Effects of a sulfonylurea herbicide on soil microarthropods

 The short-term effects on soil microarthropods of the herbicide triasulfuron, belonging to the chemical class of sulfonylureas, were evaluated in two fields which had never been treated with sulfonylureas, and were cultivated with winter wheat. In particular, the effects of single applications at rates corresponding to two- (rate 2) and sixfold (rate 6) the recommended agricultural rate (7.5 g active ingredient ha^–1) were analysed and compared with controls. The changes in the populations of the main groups of microarthropods were evaluated. Rate 2 had very low effects, whereas rate 6 produced a significant decrease in the number of microarthropods, Acarina and Collembola in the surface soil layer (0–7.5 cm). The Collembola were analysed at the species level. Statistical analysis revealed significant differences only for a few species, and only after treatment with the highest rate of triasulfuron. Finally, the results of the field tests were compared to those of laboratory tests carried out previously, which examined the effects of the same herbicide on a collembolan species. Received: 11 November 1998     

玉米单倍体加倍方法研究进展

主要综述了近年来玉米单倍体加倍方法的最新研究进展。自然加倍法和以秋水仙素及除草剂为加倍剂的化学加倍法是人们研究较多的加倍方法。     

Natural products as sources for new mechanisms of herbicidal action

New mechanisms of action for herbicides are highly desirable to fight evolution of resistance in weeds, to create or exploit unique market niches, and to cope with new regulatory legislation. Comparison of the known molecular target sites of synthetic herbicides and natural phytotoxins reveals that there is little redundancy. Comparatively little effort has been expended on determination of the sites of action of phytotoxins from natural sources, suggesting that intensive study of these molecules will reveal many more novel mechanisms of action. Examples of natural products that inhibit unexploited steps in the amino acid, nucleic acid, and other biosynthetic pathways are given. AAL-toxin, hydantocidin, and various plant-derived terpenoids are discussed. Strategies and potential pitfalls of using natural products as leads for new herbicide classes are summarized.     

康县牡丹园草的种类及其除草剂的选择

牡丹在我国有着很大的药用价值和观赏价值。合理地除去牡丹园的杂草让牡丹幼苗更好地生长是一项重要的工作。对康县牡丹园的杂草种类进行调研和分类,有针对性地选择相关除草剂,具有一定的除草功效。     

Metabolism of the herbicides chlorotoluron, diuron, linuron, simazine, and atrazine by CYP1A9 and CYP1C1 from Japanese eel (Anguilla japonica)

Through the use of a number of bioconversion experiments we demonstrated that P450 proteins (CYP1A9 and CYP1C1) from Japanese eel (Anguilla japonica) metabolized a number of herbicides and the drug phenacetin. We performed bioconversion experiments in which substrates were added directly to incubation medium. The resulting metabolites were extracted and analyzed by high-performance liquid chromatography. Proteins CYP1A9 and CYP1C1 metabolized 50 nmol of the drug phenacetin to yield 12.1 and 1.1 nmol of product (acetaminophen), respectively. Further incubation of CYP1A9 with 50 nmol of the herbicides chlorotoluron, diuron, linuron, simazine, or atrazine yielded 16.5, 18.5, 7.3, 1.6, or 0.8 nmol of product, respectively. CYP1C1 also metabolized linuron, diuron, and simazine yield 5.4, 4.6, or 0.7 nmol of product, respectively. Next, polyclonal antibody was isolated by immunizing with two conjugated-peptides (amino acid residues 272–290 and 294–310) of CYP1A9. This antibody did not recognize human CYP1A2 or CYP1C1. Western blotting using the antibody revealed one band in the livers of Japanese eel and tilapia (Oreochromis niloticus). Theses results suggest that CYP1A9 and CYP1C1 metabolize herbicides, and that CYP1A9 is an useful biomarker of contamination when detected with this antibody.     

除草剂现锄对国槐生理生化影响的研究

旨在研究现锄农田常用除草剂对国槐苗生长产生抑制或促进作用的生理生化机制,并力求从中得出既能够有效杀死杂草又对国槐苗生长基本无影响的浓度。经过对现锄高、中、低三个浓度处理下国槐苗新梢生长量、叶绿素含量、丙二醛含量及膜相对透性的测定,并进行数据统计,我们总结出现锄对国槐生理生化的影响。试验结果表明:高浓度、中浓度的现锄对国槐生长发育有一定的抑制作用;并指出在国槐苗圃进行化学除草时,现锄这种除草剂使用浓度为0.25 g.kg-1,并且要加强保护措施,以免药液溅到树叶上。     

除草剂在杨树、柳树苗圃中的应用试验

试验表明采用使它隆＋高效盖草能除草剂组合，在杨树、柳树当年扦插苗和截干苗圃中低位定向喷施，用药后30d，对双子叶阔叶杂草和单子叶禾本科杂草防除效果为92．49％以上，对苗木生长无影响。较人工除草省时、省工，成本低，见效快。     

不同除草剂对间作玉米大豆的药害及除草效果

采用盆栽方法模拟玉米大豆间作模式栽培,选用10种土壤处理除草剂和13种茎叶处理除草剂,研究不同除草剂对玉米、大豆生长发育的影响及杂草的防效。结果表明:通过试验筛选出药害轻或药害后能恢复的5种土壤处理剂和5种茎叶处理剂,5种土壤处理剂分别为二甲戊灵、精异丙甲草胺、扑·乙·滴丁酯、乙·嗪·滴丁酯、嗪酮·乙草胺,5种茎叶处理剂分别为灭草松、噻吩磺隆、双氟·唑嘧胺、氟醚·灭草松、咪唑乙烟酸。二甲戊灵和嗪酮·乙草胺的土壤处理中玉米、大豆的株高、茎粗和干物重与清水对照差异不显著,对玉米、大豆安全,株防效分别为60.58%和60.58%,鲜重防效分别为67.12%和55.35%。精异丙甲草胺影响间作玉米的株高和茎粗,但不影响玉米干物质的积累,株防效和鲜重防效分别为71.96%和78.83%,高于其它除草剂。茎叶处理中灭草松安对玉米、大豆的株高、茎粗和干物重与清水对照差异不显著,株防效为52.7%,低于其它除草剂。噻吩磺隆处理后,玉米、大豆的株高受到抑制,茎增粗,但药害能恢复,且除草效果高于其它处理,株防效和鲜重防效分别为73.88%和96.1%。土壤处理剂二甲戊灵和茎叶处理剂灭草松对玉米、大豆更安全,土壤处理剂精异丙甲草胺和茎叶处理剂噻吩磺隆除草效果更好。     

取代脲类和二苯基醚类除草剂的表面光化学相互作用研究

应用高效薄层析方法研究了１１种取代脲类除草剂和３种二苯基醚类除草剂自然光源下薄态的光化学相互作用。结果表明,２类除草剂在光上可相互产生强烈的光敏化效应,１１种脲昌剂大多数不稳定性较强,分别与消草醚事照光后,光解迅速加强。消草醚地１１种奕除草剂４ｈ光敏效率分别达８０．４％至５５．８９％。３种醚类除草剂对绿麦隆的光敏疚炎消草醚〉治草醚〉虎威。１１种脲类除草剂对消草醚均种醚类除草剂对缘麦降珠光敏交谈 消     

大豆田主要杂草的综合防除及除草剂安全合理施用技术

根据最新研究结果，系统阐述了我国大豆田杂草的种类分布与危害、农业防除措施、化学防除技术以及大豆田常用除草剂的安全性与混合使用技术等，对我国大豆田杂草的防除具有重要的理论价值和实际指导意义。