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21.
Carbendazim-resistant (RS) and control (CS) strains ofFusarium sporotrichioides Sherb., previously developed in our laboratory, were exposed to graded concentrations of azoxystrob in in broth media under
shake-culture conditions for 2, 3, 4 and 8 days. Azoxystrobin concentrations were 0, 1, 10 and 100 mg 1-1 broth and cultures were incubated at a constant 25°C. Mycelial growth was significantly affected by strain (P<0.01), azoxystrobin
concentration (P<0.001) and incubation time (P<0.001). Combined results for the four incubation times showed that CS yielded
higher mycelial mass than RS (P<0.01) only in the absence of azoxystrobin. At fungicide additions of 1, 10 and 100 mg P-1 mycelial growth was reduced (P<0.001) with minimal strain differences (P>0.05) at all three doses of azoxystrobin. Significant
(P<0.05 or better) strain-fungicide interactions were recorded in trichothecene production following exposure to azoxystrobin.
At 4 and 8 days of incubation, the 10 mg 1-1 addition of azoxystrobin stimulated T-2 toxin synthesis (P<0.05) only in RS cultures. In contrast, T-2 toxin enhancement
in CS cultures occurred only on day 8 but at a lower level of azoxystrobin (1 mg1-1). Thus, the stimulation of T-2 toxin synthesis depended upon strain and azoxystrobin level. Production of diocetoxyscirpenol
(DAS) was affected by a more complex set of interactions. Overall means showed that, in comparison with initial values (on
day 2 or 3), DAS output maximized significantly(P<0.05) on day 4 in RS cultures and on day 8 in CS. Marked strain effects were observed on exposure to the 10 mg 1-1 level of azoxystrobin. At this level, DAS production was enhanced in RS only after 4 (P<0.01 ) and 8 (P<0.05) days of incubation,
while in contrast, CS reduced DAS production. As with T-2 toxin, DAS production in CS was stimulated (P<0.05 or better) only
at low exposure levels of azoxystrobin. In the case of neosolaniol (NEO), however, the main effect of strain was significant
(P<0.05), with CS producing consistently more of the mycotoxin than RS on day 4 of the experiment. At this point, the NEO:T-2
toxin ratio was also higher in CS (0.63) than in RS (0.12), a feature reported by us previously. In conclusion, the present
investigation has shown for the first time that the development of resistance to one fungicide can affect trichothecene production
inF. sporotrichioides on exposure to a second fungicide. These results have been incorporated into a new classification scheme for fungicide efficacy
which is also presented in this paper.
http://www.phytoparasitica.org posting Oct. 7,2001. 相似文献
22.
Kenichi?TsuchiyaEmail author Christophe C.M.?D’Ursel Mitsuo?Horita Yuzo?Nozu 《Journal of General Plant Pathology》2003,69(5):310-315
Strains of Xanthomonas campestris pv. vesicatoria Dye 1978 (Xcv), the causal agent of bacterial spot, have been classified into two groups based on their ability to hydrolyze starch. Three monoclonal antibodies (MAbs), 7AH10, 5HB3, and 4AD2, were produced immunized against the living bacteria and were specific to and could distinguish Xcv strains able or unable to hydrolyze starch (Amy+ or Amy–). The MAb 7AH10, obtained against strain UPB141(Amy–) reacted in an enzyme-linked immunosorbent assay with all the Amy– strains (n = 19) and 1 of 11 Amy+ strains. Against Xcv 2625, an Amy– unusual phenotype strain, MAb 5HB3, recognized 97% of our worldwide collection of Xcvs (n = 30). Also against that strain, the MAb 4AD2 reacted with none of the homologous Amy– phenotypes and with 90% (n = 11) of the heterologous Amy+ phenotypes. For all the MAbs, cross reactions with other pathovars or species were less than 4% (n = 67). By assaying a Japanese collection of strains against the three MAbs, the Amy+ strains were distinguished from the Amy– strains, and their relation with other world strains could be demonstrated. All the MAbs reacted with the lipopolysaccharide fraction of the bacterial cell wall during immunoblotting. 相似文献
23.
Floriane L’Haridon Sébastien Aimé Claude Alabouvette Chantal Olivain 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):239-246
The aim of this study was to assess the biocontrol capacity of rev157, a non-pathogenic mutant of a pathogenic strain of Fusarium oxysporum f. sp. melonis (Fom24). Inoculated in association with the virulent parental strain, the mutant rev157 did not protect the host plant (muskmelon)
against infection by Fom24. Applied on flax, a non-host plant, the mutant rev157 was not able to protect it against its specific
pathogen F. oxysporum f. sp. lini. On the contrary the parental strain Fom24 did protect flax as well as a soil-borne biocontrol strain (Fo47). Since the mutant
rev157 was affected neither in its growth in vitro nor in its capacity to penetrate into the roots, it can be speculated that
the mutation has affected traits responsible for interactions within the plant. In F. oxysporum the pair of strains Fom24/rev157 is a good candidate to identify genes involved in the biocontrol capacity of F. oxysporum and to test the hypothesis of a link between capacity to induce the disease and capacity to induce resistance in the plant. 相似文献
24.
Robert A. Spotts Kelly M. Wallis Maryna Serdani Daniel T. O’Gorman Peter L. Sholberg 《Postharvest Biology and Technology》2009,51(2):227-231
The objectives of this study were to develop primers and a real time PCR protocol for the postharvest biocontrol yeast Cystofilobasidium infirmominiatum (Cim). The application of this technology was developed to quantify Cim on the surfaces of apple, two pear cultivars, and sweet cherry fruit treated over a range of concentrations. Statistically significant relationships were observed between Cim DNA on fruit surfaces, expressed as μg/m2, and CFU/L of dip suspensions for apple, pear, and sweet cherry. In addition, the relationship for each fruit was significantly different from the other three fruits. Threshold values of concentrations of Cim DNA on the fruit surface were calculated based on regression equations and a dose of 2.0 × 1011 CFU/L of dip suspension, the dose for optimum decay control, and were 4.8, 7.0, 16.5, and 25.2 μg/m2 for Bosc pear, Lapins sweet cherry, d’Anjou pear, and Golden Delicious apple, respectively. Monitoring Cim DNA concentration on fruit surfaces will assure that Cim is being properly applied to fruit and that a sufficient number of cells are present for optimum decay control. 相似文献
25.
M. Nang’alelwa 《EPPO Bulletin》2008,38(3):464-469
Invasive Alien Species (IAS) are a major threat to biodiversity and national economies worldwide. Public awareness and support is critical for the success of any interventions aimed at controlling and managing such invasions. Various communication tools have been identified for the implementation of public awareness programs. Assessment of public perceptions, attitudes and knowledge levels should be an integral part of any public awareness activities. This paper reports the communication actions undertaken in the Victoria Falls World Heritage Site by the Removing Barriers to Invasive Plant Management in Africa (RBIPMA) project during the year 2007. Several awareness meetings with various stakeholders were conducted during the year. A number of posters, leaflets, brochures and newsletters have been produced. Production of radio and television documentaries is currently ongoing. A pre‐knowledge survey was conducted to determine the baseline status as regards knowledge and awareness levels on IAS in the project area. A post‐knowledge survey will be conducted at a subsequent stage to assess the effectiveness of the project interventions on public awareness and knowledge levels. Recommendations for future action are also presented. 相似文献
26.
27.
Carlo Bonini Maurizio D’Auria Pasqua Di Maggio Rachele Ferri 《Industrial Crops and Products》2008,27(2):182-188
Steam explosion of corn stalk in the presence of 3% sulphuric acid at 200 °C for 5 min gave the highest recovery of lignin. Lignin has Mw = 2640 and Mz = 93,994. In the UV spectrum absorptions at λ = 231 and 280 nm were recorded. 1H NMR spectrum of lignin showed signals attributable to cinnamaldehyde units, guaiacyl units, and syringyl units. Syringyl and guaiacyl units are in 1:1 ratio. 13C NMR spectrum showed signals for guaiacyl, syringyl, and p-hydroxyphenyl units. The spectrum showed a prevalence of guaiacyl units. The 13C NMR spectrum is in agreement with the presence of cinnamic units. The same characterization was performed on lignin from pine. The irradiation of lignin from pine from steam explosion process in the presence of oxygen, in conditions described for the formation of superoxide ion, for different irradiation time was followed isolating the lignin and determining the average molecular weight. The experiments showed that, until 8 h irradiation, Mn decreases, while Mw and Mz increases. After 8 h irradiation an inverse behaviour was observed, with an increase of Mn and a decrease of Mw and Mz. These results are in agreement with an initial polymerization process followed by a photoinduced degradation. Ozonization was carried out in acetonitrile–methanol solution. The reaction showed a zero-order kinetics. After 50 min the average molecular weight of lignin is the half. The reaction mixture was analyzed by using GC–MS. Oxalic acid was determined. 相似文献
28.
Vieira Aline Bomfim Restrepo Mariana Alvarez Auzenne Danielle Molina Kevin O’Sullivan Meghan Machado Marcus Vinicius Cavanaugh Sarah Marie 《Veterinary research communications》2022,46(2):527-535
Veterinary Research Communications - Obesity is considered the most common nutritional disease of dogs. Even though overt obesity is more likely to impair health, even moderately overweight dogs... 相似文献
29.
To determine the effect of shade on morphology, growth and biomass allocation in Picea sitchensis, Larix × eurolepis and Thuja plicata, seedlings were grown in the open or under shadehouses providing 25%, 50% and 75% reductions of full-light for two growing
seasons. For most of the characteristics assessed there was no significant interaction between species and shade indicating
that the morphological responses to changing shade treatments were not species-dependent. After two growing seasons the mean
height increment for the three species was significantly greater in 25% (76.1 cm) and 50% shade (74.9 cm) than in the open
(69.5 cm). Root collar diameter increment, shoot, root and total biomass declined significantly with increasing shade while
the opposite was true for the height:diameter ratio. In both western red cedar and hybrid larch the shoot:root ratio was significantly
greater in the shade while in Sitka spruce this characteristic was not influenced by shade. While all species had significantly
greater specific shoot areas in 75% shade than in 0% shade, this trend was particularly pronounced in hybrid larch. In hybrid
larch and western red cedar, the normalised specific projected shoot area increased significantly with increasing shade. The
opposite trend was observed for Sitka spruce. We conclude that in the main the species studied demonstrated similar shade
acclimation responses despite their reported differences in shade tolerance. 相似文献
30.
Through studying seven analytic trees from two stands ofPinus koraiensis artificial forests, the results show that the individual variation coefficient of tree heigh, dbh and volume decreases with
age increasing after age of 25. Age of 25 is the age that difference of individual growth is from acute difference to comparatively
stability. The optimum selection age is 25a forPinus koraiensis’s artificial forests according to the analysis of juvenile-mature correlation, and early selection efficiency.
(Responsible Editor: Zhu Hong) 相似文献