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排序方式: 共有696条查询结果,搜索用时 31 毫秒
31.
Sodium bicarbonate reduces postharvest decay development on melons   总被引:1,自引:0,他引:1  
Sodium bicarbonate (SBC) inhibited in vitro mycelial growth of A. alternata, Fusarium spp. and R. stolonifer. SBC action was fungistatic rather than fungicidal. Coating commercially harvested ‘Galia’ and ‘Ein-Dor’ melons with wax containing 2% SBC reduced decay incidence after storage and shelf life simulation by four to seven-fold, to a commercially acceptable level of 6–7%, compared to untreated or waxed-treated controls. This treatment also maintained the fresh and blemish-free appearance of the fruit at harvest. Higher concentrations of SBC (3%) were phytotoxic and significantly reduced general fruit appearance. A trial shipment by sea transport to Europe demonstrated that 2% SBC incorporated into a wax coating maintained the marketability of ‘Galia’ melon fruits compared to that of untreated fruit. SBC can be an alternative biocide to the fungicide imazalil, thus eliminating unwanted residues on melon fruits.  相似文献   
32.
B. Schulz    R. Kreps    D. Klein    R. K. Gumber  A. E. Melchingeru 《Plant Breeding》1997,116(5):415-422
The univoltine European corn borer (ECB) has become a major limiting factor for maize (Zea mays L.) production in central Europe. The objective of this study was to survey the genetic variation for ECB resistance in European elite maize germplasm. Eighteen flint and 23 dent inbreds were screened under artificial ECB infestation at two locations in 1993 and 1994. Resistance was assessed by damage rating of broken plants, measurement of tunnel length in dissected stalks, and yield reduction in infested plots relative to insecticide-protected control plots. Flint lines showed significantly greater means for damage rating than dent lines with grain yield reduction of 35% and 24%, respectively. Significant genotypic variances among lines and high heritabilities were found for agronomic traits and damage rating. Heritabilities were intermediate for tunnel length and relative grain yield. Significant associations of days to silking, ear dry matter content, and dry matter yield of the whole plant with damage rating and tunnel length suggested a better resistance in late-maturing, high-yielding inbreds. Genotypic correlations of relative grain yield with tunnel length and damage rating ranged between ?0.46 and ?0.72. Partial correlations, eliminating the effect of flowering time, confirmed these associations. Damage rating of stalks is the most suitable trait for evaluation of ECB damage owing to its high heritability and easy recording. Tunnel length below the primary ear is a useful trait for assessing antibiosis because it is not correlated with days to silking. Inbreds with extreme resistance and susceptibility were identified which can be used as parents for establishing breeding and QTL mapping populations.  相似文献   
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34.
Antioxidant capacity of hydrophilic and lipophilic extracts from eight broccoli genotypes was compared using the oxygen radical absorbance capacity (ORAC) assay. Each genotype was analyzed for carotenoid, tocopherol, ascorbic acid, and flavonoid content. Results indicate that the antioxidant capacity of hydrophilic extracts ranged from 65.8 to 121.6 micromol trolox equivalents (TE)/g of tissue, and the capacity of lipophilic extracts ranged from 3.9 to 17.5 micromol TE/g. Ascorbic acid and flavonoid content of the hydrophilic extracts did not explain the total variation in antioxidant capacity of those extracts, suggesting either the presence of other antioxidant components that have yet to be identified or that the known antioxidants are producing synergistic effects. The carotenoids did correlate with antioxidant capacity of the lipophilic extracts and accounted for the majority of the variability in that fraction. The variability in hydrophilic and lipophilic antioxidant capacity found among these genotypes suggests that potential efficacy from antioxidants will vary considerably from genotype to genotype.  相似文献   
35.
A liquid chromatographic method for the determination of flucytosine in capsules was collaboratively studied by 7 laboratories. The method uses a C18 reverse phase column, water-methanol-acetic acid mobile phase containing 1-octanesulfonic acid sodium salt, p-aminobenzoic acid as internal standard, and photometric detection at 285 nm. The mean recovery value (+/- SD) of flucytosine from a synthetic formulation representing capsules was 99.2 +/- 1.72% (CV = 1.73%). Composited samples of 250 and 500 mg commercial capsules gave assay values of (mean +/- SD) 103.17 +/- 2.21 and 99.29 +/- 1.29% of declared, respectively. CV values were 2.15 and 1.30%. Reproducibility and repeatability CVs were 2.19 and 1.50%, respectively, for the 250 mg capsules, and 1.34 and 0.63%, respectively, for the 500 mg capsules. The method has been adopted official first action.  相似文献   
36.
Quantitative structure activity relationships (QSAR) and comparative molecular field analysis (CoMFA) are applied in order to explain the aroma of 46 bell-pepper aroma compounds. Biological activities log(1/c) values are used, where c stands for the detection threshold value of the aroma compound in water. Results of conventional QSAR and CoMFA are both satisfactory in statistical significance and predictive ability. We construct a qualitative model using the graphic features of CoMFA together with the results of "classical" QSAR analysis, which is performed by multiple linear regression. Finally, the human olfactory detection threshold values of excluded pyrazines are successfully predicted. This makes CoMFA and QSAR two important tools for designing new aroma compounds and in elucidating the mechanism of odor-receptor interaction.  相似文献   
37.
Fatty acids obtained from seed oils of crambe (Crambe abyssinica) and camelina (Camelina sativa) via alkaline saponification or steam splitting were esterified using lipases as biocatalysts with oleyl alcohol and the alcohols derived from crambe and camelina oils via hydrogenolysis of their methyl esters. Long-chain wax esters were thus obtained in high yields when Novozym 435 (immobilized lipase B from Candida antarctica) and papaya (Carica papaya) latex lipase were used as biocatalysts and vacuum was applied to remove the water formed. The highest conversions to wax esters were obtained with Novozym 435 (> or =95%) after 4-6 h of reaction, whereas with papaya latex lipase such a high degree of conversion was attained after 24 h. Products obtained from stoichiometric amounts of substrates were almost exclusively (>95%) composed of wax esters having compositions approaching that of jojoba (Simmondsia chinensis) oil, especially when crambe fatty acids in combination with camelina alcohols or camelina fatty acids in combination with crambe alcohols were used as substrates.  相似文献   
38.
Three different types of biological experiments on samples of martian surface material ("soil") were conducted inside the Viking lander. In the carbon assimilation or pyrolytic release experiment, (14)CO(2) and (14)CO were exposed to soil in the presence of light. A small amount of gas was found to be converted into organic material. Heat treatment of a duplicate sample prevented such conversion. In the gas exchange experiment, soil was first humidified (exposed to water vapor) for 6 sols and then wet with a complex aqueous solution of metabolites. The gas above the soil was monitored by gas chromatography. A substantial amount of O(2) was detected in the first chromatogram taken 2.8 hours after humidification. Subsequent analyses revealed that significant increases in CO(2) and only small changes in N(2) had also occurred. In the labeled release experiment, soil was moistened with a solution containing several (14)C-labeled organic compounds. A substantial evolution of radioactive gas was registered but did not occur with a duplicate heat-treated sample. Alternative chemical and biological interpretations are possible for these preliminary data. The experiments are still in process, and these results so far do not allow a decision regarding the existence of life on the plonet Mars.  相似文献   
39.
Genetic and immunological complexity of major histocompatibility regions   总被引:24,自引:0,他引:24  
There are genetic differences within the major histocompatibility complex of the mouse which lead to skin graft rejection but which cannot be detected serologically. When confronted with these differences on allogeneic cells, lymphocytes proliferate in vitro. In other cases, in vitro lymphocyte proliferation but no skin graft rejection is associated with loci that are linked to but genetically separable from the loci controlling the serologically defined antigens.  相似文献   
40.
Griseofulvin: a teratogenic study   总被引:4,自引:0,他引:4  
Griseofulvin, a fungistatic agent, was administered in oral doses of 125 to 1500 milligrams per kilogramn per day to pregnant rats during organogenesis. Evaluation of the offspring from dams treated with the largest doses, 63 and 75 times a therapeutic dose in man, indicated decreased survival rates and a syndrome of malformations.  相似文献   
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