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The dynamic recent development of technologies provides more and more new tools, thanks to which it is possible to quickly detect and identify the chemical composition of volatile organic compounds of fungal origin. An ‘electronic nose’ (e−nose) is one of such tools. The Forest Research Institute launched in the period of 2018−2020 the project entitled ‘Forecasting threats to forest ecosystems through the implementation of innovative electronic odor recognition system’. Its aim is to use an electronic nose to detect the odors of fungal pathogens that cause damping−off of seedlings belonging to Fusarium, Rhizoctonia, Cylindrocarpon, Phytophthora and Pythium genera as well as pine foils on an example of pine tree lappet caterpillars (Dendrolimus pini L.). In presented paper special attention was paid to the organic compounds of fungal origin. Many authors indicate that a large number of fungi secrete specific organic compounds that can be used to recognize them. The composition of these compounds may, however, differ depending on the conditions in which the organism develops or even on the virulence itself. Similar research made it possible to introduce an e−nose device for general use. They are used, inter alia, at airports to detect dangerous substances, to determine the quality of coffee, or to check food for its suitability for consumption. The aim of this work is to review the basic information on the volatile organic compounds released by fungi, their composition and the possibility of using an electronic nose for their early detection. Paper provides information on: methods used to identify volatile organic compounds, the basic differences between the discussed methods and information on the examples of the use of this technology in various industries, from the food industry, through medicine, to the army.
Ochrona upraw przed grzybami patogenicznymi dla roślin jest jednym z podstawowych elementów zapewniających wysokie plony. Niestety, odporność na fungicydy jest zjawiskiem coraz częściej występującym u patogenów. Przyczyną zaniku ochronnego działania stosowanych substancji czynnych są najczęściej mutacje w genach białek targetowych dla fungicydów. Do innych czynników powodujących wzrost odporności grzybów na fungicydy zalicza się m.in. zwiększenie ekspresji w/w białek, syntezę alternatywnych enzymów zastępujących funkcje blokowanych enzymów lub usuwanie z komórek fungicydów przez transportery ABC i MFS. Obecnie, ze względu na wzrost częstości tego zjawiska coraz większe znaczenie odgrywa stosowanie fungicydów zgodnie z praktykami zapobiegającymi powstawaniu odporności u grzybów.
Insecticides most often inhibit the development of fungal diseases, but can also stimulate them. The mechanisms of these phenomena are discussed and examples are given. The protective effect may be the result of direct pesticide influence on the pathogen, host susceptibility or other biocenotical components. The important factor is pest control which limits the infection of plants through the wounds caused by insects. Knowledge of side effect of insecticides on plant diseases may have important role during the application of pesticide mixtures and enable its usage in integrated plant disease control.
Scots pine is the most common tree species in Poland with the share in the species structure of Polish forests exceeding 58%. The most dangerous pathogen of this species is Phellinus pini (Brot.) Pilát), which causes the white pocket rot (also called red ring rot) of pine heartwood. It is estimated that as a result of the fungus’s activity, about 8% of annually harvested pine stems is damaged and worthless. As the Ph. pini damages only heartwood, it is often recognized that its occurrence has no influence on the tree’s physiology. As it is still unknown whether the presence of this fungus also does not affect the cambium responsible for the radial growth. We carried out studies in Scots pine stands located in the Radziwiłłów Forest District (central Poland). We investigated trees from 5th and 7th age classes (Biała Góra and Budy Stare forests, respectively). A total of 60 trees were sampled (30 per site). Half of them were specimens showing advanced symptoms of sickness, while the others were healthy specimens with no evidence of infection. From each tree we took one increment core and measured the tree−ring widths. Average tree−ring width was in case of healthy trees significantly higher than for sick trees. The research showed a significant, even of a dozen percent, reduction in the annual increment of infected trees in relation to healthy trees growing on the same site. Presumably, unidentified chemicals secreted to the cambium by the growing mycelium of Ph. pini may be responsible for this. It also seems that this relationship is progressing with the growing age of tree stands and is particularly visible in old stands, for example in reserves. Thus, Ph. pini could be one of the factors limiting the natural age of pine trees and accelerating their dieback. We also found that the growth of trees affected by the disease is influenced by a factor other than climatic, disturbing the natural rhythm of their radial increments. This factor is most likely the presence of mycelium of Ph. pini in the wood.
In laboratory plate studies on the effect of L-histidine on the fungistatic action of 2,4,6- trihydroxybenzencarboditioic acid (TBKD) was recorded. A gradual increase of concentration of L-histidine in the mineral medium at first weakens and then increases inhibitory properties of the system. The mechanism of the molecular co-operation of the amino acid was also discussed.
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