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1.
Males of the sugarcane borer,Migdolus fryanus (Coleoptera: Cerambycidae), are attracted to females by means of a sex pheromone. Mating usually occurs during a few days from October to March under field conditions in São Paulo State, Brazil. This work reports on mating of this species as affected by daily climatic factors, during a single nuptial flight. Maximum male capture by the natural sex pheromone occurred from 1000 to 1100 AM at air and soil temperatures of 30.0°C and relative humidity of 57.0%. As these temperatures increased, females burrowed into the soil, as they are more sensitive to heat than males. Thus, it was concluded that sex pheromone-mediated mating in this cerambycid is directly affected by temperatures of air and soil.  相似文献   

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Effects of rate and time of nitrogen fertilization on growth, yield and yield components of upland cotton (Gossypium hirsutum L) were studied in two years (1975–76). Four rates of nitrogen application (0, 26, 52 and 78 kg ha–1) timed at 3 or 8 weeks after sowing were compared. Seed cotton yield components increased significantly with increased N application at least up to 52 kg N ha–1, with yield increases between 49% and 73%. Seed cotton yield was influenced by treatments mainly through boll number. Both crop growth rate and fruiting were enhanced by nitrogen fertilization. Applying N at 8 weeks (flowering) favoured yield only slightly over that at 3 weeks (thinning), but improved crop growth and fruiting by about 64% and 24%, respectively. There were significant N rate × time interactions in favour of fertilization at flowering. Applying 52 kg N ha–1 at 8 weeks seems best for cotton in the Nigerian savannah.  相似文献   

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The response of two okra (Abelmoschus esculentus L. Moench) varieties (White velvet and NHAE 47-4) to fertilization in northern Nigeria was examined using four rates of nitrogen (0, 25, 50 and 100 kg ha–1) and three rates of phosphorus (0, 13 and 26 kg ha–1). Nitrogen application significantly increased green pod yield, pod diameter, number of fruits per plant, number of seeds per pod and pod weight. Application of phosphorus also significantly increased green pod yield, pod number and number of seeds per pod. The two varieties responded to nitrogen application differentially with respect to green pod yield. For optimum green pod yield of White velvet 35 kg N ha–1 is suggested while for variety NHAE 47-4, N fertilization can be increased to 70 kg ha–1. There was no differential response of varieties to phosphorus fertilization for green pod yield; however, the application of 13 kg ha–1 enhanced the performance of both varieties.  相似文献   

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Hesperetin 7-rutinoside (Hesperidin) and taxifolin 3-arabinoside were detected in the soils associated with the rapidly spreading perennial weed,Pluchea lanceolata. In the present investigations, inhibitory potential of the aqueous extracts of the two compounds was established and confirmed through growth experiments pertaining to seed germination and seedling growth of radish, mustard, and tomato, with 10–4 M solutions of the authentic samples. The significance of the water-soluble compounds present in the rhizosphere zones of the weed and its interference potential is commented upon.  相似文献   

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Leaf extracts ofBunias orientalis were shown to inhibit seed germination of a variety of cultivar plant species and of species cooccurring withB. orientalis in the field. Root exudate solutions and leaf litter leachates ofB. orientalis were tested for their allelopathic activity using seedling growth assays. Additionally, in comparative seedling growth assays soil cores removed from denseB. orientalis stands were tested bimonthly for elevated allelopathic effects. The impact of root exudates on seedling growth was generally weak and varied between species. Similar results were obtained for the effect ofB. orientalis leaf litter leachates on seedlings grown in sand culture relative to the effect of leaf litter leachates of a plant species mixture. When soil as a growth substrate was used, no consistent differences in seedling growth were obtained between the two litter leachate treatments. In the soil core experiment seedlings grown in soil cores collected from a denseB. orientalis stand unexpectedly showed better performance than seedlings grown in soil cores collected from a nearby mixed plant stand withoutB. orientalis, at least in early spring and late autumn. Predominating nutrient effects are, therefore, assumed to conceal a potentially increased allelopathic effect of soil beneath denseB. orientalis stands. It is concluded that other factors than allelopathy must be investigated to explain the rapid establishment of dense stands of this alien plant species.  相似文献   

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Some issues have been critically discussed regarding the cell-impedance-controlled model inspired by the recent publication entitled “Reply to remarks on Discussion of three models used for the investigation of insertion/extraction processes by the potential step chronoamperometry technique [C. Montella, Electrochim. Acta 50 (2005) 3746] by H.-C. Shin, S.-I. Pyun, K.-N. Jung” [Electrochim. Acta 51 (2006) 2775]. In particular, two points on the definition of the internal cell resistance and the intersection phenomenon of chronoamperometric curves (CAs) have been revisited on the basis of the combination of experimental and theoretical approaches.  相似文献   

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Directed evolution has paved the way to a new era of protein and nucleic acid molecules with improved and enhanced properties. The utmost important component of directed evolution is random mutations in a defined DNA sequence. The utility of random chemical mutagenesis in directed evolution studies is dwindling due to the inherent flaws with whole-organism mutagenesis and the in vitro approach. Here, we report a novel Dual Approach to Random Chemical Mutagenesis (DuARCheM) to introduce random mutations in a defined DNA fragment. DuARCheM involves in vivo chemical mutagenesis and in vitro genetic manipulations. The resulting library revealed an accumulation of mutations in its members. These results imply that the parent mutation is carried in the further generations within the same library. This method might help to change random chemical mutagenesis because the combination of in vivo and in vitro approaches mimics the amplification and mutation that is performed by PCR-based mutagenesis, and at the same time the mutations are confined to the desired gene. Moreover, the mutagen pressure is greater in chemical mutagenesis than in a Taq-polymerase-based error-prone system. Concomitant amplification and mutation in the DuARCheM method leads to a better spectrum of mutants because the plasmid construct is exponentially amplified in the presence of mutagen pressure, unlike in the in vitro chemical mutagenesis system in which the template molecule does not replicate. This work is able to nullify all the disadvantages that are associated with random chemical mutagenesis, and could make random chemical mutagenesis an indispensable tool in directed evolution studies.  相似文献   

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周翠凤  李红  李伟善 《精细化工》2003,20(8):486-488,505
应用循环伏安法和微分脉冲伏安法研究了K3[Fe(CN)6]溶液中普鲁士蓝(PB)修饰电极的制备及其电化学行为。结果表明,在连续循环伏安扫描的条件下,K3[Fe(CN)6]会在对电极上发生解离生成Fe3+,Fe3+可以跟单室电解池三电极体系中的[Fe(CN)6]3-生成在Au电极表面有较强吸附作用的PB,所获得的PB修饰电极的稳定性受介质和外加电位的影响。修饰电极上的PB在c(KCl)=0 2mol/L中性或弱酸性溶液中于-0 10 5V较稳定,而在c(H2SO4)=1 0mol/L溶液中PB会在Au电极上溶出;于-0 11 5V扫描时PB也会在Au电极上溶出。尤为重要的是,所获得的PB修饰电极对H2O2的还原既有很好的间接电催化作用,又可以降低H2O2在其上反应的活化能,对H2O2还原反应的电子传递起到促进作用。  相似文献   

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Two different field experiments were conducted for two years during 1985–86 and 1986–87 to study the relationship of Mn (0, 15 and 30 kg ha–1) with Fe (0, 15 and 30 kg ha–1) and Zn (0, 10 and 20 kg ha–1) under two fertility (NPK) conditions on yield and quality of opium poppy. The main effect of these micronutrients with respect to latex yield was highest at 15 kg ha–1 of Mn or Fe and 10 kg ha–1 Zn. Increasing the level beyond that resulted in reduction in latex yield. Highest response was observed when 15 kg ha–1 Mn was applied with either 15 kg ha–1 Fe or 10 kg ha–1 Zn. Morphine, codeine, narcotine and thebaine content of the latex was highest with 15 kg Mn, 15 kg Fe or 10 kg ha–1 Zn or the combined application of 15 kg Mn with 15 kg Fe or 10 kg Zn ha–1.CIMAP Publication No. 961  相似文献   

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Sun Y  Gou S  Liu F  Yin R  Fang L 《ChemMedChem》2012,7(4):642-649
A series of platinum(II) complexes with N-monocyclopentyl/cyclohexyl derivatives of 1R,2R-diaminocyclohexane as carrier ligands and dicarboxylate anions as leaving groups were synthesized and characterized. All complexes were characterized by elemental analysis, IR, (1)H NMR, and (13)C NMR spectroscopy, as well as ESIMS. The in vitro antiproliferative activities were tested by MTT assay against four human cancer cell lines; breast carcinoma (MCF-7) and colon cancer (HCT-116) cells were particularly sensitive, especially to complexes 1f (IC(50) =9.81 and 1.49 μM) and 2f (IC(50) =4.59 and 0.36 μM). Flow cytometry indicated that representative compounds exert cytotoxicity toward MCF-7 and HCT-116 cells through induction of apoptosis and blockage of cell-cycle progression in the S phase, similar to cisplatin. The interaction between the platinum(II) complexes and pET22b plasmid DNA was observed by agarose gel electrophoresis, revealing that complex 2f has the capacity to distort plasmid DNA in a manner distinct from that of oxaliplatin.  相似文献   

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The CO2 reforming of methane over reduced NiO/MgO solid solution catalysts was studied at 800°C by a novel transient method, which couples a broadened pulse of CH4/CO2 with a step change to the carrier gas and/or with a sharp isotopic pulse of either 18O4, CO18 2 or 13CO16 2. The response curves indicated that two kinds of oxygen were formed over the catalysts during reaction: adsorbed oxygen which reacts fast with C species and lattice oxygen which reacts more slowly with C species. One concludes that a redox cycle of lattice oxygen formation through the oxidation of Ni and its reaction with C species takes place on the catalyst surface. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

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