共查询到20条相似文献,搜索用时 109 毫秒
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有关农药的多方面研究,包括构效关系研究、抗药性机制、遗传方式、比较毒力和代谢都离不开室内生测。由于变量在实验室条件下严格受到控制,因此以上述研究为目的的生物测定,其可靠性通常是靠大样方和多重复来保证。然而,为预测农药田间效果,室内生测尽管有很大改进,但一直尚存不足。使用大样方和多重复并不能保证这种预测的价值。 相似文献
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以氯虫苯甲酰胺为主要研究对象,选择不同类型的对照药剂,室内以小菜蛾、甜菜夜蛾、二化螟等重要鳞翅目害虫为生测靶标,比较杀虫毒力;田间以小菜蛾、稻纵卷叶螟为防治对象,比较田间防效。初步研究了氯虫苯甲酰胺室内毒力与田间防效的相关性,为该类化合物的创制优化和进一步研发提供了有益参考。 相似文献
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John A. Byers 《Journal of chemical ecology》1992,18(9):1603-1621
Studies of chemical ecology of an organism are founded on the isolation and identification of a semiochemical, often comprised of two or more synergistic compounds (each Synergist alone has little activity, but presented together they are bioactive). Chromatographie fractionation and bioassay methods of binary splitting, additive combination, and subtractive combination are compared for efficiency in isolating synergists. Formulas are derived for the latter two methods that calculate the expected number of bioassay tests required for isolation of from two to five synergists from biological extracts with any number of compounds, depending on the number of initial (major) Chromatographic fractions. A computer program based on the formulas demonstrates the superiority of the subtractive-combination method. Simulations with the program were used to determine the optimal number of initial fractions for the additive- and subtractive-combination methods when isolating two to five synergists from extracts of from 25 to 1200 compounds. Methods of bioassay, isolation, identification, and field testing of semiochemicals are discussed. 相似文献
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Farnier K Bengtsson M Becher PG Witzell J Witzgall P Manduríc S 《Journal of chemical ecology》2012,38(6):795-801
Potato cyst nematodes (PCNs) are a major pest of solanaceous crops such as potatoes, tomatoes, and eggplants and have been widely studied over the last 30 years, with the majority of earlier studies focusing on the identification of natural hatching factors. As a novel approach, we focused instead on chemicals involved in nematode orientation towards its host plant. A new dual choice sand bioassay was designed to study nematode responses to potato root exudates (PRE). This bioassay, conducted together with a traditional hatching bioassay, showed that biologically active compounds that induce both hatching and attraction of PCNs can be collected by water extraction of incised potato roots. Furthermore, our results demonstrated that PCN also were attracted by potato root volatiles. Further work is needed to fully understand how PCNs use host plant chemical cues to orientate towards hosts. Nevertheless, the simple attraction assay used in this study provides an important tool for the identification of host-emitted attractants. 相似文献
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Behavioral and electrophysiological studies with live intact larvae and larval rinses of the red imported fire ant,Solenopsis invicta Buren, give undeniable evidence of a volatile material associated with the larvae of the ant that is capable of eliciting a response from brood-tending workers. In a Y-tube bioassay, worker ants were attracted equally to an airstream blown over sibling larvae or heterocolonial larvae. Workers were also attracted to a rinse of the larvae in a spot bioassay, aggregated about a piece of surrogate brood in another bioassay, and retrieved surrogate brood treated with the rinse material. A dose-response curve constructed from electroantennograms of workers revealed a receptor response of 1–100 brood equivalents. 相似文献
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Crops that control weeds by root exudation of allelochemicals are receiving increased attention, and there are efforts to breed allelopathic cultivars in several crops. The genetic improvement of allelopathic traits is based upon parental germ plasm with high allelopathic activity. Identification of allelopathic germplasm is done in laboratory screening bioassays, but experimental protocols are limited. We developed a fast and reliable laboratory screening bioassay for grain crops that includes dose-response considerations as an integral part of the experimental design. The bioassay was conducted in hydroponic culture, and a range of experiments with 2-(3H)-benzoxazolinone (BOA), an allelochemical of several grain crops, was carried out to define the basic protocol. Because of its sensitivity to BOA, Sinapis alba L. was selected as the receiver species. BOA affected growth (fresh weight and length of shoot and root), enzyme activities (ascorbate peroxidase, catalase, glutathione S-transferase, peroxidase, phenylalanine ammonia-lyase), and chlorophyll fluorescence, whereby root length was the most reliable response parameter. BOA sensitivity was dependent on nutrients for all parameters measured, and, thus, no nutrients were added. A set of experiments with Secale cereale L. and Triticum aestivum L. as donor species was carried out to optimize the protocol. Light and pH were eliminated as primary causes for the observed inhibition. The proposed bioassay has several methodological advantages over current bioassays. 相似文献
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噻虫啉对蚜虫杀虫活性及田间药效评价 总被引:1,自引:0,他引:1
采用农药生物测定标准操作程序(SOP)比较测定了噻虫啉和吡虫啉对蚜虫的毒力。室内生物测定结果表明,噻虫啉和吡虫啉对蚜虫有良好的杀虫活性,其毒力平均LC50分别为1.24mg/L和1.45mg/L。田间小区试验结果表明,噻虫啉对蚜虫表现出良好的防治效果,有效用量为3.36、6.72、10.08g/667m2时,药后1~10d的防治效果分别为85.82%~89.55%、89.25%~92.08%、92.43%~96.34%,好于剂量相当的吡虫啉的防治效果。 相似文献
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A large variety of secondary metabolites that can inhibit germination and/or seedling growth are produced by plants in low quantities. The objective of this study was to develop a bioassay capable of reliably assessing reductions in germination percentage and seedling length of small-seeded plant species caused by exposure to minute quantities of these compounds. The germination and growth of alfalfa (Medicago saliva), annual ryegrass (Lolium multiflorum), and velvetleaf (Abutilon theophrasti) were evaluated against six known phytotoxins from five chemical classes; cinmethylin (a herbicidal cineole derivative) was selected as a comparison standard. Each phytotoxin, dissolved in a suitable organic solvent, was placed on water-agar in small tissue culture wells. After the solvent evaporated, imbibed seeds were placed on the agar; after three days, germination percentages and seedling lengths were measured. Compared to a commonly used filter paper procedure, this modified agar bioassay required smaller quantities of compound per seed for comparable bioassay results. This bioassay also readily permitted the measurement of seedling length, a more sensitive indicator of phytotoxicity than germination. Seedling length decreased sigmoidally as the toxin concentration increased logarithmically. Phytotoxicity was a function of both compound and plant species. Cinmethylin, a grass herbicide, reduced the length of annual ryegrass seedlings by 90–100%, whereas that of alfalfa and velvetleaf was inhibited slightly. The agar bioassay facilitated the rapid and reliable testing of slightly water-soluble compounds, requiring only minute quantities of each compound to give reproducible results.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned. 相似文献