (Artemisia arborescens (Vaill.) L.), Sicilian Sumac (Rhus coriaria L.) and Lantana (Lantana camara L.) on seed germination of Rocket (Eruca sativa Mill.), Rapeseed (Brassica napus L.), Bladderflower (Araujia sericifera Brot.) and Psyllium (Plantago psyllium L). The water extracts (pure and 50% mixtures) from the donor species were applied on seeds of recipient plants. In second experiment in pots, thes…
Study of the performance of a resolution criterion to characterise complex chromatograms with unknowns or without standards
2017
The search for best conditions in liquid chromatography is routinely carried out with information provided by chemical standards. However, sometimes there are samples with insufficient knowledge about their chemical composition. In other cases, identities of the components are known, but there are no standards available, and in other cases the identities of peaks in chromatograms taken under different conditions are ambiguous. Most resolution criteria used to measure separation performance cannot be applied to these samples. In this work, a global resolution function valid for all situations was developed based on automatic measurements of peak prominences (area fraction exceeding the line …
First Report of Armillaria mellea on a Fern from Italy
2019
Several perennial species of rhizomatous herbaceous ferns are cultivated as ornamental foliage plants. During late summer 1999, in a garden at the foot of Mount Etna, eastern Sicily (Italy), we noted a fern hedge showing patches of withered or stunted plants. The fern was identified as Cyrtomium falcatum (L.f.) C. Presl. (=Polystichum falcatum (L.f.) Diels), a house holly fern or Japanese holly fern, which is an ornamental fern native to East and South Asia. Other woody plants in the immediate vicinity had died over the last few years, including apricot and cedar trees whose stumps had not been removed. A close examination of uprooted ferns revealed the presence of creamy white fan-shaped …
EVIDENCE OF NON-THERMAL X-RAY EMISSION FROM HH 80
2013
Protostellar jets appear at all stages of star formation when the accretion process is still at work. Jets travel at velocities of hundreds of km s -1, creating strong shocks when interacting with the interstellar medium. Several cases of jets have been detected in X-rays, typically showing soft emission. For the first time, we report evidence of hard X-ray emission possibly related to non-thermal processes not explained by previous models of the post-shock emission predicted in the jet/ambient interaction scenario. HH 80 is located at the south head of the jet associated with the massive protostar IRAS 18162-2048. It shows soft and hard X-ray emission in regions that are spatially separate…
X-ray emission from stellar jets by collision against high-density molecular clouds: an application to HH 248
2015
We investigate the plausibility of detecting X-ray emission from a stellar jet that impacts against a dense molecular cloud. This scenario may be usual for classical T Tauri stars with jets in dense star-forming complexes. We first model the impact of a jet against a dense cloud by 2D axisymmetric hydrodynamic simulations, exploring different configurations of the ambient environment. Then, we compare our results with XMM-Newton observations of the Herbig-Haro object HH 248, where extended X-ray emission aligned with the optical knots is detected at the edge of the nearby IC 434 cloud. Our simulations show that a jet can produce plasma with temperatures up to 10 MK, consistent with producti…
The Close T Tauri Binary System V4046 Sgr: Rotationally Modulated X-Ray Emission from Accretion Shocks
2012
We report initial results from a quasi-simultaneous X-ray/optical observing campaign targeting V4046 Sgr, a close, synchronous-rotating classical T Tauri star (CTTS) binary in which both components are actively accreting. V4046 Sgr is a strong X-ray source, with the X-rays mainly arising from high-density (n_e ~ 10^(11-12) cm^(-3)) plasma at temperatures of 3-4 MK. Our multiwavelength campaign aims to simultaneously constrain the properties of this X-ray emitting plasma, the large scale magnetic field, and the accretion geometry. In this paper, we present key results obtained via time-resolved X-ray grating spectra, gathered in a 360 ks XMM-Newton observation that covered 2.2 system rotatio…
Effects of radiation in accretion regions of classical T Tauri stars
2019
Models and observations indicate that the impact of matter accreting onto the surface of young stars produces regions at the base of accretion columns, in which optically thin and thick plasma components coexist. Thus an accurate description of these impacts requires to account for the effects of absorption and emission of radiation. We study the effects of radiation emerging from shock-heated plasma in impact regions on the structure of the pre-shock downfalling material. We investigate if a significant absorption of radiation occurs and if it leads to a pre-shock heating of the accreting gas. We developed a radiation hydrodynamics model describing an accretion column impacting onto the su…
CSI 2264: Simultaneous optical and X-ray variability in pre-main sequence stars. I. Time resolved X-ray spectral analysis during optical dips and acc…
2017
Pre-main sequence stars are variable sources. In stars with disks, this variability is related to the morphology of the inner circumstellar region (<0.1 AU) and that of the photosphere and corona, all impossible to be spatially resolved with present day techniques. This has been the main motivation for the Coordinated Synoptic Investigation of NGC 2264. In this paper, we focus on the stars with disks. We analyze the X-ray spectral properties extracted during optical bursts and dips in order to unveil the nature of these phenomena. We analyze simultaneous CoRoT and Chandra/ACIS-I observations to search for coherent optical and X-ray flux variability in stars with disks. Then, stars are an…
First Report of Southern Blight Caused by Sclerotium rolfsii on Hemp (Cannabis sativa) in Sicily and Southern Italy
2007
Hemp (Cannabis sativa L.), family Cannabaceae, is an annual herbaceous plant that is 1.5 to 4.0 m tall and native to the Caucasus Region, northern India, and Iran. It is cultivated in warm to temperate regions worldwide for its fiber, oil, and psychoactive substances. In Europe, commercial plantings have decreased from 52,872 ha in 1989 to 18,716 ha in 2005. Recently however, cultivation of hemp as a natural fiber species has been encouraged by European Union policy (2). During the summer of 2003, patches of dead plants were observed in test plots of 12 monoecious and dioecious hemp cultivars (Beniko, Epsylon 68, Felina 34, Ferimon, Fedora 17, Futura 75, Bialobrzeskie, Dioica 88, Fibranova…