共查询到20条相似文献，搜索用时 31 毫秒
1.
Summary Weeds cause yield losses and reductions in crop quality. Prior to the introduction of selective herbicides, the drudgery of manual weeding forced farmers to adhere to a suit of weed management tactics by carefully combining crop rotation, appropriate tillage and fallow systems. The introduction of selective herbicides in the late 1940s and the constant flow of new herbicides in the succeeding decades provided farmers with a new tool, ‘the chemical hoe’, putting them in a position to consider weed control more independently of the crop production system than hitherto. The reliance on herbicides for weed control, however, resulted in shifts in the weed flora and the selection of herbicide‐resistant biotypes. In the 1980s, the public concern about side‐effects of herbicides on the environment and human health resulted in increasingly strict registration requirements and, in some countries, political initiatives to reduce the use of pesticides were launched. Today, the number of new herbicides being introduced has decreased significantly and integrated weed management has become the guiding concept. Farmers also have the option of growing herbicide‐resistant crops where the biology of the crop has been adapted to tolerate herbicides considered safe to humans and environmentally benign. This paper discusses some of the recent developments in herbicide discovery, technology and fate, and sketches important future developments. 相似文献
2.
As herbicide‐resistant weeds have spread in the agricultural fields of grain‐exporting countries, their seeds could be introduced into other countries as contaminants in imported grain. The spread of resistance genes through seed and pollen can cause significant economic loss. In order to assess the extent of the problem, we investigated the contamination by herbicide‐resistant annual ryegrass (Lolium rigidum) of wheat imported from Western Australia into Japan. Annual ryegrass seeds were recovered from wheat shipments and seed bioassays were conducted to identify resistance to the herbicides that are commonly used in Australia: diclofop‐methyl, sethoxydim, chlorsulfuron, and glyphosate. Nearly 4500 ryegrass seeds were detected in 20 kg of wheat that was imported in both 2006 and 2007. About 35% and 15% of the seeds were resistant to diclofop‐methyl, 5% and 6% were resistant to sethoxydim, and 56% and 60% were resistant to chlorsulfuron in 2006 and 2007, respectively. None was resistant to glyphosate in either year. As the contamination of crops by herbicide‐resistant weeds is probably a common phenomenon, the monitoring of incoming grain shipments is necessary to stem the further spread of herbicide‐resistant weeds into importing countries. 相似文献
3.
Elzbieta G Magnucka Yoshikatsu Suzuki Stanislaw J Pietr Arkadiusz Kozubek Robert Zarnowski 《Pest management science》2009,65(10):1065-1070
BACKGROUND: Cycloate inhibits the biosynthesis of very‐long‐chain fatty acids, the essential constituents of plant waxes and suberin. Fatty acids also serve as precursors of aliphatic carbon chains in resorcinolic lipids, which play a fundamental role in the plant defence system against fungal pathogens. In this study, the effect of cycloate on the biosynthesis of 5‐n‐alkylresorcinols in rye seedlings (Secale cereale L.) grown under various light and thermal conditions was examined. RESULTS: The content of alkylresorcinols biosynthesised in rye was generally increased by the herbicide in both green and etiolated plants. The presence of cycloate also affected patterns of alkylresorcinol homologues in plants grown at 15 and 22 °C; very‐long‐side‐chain compounds were less abundant, whereas both short‐chain saturated and unsaturated homologues were generally accumulated. No cycloate‐related effects caused by homologue pattern modifications were observed at elevated temperature. CONCLUSION: This study extends present understanding of the mode of action of thiocarbamate herbicides. Cycloate markedly affected the biosynthesis of very‐long‐side‐chain resorcinolic lipids in rye seedlings, confirming the existence of parallels in both fatty acid and alkylresorcinol biosynthetic pathways. The observed cycloate‐driven accumulation of 5‐n‐alkylresorcinols may improve the resistance of cereals to infections caused by microbial pathogens. Copyright © 2009 Society of Chemical Industry 相似文献
4.
5.
Intensive herbicide use has selected for constitutively elevated levels of stress‐responsive mRNAs and proteins in multiple herbicide‐resistant Avena fatua L 
下载免费PDF全文
下载免费PDF全文 Barbara K Keith Erin E Burns Brian Bothner Charles C Carey Aurélien J Mazurie Jonathan K Hilmer Sezgi Biyiklioglu Hikmet Budak William E Dyer 《Pest management science》2017,73(11):2267-2281
6.
In an ongoing effort to investigate the mechanism of auxinic herbicide resistance in Kochia scoparia (kochia), polymerase chain reaction‐based cDNA suppression subtractive hybridization was used to identify genes that are differentially expressed between dicamba‐resistant (HRd) and dicamba‐susceptible (S1) kochia biotypes in response to herbicide treatment. Both the HRd and S1 adaptor‐ligated cDNAs were used in separate hybridizations in order to generate biotype‐specific clones. A total of 710 cDNAs, representing putative differentially expressed mRNAs, were isolated and subjected to further screening. The false‐positive cDNAs were removed by conducting two colony hybridizations and at least one Northern hybridization. Differential or biotype‐specific expression was confirmed for six clones each from the HRd and S1 plants. The S1‐related genes were constitutively expressed at higher levels than in the HRd plants, but none had significant sequence similarity to known genes. Among the HRd‐related genes, HRd‐88 had 42% amino acid sequence identity to a conserved domain within thiol peptidases, which might be involved in auxin‐regulated gene expression. The constitutively expressed and inducible (by the dicamba treatment) HRd‐39 had 40% identity and 60% similarity to a domain from the Fe(II)/α‐ketoglutarate‐dependent hydroxylase superfamily. The HRd‐39 gene product had the characteristics of an enzyme that is able to detoxify dicamba via oxidative hydroxylation and thus its overexpression might confer the dicamba resistance phenotype. 相似文献
7.
8.
9.
10.
A failure of acetyl‐coenzyme A carboxylase (ACCase)‐inhibiting herbicides to control a population of Hordeum leporinum Link (barleygrass) occurred following eight applications of these herbicides in both crops and pastures. This population was 7.6‐fold resistant to fluazifop‐P‐butyl compared with standard susceptible populations. The population was between 3.6‐ and 3.8‐fold resistant to other ACCase‐inhibiting herbicides, except butroxydim to which it was susceptible. ACCase extracted from resistant plants and assayed in the presence of herbicides in vitro was susceptible to fluazifop acid and other aryloxyphenoxypropanoate herbicides, but was 4‐fold less sensitive to sethoxydim compared with ACCase from susceptible plants. Resistant plants metabolised fluazifop acid about 1.3‐fold more rapidly compared with susceptible plants; however, sethoxydim was metabolised equally in both populations. Resistance to fluazifop‐P‐butyl and other aryloxyphenoxypropanoate herbicides may be the result of increased herbicide detoxification, whereas resistance to sethoxydim appears to be due to a modified target enzyme. Herbicide resistance in this population is unusual in that different mechanisms appear to confer resistance to the aryloxyphenoxypropanoate and cyclohexanedione herbicides. © 2000 Society of Chemical Industry 相似文献
11.
12.
13.
Segregation of non‐target‐site resistance to herbicides in multiple‐resistant Alopecurus myosuroides plants 下载免费PDF全文
下载免费PDF全文 Non‐target‐site resistance (NTSR) comprises a set of mechanisms conferring resistance to multiple modes of action. Investigation of the number of loci involved in NTSR will aid in the understanding of these resistance mechanisms. Therefore, six different multiple herbicide‐resistant Alopecurus myosuroides plants with different herbicide history were crossed in two generations with a susceptible wild type. Seeds from the backcrossing generation were studied for their segregation rate for resistance to five herbicides with four different modes of action (HRAC groups C2, A, B and K3). Taking into account that NTSR is a set of quantitative traits, the numbers of loci controlling NTSR were estimated using a normal mixture model fitted by the NLMIXED procedure of SAS. Each herbicide was controlled by a different number of loci comparing the six plants. In most of the cases, chlorotoluron resistance was controlled by one locus, whereas resistance to fenoxaprop‐P‐ethyl needed one or two loci. Resistance to pinoxaden was in all plants conferred by two loci. Cross‐resistance of fenoxaprop‐P‐ethyl and pinoxaden was found in all backcrossings, indicating that at least one of the two loci is responsible for both resistances. Resistance to mesosulfuron + iodosulfuron was conferred by a minimum of two loci. Results indicated that a minimum of five different loci can be involved in a multiple NTSR plant. Furthermore, the plant‐specific accumulation of NTSR loci was demonstrated. Such behaviour should be taken into account when evaluating the development and further spread of herbicide resistance. 相似文献
14.
15.
16.
17.
Herbicide‐resistant populations of Alopecurus myosuroides Huds (black‐grass) have become widespread throughout the UK since the early 1980s. Clear evidence suggests that more than one resistance mechanism exists, and glutathione S‐transferases (GSTs) have been implicated in resistance due to enhanced metabolism. This study reports the determination of GST activity in four UK black‐grass populations from field sites situated in the East Midlands. Data demonstrate that, as untreated plants in the field mature, there is an accompanying natural elevation of GST activity with natural environmental changes from winter to spring. We speculate that this endogenous change in enzyme activity with plant development in the field contributes to reduced efficacy of some graminicides applied in the spring. These observations are discussed in relation to predicting herbicide efficacy to achieve maximum control of this important grass weed. © 2001 Society of Chemical Industry 相似文献
18.
19.
20.
Fifty years of herbicide research: comparing the discovery of trifluralin and halauxifen‐methyl 下载免费PDF全文
下载免费PDF全文 Fifty years separate the commercialization of the herbicides trifluralin and halauxifen‐methyl. Despite the vast degree of technological change that occurred over that time frame, some aspects of their discovery stories are remarkably similar. For example, both herbicides were prepared very early in the iterative discovery process and both were developed from known lead compound structures by hypothesis‐driven research efforts without the use of in vitro assays or computer‐aided molecular design. However, there are aspects of the halauxifen‐methyl and trifluralin discovery stories that are substantially different. For example, the chemical technology required for the cost‐effective production of halauxifen‐methyl simply did not exist just two decades prior to its commercial launch. By contrast, the chemical technology required for the cost‐effective production of trifluralin was reported in the chemical literature more than two decades prior to its commercial launch. In addition, changes in regulatory environment since the early 1960s ensured that their respective discovery to commercial launch stories would also differ in substantial ways. Ultimately, the time and cost required to develop and register halauxifen‐methyl demanded a global initial business case while the lower registration hurdles that trifluralin cleared enabled a narrow initial business case mainly focused on the USA. © 2017 Society of Chemical Industry 相似文献