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以辣根为原料,筛选不同的水解工艺,研究硫代葡萄糖苷水解为异硫氰酸酯(ITCs)的转化率.结果表明,在温度40℃、pH值7、料液比1∶20(g∶mL)的条件下,水中加入Vc0.2%(以辣根粉计),水解2h,水蒸气蒸馏法得到的异硫氰酸酯质量分数最高(88.71%),经GC-MS、IR、1HNMR、13CNMR和MS鉴定为苯乙基异硫氰酸酯,经检索该化合物在辣根中首次分离鉴定.而采用二氯甲烷和水为1∶2的体积比的水解液水解辣根粉得到的异硫氰酸酯为苯乙基异硫氰酸酯(54.89%)和烯丙基异硫氰酸酯(5.18%).采用黑芥子酶酶解硫代葡萄糖苷法,水解产物中苯乙基异硫氰酸酯含量最低(10.67%). 相似文献
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I RIETHMULLER-HAAGE L BASTIAANS C KEMPENAAR† V SMUTNY‡ & MJ KROPFF 《Weed Research》2007,47(5):415-424
To evaluate the effect of pre‐spraying growing conditions on herbicide efficacy, two years of experimentation were conducted in which Persicaria maculosa plants were exposed to different light intensities for 1–4 days before metribuzin treatment. Specific leaf area, rather than plant growth rate or plant size, was the only parameter that correlated well with herbicide efficacy in both years of experimentation. The negative relationship between the ED50 and the specific leaf area indicates that leaf characteristics might be an important determinant of herbicide efficacy, for instance through an effect on herbicide uptake. In the third year of experimentation this hypothesis was further investigated by raising six cohorts of weed plants at a 1‐week interval and thus exposing them to a range of weather conditions. Clear relationships between uptake and herbicide efficacy were found for a combination of four plant species (Solanum nigrum, Senecio vulgaris, Chenopodium album and Brassica napus) and two herbicides (phenmedipham and bentazone). For phenmedipham, uptake was negatively correlated with global radiation and positively correlated with relative humidity. For the herbicide bentazone the opposite was found. These results were not species‐specific. This study shows the importance of the sensitivity of herbicide × species combinations and indicates that pre‐spraying weather information is relevant for the development of reduced dose rate recommendations. 相似文献
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Cattle deaths in two contemporaneous incidents were attributed to acute intoxication with Persicaria lapathifolia and P. orientalis when the plants were under heat and moisture stress. To our knowledge this is the first confirmed report of acute, fatal hepatic necrosis associated with ingestion of these plants. 相似文献
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Over the past four decades potato has emerged as the most important cash crop for Bhutanese mountain farmers. Farmers' feedback and field observations were used to describe weed populations, weed management and weed-production environment-yield interactions in small-holder potato production systems. Weed species across a range of locations in order of declining importance are: Persicaria runcinata , Galium aparine , Fagopyrum dibotrys , Digitaria ciliaris , Commelina maculata , Galinsoga parviflora and Persicaria nepalensis. The same species were common in the traditional buckwheat and maize production systems as well as the more recently established potato production systems. Limited associations between soil properties, management practices, weed species abundance and potato yield were observed. Species emerging as potential problem weeds, especially P. runcinata and F. dibotrys , are little known outside the Himalayan region. The increase in P. runcinata , reported by 42% of the respondents, was attributed to the use of metribuzin, cutting of rhizomes by plough or spade, high inputs of fertiliser and continuous cultivation of potato by 61%, 17%, 9%, 9% and 4% of respondents respectively. Metribuzin application reduced growth of P. runcinata but could not fully control it. Metribuzin is an effective and affordable weed management tool for small-holder potato farmers, but perennial weed species need further research, combining mechanical and chemical methods with cropping strategies. 相似文献
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