Search results for "herb"
showing 10 items of 856 documents
Adsorption of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) by goethite.
2014
Interaction between the goethite surface and 4-chloro-2-methylphenoxyacetic acid (MCPA) herbicide was studied using density functional theory (DFT) calculations combined with molecular dynamics (MD). The important step made here lies in the use of a periodic DFT method enabling the study of a mineral surface of different protonation states, in strong contrast with previous molecular modeling studies limited to single protonation state corresponding to the point of zero charge. Different surface OH groups and MCPA proton states were used to mimic the strong effects of pH on the outer- and inner-sphere surface complexes that are theoretically possible, together with their binding energies, an…
Microtubule distribution in gravitropic protonemata of the mossCeratodon
1990
Tip cells of dark-grown protonemata of the moss Ceratodon purpureus are negatively gravitropic (grow upward). They possess a unique longitudinal zonation: (1) a tip group of amylochloroplasts in the apical dome, (2) a plastid-free zone, (3) a zone of significant plastid sedimentation, and (4) a zone of mostly non-sedimenting plastids. Immunofluorescence of vertical cells showed microtubules distributed throughout the cytoplasm in a mostly axial orientation extending through all zones. Optical sectioning revealed a close spatial association between microtubules and plastids. A majority (two thirds) of protonemata gravistimulated for > 20 min had a higher density of microtubules near the lowe…
La résistance du vulpin des champs aux anti-graminées dans les blés en France. La métabolisation : son importance crée une situation à risque
2006
National audience; La résistance du Vulpin aux anti-graminées inhibiteurs de l'acétyl-coenzyme carboxylase ACC],« fops » et « dimes ») constitue un problème de désherbage majeur en France. 243 populations de vulpin (116 essentiellement dans le nord-est de la France, 127en Côte-d'Or) ont été analysées à l'aide de tests biologiques de sensibilité à des inhibiteurs de l'ACC et de tests moléculaires d'identification de résistances de cible. Des résistances ont été identifiées dans 241 des 243 populations. L'essentiel (plus de 75%) des résistances aux deux « fops» les plus utilisés est dû à des résistances par métabolisation.Ces résistances sont les plus préoccupantes en terme de gestion chimiqu…
Highly Fluorinated 2,2′-Biphenols and Related Compounds: Relationship between Substitution Pattern and Herbicidal Activity
2013
A broad range of halogenated 2,2'-biphenols was tested for applicability as crop protection agents. The activity of these compounds toward four typical pest plants was observed after application by spraying of diluted solutions. Despite their rather simple structure, it was found that the studied compounds reveal a surprisingly high herbicidal impact. To gain a better understanding of the structure-activity relationship, specific sites of the molecule were chemically modified and the core structures thus gradually changed. The influence of the substitution pattern on the herbicidal properties is discussed, and conclusions on the active site of the biphenol structure are drawn. It was observ…
Herbalists, traditional healers and pharmacists: a view of the tuberculosis in Ghana
2014
This paper is the result of a visit by Brazilian researchers to Ghana, with the aim of improving understanding of the relationship between traditional healers and conventional health practices, specifically in relation to tuberculosis. Through this exploratory visit, this group of researchers promoted by the Edital Pro Africa (CNPq) had an opportunity to learn about, reflect on, and discuss the different social, economic and cultural realities and contexts that have led to the different health conditions and forms of healthcare in Ghana. Besides the direct relationship between the social and economic conditions of the country and the health of its population, it was also concluded that ther…
Glyphosate-based herbicide has soil-mediated effects on potato glycoalkaloids and oxidative status of a potato pest
2020
Glyphosate is the most used herbicide worldwide, targeting physiological pathways in plants. Recent studies have shown that glyphosate can also cause toxic effects in animals. We investigated the glyphosate-based herbicide (GBH)-induced changes in potato (Solanum tuberosum) plant chemistry and the effects of a GBH on the survival rate and oxidative status of the Colorado potato beetle (Leptinotarsa decemlineata). The beetles were reared on potato plants grown in pots containing soil treated with a GBH (Roundup Gold, 450 g/l) or untreated soil (water control). The 2nd instar larvae were introduced to the potato plants and then collected in 2 phases: as 4th instar larvae and as adults. The ma…
Application of Toxkit microbiotests for toxicity assessment in soil and compost
2004
The potential of Toxkit microbiotests to detect and analyze pollution in agricultural soil and the quality of compost was studied. The toxicity tests used included seed germination biotests using cress salad (Lepidum sativum L.), tomato (Lycopersicum esculentum L.), and cucumber (Cucumis sativus L.), and the Toxkit microbiotests included those with microalgae (Selenastrum capricornutum), protozoa (Tetrahymena thermophila), crustaceans (Daphnia magna, Thamnocephalus platyurus, and Heterocypris incongruens), and rotifers (Brachionus calyciflorus). Experiments on compost were undertaken in a modified solid-state fermentation system (SSF) and under field conditions (in a windrow). To promote th…
The effects of woodchip- and straw-derived biochars on the persistence of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA) in soils
2014
Sorption and degradation are the primary processes controlling the efficacy and runoff contamination risk of agrochemicals. This study assessed the influence of two biochars, made from woodchips and straw at a pyrolysis temperature of 725°C and applied to a loamy sand and a sandy soil in the concentration of 5.3 g 100 g(-1) sandy soil and 4.1 g 100 g(-1) loamy sand soil, or 53 t ha(-1) for both soil types, on degradation of the herbicide 4-chloro-2-methylphenoxyacetic acid (MCPA). Soils were spiked with 50 mg MCPA kg(-1) soil. In the sandy soil, significantly more MCPA remained after 100 days if amended with straw-derived biochar in comparison to wood-derived biochar. Both biochars types si…
Effects of Terbuthylazine on Soil Fauna and Decomposition Processes
1996
Abstract Acute lethal and sublethal effects of terbuthylazine and the commercial herbicide preparation Gardoprim [terbuthylazine is the active ingredient (a.i.)] on soil organisms (microbes, oppioid mites, two gamasid mite species, enchytraeids, and nematodes) were studied. In the humus soil terbuthylazine had no toxic effects on soil animals tested. However, the herbicide preparation had acute toxic effects on enchytraeids [no-observed-effect level (NOEL) 1.0 g a.i./m 2 ] and both gamasid mites (NOEL 2.4 and 5.0 g a.i./m 2 ). According to filter paper test, the LC 50 value for oppioid mites was 14.5 g a.i./m 2 . In the humus soil the commercial preparation caused no dose-related mortality …
Mediaatioita : fenomenologisen marxismin mahdollisuus
2013
Tutkimukseni tehtävänä on selvittää, onko fenomenologian ja marxismin synteesi mahdollista. Käsittelen 1930-luvun taitteen Herbert Marcusen fenomenologista marxismia esimerkkinä synteesin mahdollisuudesta. Näiden perinteiden yhdistäminen vaatii kuitenkin ensin syventymistä Marcusen ajattelun pohjana toimiviin hegeliläisen ja weberiläisen marxismin perinteisiin sekä Martin Heideggerin muotoilemaan fenomenologiaan. Marxismissa on perinteisesti painottunut yhteiskunnallisten rakenteiden ja fenomenologiassa yksilöllisen elävän kokemuksen näkökulma. Tällaisten eriävien lähtökohtien takia ne on usein asetettu jopa vastakohtaisiksi perinteiksi. Oleelliseksi kysymykseksi nouseekin sekä marxismin et…