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Fusarium moniliforme is a widespread facultative endophyte, primarily associated with corn, where it causes extensive crop damage.F. moniliforme can be toxigenic, the carcinogenic fumonisins being accumulated predominantly when the fungus colonizes corn plants. The
pathogen is transmitted both through contaminated seeds and through environmental inoculum. This study utilized markednit-mutantF. moniliforme inoculum in order to evaluate the quantitative significance of seedborne disease transmission. Greenhouse and field trials
demonstrated that seedborne isolates were responsible for up to 50% ofF. moniliforme disease. Seed treatment with the fungicide prochloraz was found to control seedborne transmission and to protect againstF. moniliforme seedling blight. The elimination of seedborne inoculum resulted in reduced incidence of kernel rot and avoided the increment
in soil inoculum accumulation associated with the introduction of infected seeds.
http://www.phytoparasitica.org posting July 10, 2003. 相似文献
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Hestrin S 《Science (New York, N.Y.)》2011,334(6054):315-316
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Yields of ‘Topaz’ mandarin, a self-incompatible local selection of ‘Ortanique’, were substantially increased by spraying with 20 p.p.m. gibberellin or by girdling at blossom time. The number of seeds increased with decreasing distance from ‘Minneola’ pollinizers, while fruit size and yields were not clearly affected. 相似文献
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Late wilt, a severe vascular disease of maize caused by the fungus Harpophora maydis, is characterized by relatively rapid wilting of maize plants before tasseling and until shortly before maturity. In Israel, the disease has become a major problem in recent years. The pathogen is currently controlled using cultivars of maize having reduced sensitivity. In an earlier work, we modified a molecular method for use as a diagnostic tool to evaluate disease progression in field-infested plants and showed that several fungicides suppressed H. maydis in vitro. Here, we examine the effect of different fungicides on disease progression in a contaminated maize field in the spring and summer of 2009 and 2010. The field was watered using a drip irrigation line for each row and the fungicides were injected directly into the drip line. One of the four fungicides tested, azoxystrobin, was highly effective compared with the control, inhibited the development of wilt symptoms and recovered cob yield by 100%. Although this is the first success in preventing disease symptoms in infested fields in Israel, the azoxystrobin treatment did not reduce the amounts of pathogen DNA in host tissues or delay its spread. Attempts to reduce concentrations of this fungicide or to apply it by spraying were less effective than the triple full dosage treatment. The presence of the pathogen in the host tissues of the successfully treated plants and its ability to undergo pathogenic variations are increasing the risk of pathogen resistance and the urgent need to develop new ways of controlling late wilt. 相似文献
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Rock hyraxes (Procavia capensis) were individually caged and were given two second-generation anticoagulants, difenacoum and difethialone, in fresh sliced apple bait. Mortality caused by 0.1-0.2 g kg?1 difenacoum bait was rather low: 0/6, 1/4 and 2/4 only. As a relatively high concentration in the bait was required, the use of difenacoum in the field is not possible because of environmental considerations. Mortality caused by 0.05 g kg?1 difethialone bait was 5/6, and by 0.065 g kg?1 6/6. The potential of using difethialone in the field is uncertain because of the prolonged treatment needed. 相似文献
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Sancak Y Peterson TR Shaul YD Lindquist RA Thoreen CC Bar-Peled L Sabatini DM 《Science (New York, N.Y.)》2008,320(5882):1496-1501
The multiprotein mTORC1 protein kinase complex is the central component of a pathway that promotes growth in response to insulin, energy levels, and amino acids and is deregulated in common cancers. We find that the Rag proteins--a family of four related small guanosine triphosphatases (GTPases)--interact with mTORC1 in an amino acid-sensitive manner and are necessary for the activation of the mTORC1 pathway by amino acids. A Rag mutant that is constitutively bound to guanosine triphosphate interacted strongly with mTORC1, and its expression within cells made the mTORC1 pathway resistant to amino acid deprivation. Conversely, expression of a guanosine diphosphate-bound Rag mutant prevented stimulation of mTORC1 by amino acids. The Rag proteins do not directly stimulate the kinase activity of mTORC1, but, like amino acids, promote the intracellular localization of mTOR to a compartment that also contains its activator Rheb. 相似文献
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Ultrasonic shear wave velocities of MgSiO3 perovskite at 8 GPa and 800 K and lower mantle composition 总被引：1，自引：0，他引：1
YD Sinelnikov G Chen DR Neuville MT Vaughan RC Liebermann 《Science (New York, N.Y.)》1998,281(5377):677-679
Ultrasonic interferometric measurements of the shear elastic properties of MgSiO3 perovskite were conducted on three polycrystalline specimens at conditions up to pressures of 8 gigapascals and temperatures of 800 kelvin. The acoustic measurements produced the pressure (P) and temperature (T) derivatives of the shear modulus (G), namely ( partial differentialG/ partial differentialP)T = 1.8 +/- 0.4 and ( partial differentialG/ partial differentialT)P = -2.9 +/- 0.3 x 10(-2) gigapascals per kelvin. Combining these derivatives with the derivatives that were measured for the bulk modulus and thermal expansion of MgSiO3 perovskite provided data that suggest lower mantle compositions between pyrolite and C1 carbonaceous chondrite and a lower mantle potential temperature of 1500 +/- 200 kelvin. 相似文献
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