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1.
《Journal of Cereal Science》2005,42(2):225-231
Wheat line L88-31 was transformed with a gene encoding an extended form of subunit 1Dx5 to study the relationship between subunit size and the effect on dough mixing properties. Four transgenic lines were recovered, one of which expressed a truncated form of the protein with mobility between those of the wild type and extended subunits. Comparison of the Mixograph profiles and gluten protein compositions with those of the control lines and a line expressing the wild type subunit 1Dx5 transgene showed that two of the transgenic lines had poor mixing properties and that this was associated with co-suppression of HMW subunit gene expression. The other two transgenic lines had improved mixing properties (measured as increased mixing time) and this was associated with increased proportions of large glutenin polymers. None of the transgenic lines expressing the extended form of the 1Dx5 subunit showed the ‘overstrong’ mixing properties exhibited by transgenic lines expressing the wild type 1Dx5 transgene. 相似文献
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The uptake of 2,4,5-T by spines of gorse (Ulex europaeus L.) was limited and not enhanced when picloram was added to the application solution. Translocation of 2,4,5-T in 6-month-old cuttings after treatment of a single spine or lateral branch was poor. The most significant accumulation of translocated herbicide occurred in stem tissue, with lesser amounts detected in root tissues, root nodules, stem apices and flowers. Untreated lateral branches or spines accumulated minimal amounts of herbicide. The pattern and extent of distribution of 2,4,5-T was not increased by addition of picloram. The lack of efficient control of gorse by 2,4,5-T can largely be attributed to its inadequate uptake and lack of true systemic translocation. 相似文献
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Charles P. Woloshuk Hugh D. Sisler Maria Chrysayi Tokousbalides Samson R. Dutky 《Pesticide biochemistry and physiology》1980,14(3):256-264
Tricyclazole (5-methyl-1,2,4-triazolo[3,4-b]benzothiazole) inhibits melanin synthesis in Pyricularia oryzae at concentrations less than 0.01 μg/ml. The primary site of inhibition in the biosynthetic pathway occurs between scytalone and vermelone. Accumulation of several metabolites derived from melanin precursors along branch pathways is associated with inhibition of melanin biosynthesis. At low tricyclazole concentrations (0.01–1 μg/ml), predominant accumulation of 2-hydroxyjuglone and 3,4-dihydro-3,4,8-trihydroxy-1-(2H)-naphthalenone (3,4,8-DTN) occurs as a result of the primary block between 1,3,8-trihydroxynaphthalene and vermelone. As the concentration of tricyclazole is increased from 1 to 10 μg/ml, flaviolin accumulation is markedly enhanced, whereas that of 3,4,8-DTN and 3,4-dihydro-4,8-dihydroxy-1-(2H)-naphthalenone is depressed, indicating possible secondary sites of inhibition in the main and branch pathways. Five melanin-deficient mutants of P. oryzae that phenotypically resemble the tricyclazole-treated wild-type strain were nonpathogenic or rarely infected two rice varieties. Three of the mutants studied were genetically defective in the melanin biosynthetic pathway at the site blocked by tricyclazole in the wild type. The wild-type strain converted both scytalone and vermelone to melanin; whereas the three mutants and the tricyclazole-treated wild type converted only vermelone to melanin. The data suggest a relationship between melanin biosynthesis and pathogenicity in P. oryzae. 相似文献
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用紫外荧光法测定鞭角华扁叶蜂末龄幼虫及滞育预蛹血淋巴中多胺的动态.结果表明:鞭角华扁叶蜂血淋巴中含有8种多胺,其中腐胺(Put)、亚精胺(Spd)、精胺(Spm)、尸胺(Cad)为普遍存在的多胺,其发育的不同阶段,多胺的种类和含量均发生变化;在滞育预蛹的血淋巴中Spm一直保持较高的含量,并在整个滞育期间存在2个峰值;在滞育的前5个月中血淋巴中不存在Spd,之后Spd突然出现,且含量迅速升高;Cad的代谢较平稳,在化蛹前稍有下降;Put的含量除在滞育后3个月左右有较大的峰值外,其余阶段的含量均较高,并在化蛹前有升高的趋势.总之,多胺可能参与鞭角华扁叶蜂预蛹滞育过程. 相似文献
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《Agricultural Systems》1986,22(2):109-125
Some key practical issues in improving the economic impact of farming systems research are examined. Following some general background on how such research evolved, these issues are treated with respect to its three main stages.With the ex ante stage the needs of securing representativeness of the target area and of benchmarking the wider initial situation, including economic, social and agroclimatic features, are emphasized. With the ongoing stage, the importance of using suitable partial budgeting techniques is stressed. With the ex post stage, an assessment of wider technological and economic effects is called for, together with the identification of enabling factors and constraints in technological progress.The adjustment of the farming systems research process itself is finally considered, and the desirability of simplifying the process, further training junior field-level researchers and securing better interaction between workers at the various research levels, is highlighted. 相似文献
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《Agricultural Systems》1986,21(4):279-310
Homegardens represent land use systems involving deliberate management of multipurpose trees and shrubs in intimate association with annual and perennial agricultural crops and, invariably, livestock, within the compounds of individual houses, the whole crop-tree-animal unit being intensively managed by family labour. Known by different names in various places, these agroforestry systems are common in all ecological regions of the tropics and subtropics, especially in humid lowlands with high population density.An analysis of the structural and functional aspects of ten selected homegarden systems from different ecological and geographical regions shows that the average size of the homegarden units is less than 0·5 ha; yet they are composed of a large number of woody and herbaceous species, carefully structured to form 3–5 vertical canopy strata, with each component having a specific place, as well as function.Food production is the primary function of most homegardens, the vast majority of them being subsistence production systems. While there is a remarkable similarity among the different homegardens with respect to the type and nature of the herbaceous crops, the nature of woody perennials varies, depending on environmental and ecological factors. In general, most woody components produce fruits or other types of food in addition to other outputs such as fuelwood, timber, etc. These various food products provide a substantial proportion of nutritive and energy requirements of the local diet. Moreover, the species diversity and varying production cycles of the different components ensure continuous production throughout the year from the homegarden unit.Little or no research has been done to improve homegarden systems. Structural complexity, species diversity, multiple output nature, tremendous variability from farm to farm, etc., are some of the main characteristics that make the homegardens extremely difficult models to work with according to the currently available research procedures. 相似文献