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Antagonistic activity of 63 bacterial isolates, originating from soil and apple leaves, against Venturia inaequalis was studied in dual culture on PDA medium. Based on measurement of inhibition zones, 16 isolates appeared to be most active. Three of them /57M, 59M (Pseudomonas spp.) and 103M (Collimonas sp.), significantly protected apple trees against apple scab on Gala trees in the net-glasshouse. Of 6 ethanol plant extracts (sage leaf, rhizomes of Potentilla, oak and willow bark and the aboveground parts of St. John's-wort and tetterwort), the highest activity in inhibition of V. inaequalis conidia germination, even after 10- and 20-fold dilution in water, showed extract from rhizomes of Potentilla. Applied at two concentrations (5 and 10%) on Gala apple trees it totally protected leaves against apple scab.
The efficacy against fire blight of 3 antagonistic bacterial isolates (48M, 59M, 141M), strain C9-1 ̶ the active component of BlightBan (USA), the yeast based preparation Blossom Protect and copper preparations (Flow Brix 380 SC, Cuproflow 375 SC, Miedzian 50 WP) was evaluated on apple blossoms on Idared trees and Jonagold cut off branches. The highest efficacy was demonstrated after protective use of all bacterial isolates (82.7–92.0%) and Blossom Protect (83.5%). Miedzian 50 WP at the dose of 1.5 kg/ha appeared to be low effective. Two treatments with Blossom Protect applied during the blooming of apple trees cultivars Golden Delicious and Jonagold did not cause phytotoxicity on apples assessed after harvest. Because most fungicides used for protection of apple against fungal diseases are toxic to yeast in Blossom Protect, it seems that this preparation could be applicable against fire blight only in organic growing of apple.
We wrześniu 2009 roku, w komercyjnych uprawach szklarniowych falenopsis (Phalaenopsis lueddemanniana) w województwie łódzkim obserwowano nietypowe objawy chorobowe występujące na okołp 15% roślin. Na liściach 7. miesięcznych roślin występowały duże, brązowe, zapadnięte plamy otoczone żółtą, uwodnioną tkanką. Z pogranicza symptomatycznej tkanki pobierano próbki, z których wyizolowano na pożywkach King B i agar odżywczy bakterie, tworzące niewielkich rozmiarów płaskie kolonie koloru białego, o regularnych brzegach. Bakterie były gramujemne, wywoływały reakcję nadwrażliwości na tytoniu i nie posiadały właściwości pektynolitycznych w teście na ziemniaku. Analiza sekwencji fragmentu genu 16S rDNA, wybranych cech fenotypowych i testy patogeniczności na zdrowych roślinach Phalaenopsis pozwoliła na stwierdzenie, że czynnikiem sprawczym bakteryjnej brązowej plamistości jest Acidovorax cattleyae.
In the framework of the performed studies, the antibacterial activity of the following fungicides was evaluated: Miedzian 50 WG (active substance - a.s. 50% copper oxychloride), Ridomil MZ Gold 68 WG (a.s. 3.8% metalaxyl-M and 64%, mancozeb), Euparen Multi 50 WG (a.s. 50% tolylfluanid), Captan 80 WG [a.s. 80% N-(captan)], Dithane Neotec 75 WG (a.s. 75% mancozeb). The evaluation also concerned the essential oils: lavender, sage, lemon balm, clove, and a preparation based on thyme oil (BioZell). Each preparation and compound was tested against the following bacterial pathogens: Erwinia amylovora, Xanthomonas arboricola pv. corylina, X. arboricola pv. juglandis, Pseudomonas syringae pv. syringae, Agrobacterium tumefaciens (presently Rhizobium radiobacter). Each preparation and compound was tested at a concentration of 1,000 ppm of active substance. Copper oxychloride was also tested at a concentration of 1,500 ppm. Among the tested fungicides, metalaxyl-M with mancozeb, mancozeb alone, and copper oxychloride inhibited all of the tested strains of pathogenic bacteria. Tolylfluanid did not inhibit any of the bacteria used. Out of the investigated essential oils, the strongest inhibitors of bacteria were: sage, cloves, and BioZell. The protective activity of the above mentioned fungicides was also evaluated in vivo. They were assessed against fire blight on apple blossoms and pear fruitlets, against bacterial canker on sweet cherry fruitlets, and against crown gall on sunflower seedlings (the test plant). All fungicides were applied at the same concentrations as those in the in vitro tests. Only copper oxychloride was found to show protective activity against the studied diseases. This result indicates that the antibacterial properties of the other fungicides did not correspond with their activity on the plant organs used in the in vivo experiment.
Z kłączy cantedeskii odmian ‘Mango’, ‘Treasure’, ‘Black Magic’ z objawami miękkiej zgnilizny, wyizolowano bakterie tworzące szaro-białe kolonie na pożywkach King B i agar odżywczy z sacharozą. Fenotypowa charakterystyka tych bakterii umożliwiła ich zaklasyfikowanie do rodzaju Bacillus. Ponadto analiza sekwencji fragmentu genu kodującego 16S rRNA badanych bakterii wykazała, że należą one do gatunku Paenibacillus polymyxa. Badane izolaty wykazały aktywność pektynolityczną w testach na pożywce CVP i plastrach bulw ziemniaka. Ocena patogeniczności wykonana na odciętych ogonkach liściowych cantedeskii wykazała, że powodują one gwałtowną zgniliznę tkanek już po 24 godzinach od inokulacji. Z pogranicza zdrowej i chorej tkanki reizolowano bakterie o takich samych cechach fenotypowych, jak bakterie użyte do inokulacji. Jest to pierwsze doniesienie o Paenibacillus polymyxa jako sprawcy miękkiej zgnilizny na kłączach cantedeskii.
Effects of post−harvest wood−debris utilization and pre−planting soil preparation in clear−cut forest on the community structure of soil fungi and bacteria and their possible biological activity towards Armillaria and Heterobasidion were studied in 1− and 10−year−old Scots pine plantations in Bierzwnik and Międzychód Forest Districts (W Poland). Post−harvest wood−debris utilization included: (i) removal from the surface, (ii) spread of the coarse or chipped wood−debris on the surface and (iii) mixing of the chipped wood debris with the soil. Pre−planting soil preparation included: (i) deep furrowing, (ii) shallow turning of the topsoil, (iii) ridging and (iv) no ground preparation. The soil−dilution method was used for detection of fungi and bacteria in soil. Morphotyping was used for identification of fungi. Phenotypic traits and biochemical properties were used for identification of bacteria. Molecular method, MID−66 or BIOLOG® systems were additionally applied for identification of the most common bacteria. Removal of post−harvest wood−debris from the surface of the clear−cut land and shallow turning of the topsoil or ridging before planting increased abundance of fungi in soil of 1−year−old Scots pine plantation. Deep furrowing resulted in increased abundance of fungi and no ground preparation in increased abundance of bacteria in soil of 10−year−old Scots pine plantation. Increased abundance of fungi and bacteria was associated with increased abundance of taxa considered as antagonistic to Armillaria and Heterobasidion. Removal of the post−harvest wood debris and moderate or no mechanical intervention into the soil habitat on the clear−cut site before planting of Scots pine seedlings seems to create the habitat, which may be beneficial for the growth of young trees.
In order to limit the contamination problem in plant tissue cultures experiments on selection of media suitable for detection and isolation of bacteria contaminating plant tissue explants, and preliminary characterization of isolates were made. In the first experiment aiming at detection of bacteria in plant explants four strains representing genera most often occurring at our survey of plant tissue cultures, and earlier isolated and identified (Bacillus, Methylobacterium, Pseudomonas and Xanthomonas) were streaked on five bacteriological media (NA, King B, K, R2A and 523) and on the medium used for plant culture initiation – 1 MS with milk albumin (IM). All strains grew on all media but on K and IM at the slowest rate and on 523 medium at the fastest. The IM medium proved to be useful for immediate bacteria detection at the initial stage of culture. In the second experiment, aiming at characterization of isolates on the basis of colony growth and morphology 14 strains (Agrobacterium, Bacillus, Curtobacterium, Flavobacterium, Lactobacillus, Methylobacterium – 2 strains Mycobacterium, Paenibacillus, Plantibacterium, Pseudomonas, Stenotrophomonas, Xanthomonas, and species Serratia marcescens) were streaked on five microbiological media: KB, NBY, YDC, YNA and YPGA. All strains grew on all those media but at different rates. The only exception was the strain of Lactobacillus spp., which did not grow on King B medium. This medium allowed the detection of such characteristic traits as fluorescence (Pseudomonas) and secretion of inclusions (Stenotrophomonas). The third experiment was focussed on assessment of the sensitivity of detection of specific bacteria in pure cultures and in plant tissue cultures using standard PCR and BIO-PCR techniques with genus specific primers and 2 methods of DNA isolation. Results showed that the use of Genomic Mini kit enabled an increase of the sensitivity by 100 times as compared to extraction of DNA by boiling. Moreover, the application of BIO-PCR increased sensitivity of detection from 102 to 105 times over the standard PCR. If looking for unknown cultivable bacteria more effective detection seems to be use of microbiological method enabling detection on bacteriological media single cells in the fragments of explants or in wash liquids, in which fragmented explants were shaken.
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