Search results for "classification"
showing 10 items of 29475 documents
Metabolism of chlortoluron in tolerant species: possible role of cytochrome p-450 mono-oxygenases
1988
Summary Pathways of chlortoluron metabolism were compared in excised leaves of four tolerant species, namely wheat (Triticum aestivum var Clement), Bromus sterilis, Galium aparine and Veronica persica. The herbicide was principally detoxified by hydroxylation of the ring methyl in wheat and by N-dealkylation in Veronica persica. Both pathways were involved in Bromus sterilis and Galium aparine. Kinetic study of the degradation showed that capacity to form non-toxic conjugates could, at least partially, explain the tolerance of these species to chlortoluron. In plants treated with 1-aminobenzotriazole, a cytochrome P-450 enzyme inactivator, N-dealkylation of chlortoluron was little or not af…
Isolation and identification of 4,6,8-trimethyl-7,9-undecadien-5-ol, a female-specific compound, in tergal gland secretion ofCryptocercus punctulatus…
1991
International audience; The secretion of the tergal glands of Cryptocercus punctulatus consists of a complex mixture of 27 compounds. Of this mixture, only one compound (compound B) is specific for females. By dissecting 200 tergal glands, 50 µg of pure compound B was collected by preparative GC; it was identified as (Z, E-4,6,8-trimethyl-7,9-undecadien-5-oI. Its functions as well as its absolute configuration still have to be determined.
Can the large ecological amplitude of Ambrosia artemisiifolia explain its invasive success in France?
2008
International audience; In order to understand the successful spread of Ambrosia artemisiifolia in France, the variability of colonised habitat by this species was studied at 48 locations, from its central to peripheral area of distribution. Each site was characterised by a vegetation survey, a description of the A. artemisiifolia population and a soil analysis. Differences in the number of species, Shannon diversity index, evenness index and plant life form spectra were compared among the sites. A total of 276 species occurring along with A. artemisiifolia was observed. Therophytes and hemicryptophytes represented more than 80% of all the species. The two most frequent species occurring al…
Looking for Hidden Enemies of Metabarcoding: Species Composition, Habitat and Management Can Strongly Influence DNA Extraction while Examining Grassl…
2021
Despite the raising preoccupation, the critical question of how the plant community is composed belowground still remains unresolved, particularly for the conservation priority types of vegetation. The usefulness of metabarcoding analysis of the belowground parts of the plant community is subjected to a considerable bias, that often impedes detection of all species in a sample due to insufficient DNA quality or quantity. In the presented study we have attempted to find environmental factors that determine the amount and quality of DNA extracted from total plant tissue from above- and belowground samples (1,000 and 10,000 cm2). We analyzed the influence of land use intensity, soil properties…
Nested core collections maximizing genetic diversity in Arabidopsis thaliana.
2004
Summary The successful exploitation of natural genetic diversity requires a basic knowledge of the extent of the variation present in a species. To study natural variation in Arabidopsis thaliana, we defined nested core collections maximizing the diversity present among a worldwide set of 265 accessions. The core collections were generated based on DNA sequence data from a limited number of fragments evenly distributed in the genome and were shown to successfully capture the molecular diversity in other loci as well as the morphological diversity. The core collections are available to the scientific community and thus provide an important resource for the study of genetic variation and its …
Degradation of sexual reproduction in Veronica filiformis after introduction to Europe
2011
Abstract Background Baker’s law predicts that self-incompatible plant species are generally poor colonizers because their mating system requires a high diversity of genetically differentiated individuals and thus self-compatibility should develop after long-distance dispersal. However, cases like the introduction of the self-incompatible Veronica filiformis (Plantaginaceae) to Europe constitute an often overlooked alternative to this rule. This species was introduced from subalpine areas of the Pontic-Caucasian Mountains and colonized many parts of Central and Western Europe in the last century, apparently without producing seeds. To investigate the consequences of the absence of sexual rep…
The dominance of the herbicide resistance cost in several Arabidopsis thaliana mutant lines
2004
Abstract Resistance evolution depends upon the balance between advantage and disadvantage (cost) conferred in treated and untreated areas. By analyzing morphological characters and simple fitness components, the cost associated with each of eight herbicide resistance alleles (acetolactate synthase, cellulose synthase, and auxin-induced target genes) was studied in the model plant Arabidopsis thaliana. The use of allele-specific PCR to discriminate between heterozygous and homozygous plants was used to provide insights into the dominance of the resistance cost, a parameter rarely described. Morphological characters appear more sensitive than fitness (seed production) because 6 vs. 4 differen…
Phytochemical profiles, phototoxic and antioxidant properties of eleven Hypericum species - A comparative study
2018
Hypericum is one out of the nine genera belonging to the botanical family Clusiaceae Lindl (syn. Hypericaceae Juss.; APG III, 2009). The genus contains 484 species spread worldwide, one of which, Hypericum perforatum, is largely used in folk medicine. The aim of this study was to evaluate the chemical composition, along with the antioxidant and phototoxic activity, of 11 Hypericum species grown in Sicily (H. perforatum L., H. aegypticum L., H. androsaemum L., H. calycinum L., H. hircinum L., H. hirsutum L., H. montanum L., H. patulum Thunb., H. perfoliatum L., H. pubescens Boiss., H. tetrapterum Fr.). Samples of flowering tops collected from these Hypericum species were extracted and analys…
The Application of a Plant Biostimulant Based on Seaweed and Yeast Extract Improved Tomato Fruit Development and Quality
2020
Plant biostimulants are under investigation as innovative products to improve plant production and fruit quality, without resulting in environmental and food contaminations. Here, the effects of the application of Expando, a biostimulant based on seaweed and yeast extracts, on plant productivity, fruit ripening times, and fruit quality of Solanum lycopersicum var. Micro-Tom were evaluated. After biostimulant treatment, a two-week reduction of ripening times and a concomitant enhancement of the production percentage during the earliest ripening times, in terms of both fruit yield (+110%) and size (+85%), were observed. Concerning fruit quality, proximate analysis showed that tomatoes treated…
Quorum Sensing and Density-Dependent Dispersal in an Aquatic Model System
2012
International audience; Many organisms use cues to decide whether to disperse or not, especially those related to the composition of their environment. Dispersal hence sometimes depends on population density, which can be important for the dynamics and evolution of subdivided populations. But very little is known about the factors that organisms use to inform their dispersal decision. We investigated the cues underlying density-dependent dispersal in interconnected microcosms of the freshwater protozoan Paramecium caudatum. In two experiments, we manipulated (i) the number of cells per microcosm and (ii) the origin of their culture medium (supernatant from high-or low-density populations). …