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1.
Two major weeds in rice in the Philippines, Sphenochlea zeylanica Gaertn. and Echinochloa crus‐galli (L.) Beauv., are controlled with chemical and cultural methods. In the 1980s, after >10 years of continuous use of 2,4‐D, S. zeylanica evolved resistance to the chemical in those rice fields that had been treated with 2,4‐D once or twice every cropping season. In the 1990s, E. crus‐galli evolved resistance to butachlor and propanil in rice monocrop areas where both herbicides were used continuously for 7–9 years. Rice farmers continue to use 2,4‐D, butachlor and propanil extensively and are often unaware of herbicide resistance or the potential for cross‐resistance, its causes or its implications. In order to control herbicide‐resistant E. crus‐galli, farmers are shifting to locally available herbicides with different modes of action, such as bispyribac, an acetolactate synthase inhibitor, and cyhalofop, an acetyl coenzyme A carboxylase inhibitor. Follow‐up manual weeding or rotary weeding after herbicide spraying, a common farmers’ practice, removes the susceptible and resistant biotypes and could help to delay or prevent the evolution of resistance. Although the resistance mechanisms of both weeds are not determined yet, they could be related to enhanced degradation that is similar to the mechanisms that are shown by the resistant biotypes in other countries.  相似文献   

2.
The effects of herbicide dose on rice‐weed competition were investigated to develop a combined model, which can be utilised to estimate an optimum herbicide dose for a given weed density in paddy rice cultivation. Field studies were conducted in Suwon for rice‐Echinochloa crus‐galli competition and Iksan for rice‐Eleocharis kuroguwai during 2007. The competitive effect of the weeds E. crus‐galli and E. kuroguwai decreased with increasing doses of flucetosulfuron and azimsulfuron, respectively, in the same manner as the standard dose–response curve. The combination of the rectangular hyperbolic model and the standard dose–response curve adequately described the complex effects of herbicide dose and weed competition on rice yield. Parameter estimates were used with the model to predict rice yield and estimate the doses of flucetosulfuron and azimsulfuron required to restrict rice yield loss caused by E. crus‐galli and E. kuroguwai, respectively, to an acceptable level. For a rice yield of 5.0 t ha?1, the model recommended flucetosulfuron doses of 8.7, 13.4 and 20.1 g a.i. ha?1 when infested with E. crus‐galli at 12, 24 and 48 plants m?2 respectively. For a rice yield of 5.2 t ha?1, the model recommended azimsulfuron doses of 3.9, 7.5 and 12.6 g a.i. ha?1 when infested with E. kuroguwai at 24, 48 and 96 plants m?2 respectively. The theoretical outputs of the combined model appear robust and indicate there are opportunities for reduced herbicide use in the field. These now require evaluation under field conditions.  相似文献   

3.
G Li  S G Wu  R X Yu  T Cang  L P Chen  X P Zhao  L M Cai  C X Wu 《Weed Research》2013,53(5):314-321
Plant glutathione S‐transferase (GST) forms a major part of the herbicide detoxification enzyme network in plants. A GST cDNA was isolated from Echinochloa crus‐galli and characterised. The gene, designated EcGST1 (E. crus‐galli GeneBank no: JX518596 ), has a 684 bp open reading frame predicted to encode a 25 kD protein. Sequence alignment showed that EcGST1 is a GST homologue. Its expression in response to quinclorac treatment was monitored in seedlings (leaves and roots) and adult plants (leaves, roots, stems and seeds) of quinclorac‐resistant (R) and susceptible (S) biotypes of E. crus‐galli. EcGST1 expression was 1.5–3 times greater in the R plants than in the S plants. However, after exposure to quinclorac, the difference in the expression levels of EcGST1 in R plants, compared with S plants, increased to a ratio of 6–10. Enhanced EcGST1 levels should enable greater quinclorac detoxification following quinclorac stimulation in R plants. GST‐based metabolism may be partially responsible for resistance to quinclorac in E. crus‐galli. The results suggest a new resistance mechanism for this R biotype in Chinese rice fields.  相似文献   

4.
Abstract

Two morphological variants of Echinochloa crus‐galli were collected from rice fields of an area in Greece where rice has been grown for over a decade and growers have recently been complaining about reduced effectiveness of propanil. Seedling response of the two variants to propanil was compared with that of E. crus‐galli collected from vegetable fields in another area where rice has never been grown. Initial contact toxicity of propanil was similar in all collections. Growth inhibition thereafter was clearly different, resulting in death of the E. crus‐galli from vegetables but not of the E. crus‐galli from rice. The latter could overcome initial toxicity and resume growth at 8 kg/ha of propanil, whereas the former was killed at 2–4 kg/ha. Prevalence of E. crus‐galli forms of higher tolerance resulting from selection through rice husbandry and/or repeated use of propanil may account for the reduced effectiveness of propanil in the area of intensive rice growing.  相似文献   

5.
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6.
BACKGROUND: Fifteen novel derivatives of D‐DIBOA, including aromatic ring modifications and the addition of side chains in positions C‐2 and N‐4, had previously been synthesised and their phytotoxicity on standard target species (STS) evaluated. This strategy combined steric, electronic, solubility and lipophilicity requirements to achieve the maximum phytotoxic activity. An evaluation of the bioactivity of these compounds on the systems Oryza sativa–Echinochloa crus‐galli and Triticum aestivum–Avena fatua is reported here. RESULTS: All compounds showed inhibition profiles on the two species Echinochloa crus‐galli (L.) Beauv. and Avena fatua L. The most marked effects were caused by 6F‐4Pr‐D‐DIBOA, 6F‐4Val‐D‐DIBOA, 6Cl‐4Pr‐D‐DIBOA and 6Cl‐4Val‐D‐DIBOA. The IC50 values for the systems Echinochloa crus‐galli–Oryza sativa and Avena fatua–Triticum aestivum for all compounds were compared. The compound that showed the greatest selectivity for the system Echinochloa crus‐galli–Oryza sativa was 8Cl‐4Pr‐D‐DIBOA, which was 15 times more selective than the commercial herbicide propanil (Cotanil‐35). With regard to the system Avena fatua–Triticum aestivum, the compounds that showed the highest selectivities were 8Cl‐4Val‐D‐DIBOA and 6F‐4Pr‐D‐DIBOA. The results obtained for 6F‐4Pr‐D‐DIBOA are of great interest because of the high phytotoxicity to Avena fatua (IC50 = 6 µM , r2 = 0.9616). CONCLUSION: The in vitro phytotoxicity profiles and selectivities shown by the compounds described here make them candidates for higher‐level studies. 8Cl‐4Pr‐D‐DIBOA for the system Echinochloa crus‐galli‐Oryza sativa and 6F‐4Pr‐D‐DIBOA for Avena fatua‐Triticum aestivum were the most interesting compounds. Copyright © 2010 Society of Chemical Industry  相似文献   

7.
The intensive use of the acetolactate synthase (ALS)‐inhibiting herbicides, imazethapyr, penoxsulam and bispyribac‐sodium, in imidazolinone‐resistant (Clearfield) rice increases the risk of the evolution of ALS‐resistant barnyardgrass. In 2009, imazethapyr failed to control barnyardgrass that was collected from a field in Arkansas, USA, following the failure of the herbicide in 2008. A greenhouse experiment was conducted to confirm and document the level of resistance of the biotype against three ALS‐inhibiting herbicides that currently are labeled in rice. The level of control of the resistant biotype at the labeled rate of bispyribac‐sodium of 35 g ai ha?1 was 10%, penoxsulam at 22 g ai ha?1 was 0% and imazethapyr at 70 g ai ha?1 was 25%. The level of mortality of the susceptible biotype was 100% with all the herbicides at the labeled rate. The dose needed to kill 50% of the resistant plants was 49 g ha?1 of bispyribac‐sodium, 254 g ha?1 of penoxsulam and 170 g ha?1 of imazethapyr. For the susceptible biotype, bispyribac‐sodium at 6 g ha?1, penoxsulam at 10 g ha?1 and imazethapyr at 12 g ha?1 killed 50% of the treated plants. Based on these findings, it was confirmed that a barnyardgrass population has evolved cross‐resistance to three ALS‐inhibiting herbicides in rice culture in Arkansas. Furthermore, an experiment was conducted to determine if the ALS‐resistant biotype could be controlled using other mechanisms of action. The results indicated that propanil, a photosystem II inhibitor, and quinclorac, a synthetic auxin, failed to control the resistant biotype at the labeled rates, whereas all the other evaluated herbicides provided effective control of both biotypes.  相似文献   

8.
Abstract

In northern Queensland, the addition of 2,4,5‐T butyl ester was found to be unnecessary to maintain the control of Echinochloa colona (L.) Link and Cyperus Iria L. In dry seeded rice when propanil rates were reduced below the registered rate of 4 kg a.i. ha?1. Adequate weed control was obtained with 1.3 kg a.i. ha?1 propanil alone. No adverse effects on rice yield were found with any of the propanil × 2,4,5‐T treatments. Low rates of propanil, 1.3 and 0.72 kg a.i. ha?1, compared favourably with pre‐emergence treatments of thiobencarb, butachlor, oxyfluorfen and pretilachlor (plus a safener) when weed yields were low. Where water management was poor and Ischaemum rugosum Salisb. was the dominant weed, oxyfluorfen applied pre‐emergence at 0.96 kg a.i. ha?1 produced a higher rice and a lower weed yield than the low rates of propanil. In three of the five experiments, weed growth was insufficient to depress rice yields significantly.  相似文献   

9.
Echinochloa crus‐galli is a serious weed worldwide. Microsatellite markers (simple sequence repeats, SSRs) are important molecular markers that are used widely for studying genetic diversity in plants. However, a limited number of SSRs is available for E. crus‐galli. The restriction site‐associated DNA (RAD) sequencing approach was combined with Illumina DNA sequencing for the rapid and mass detection of SSRs in E. crus‐galli. The RAD tags were generated from the genomic DNA of E. crus‐galli and were sequenced in order to produce 6921.6 Mb of high‐quality sequences with 45.1% guanine–cytosine content. In total, 3081 putative SSRs were detected, of which 82.2% were dinucleotide motif‐repeats. AT was the most frequent motif, accounting for 35.0% of the SSRs. In order to test the validity of the SSRs that were developed here, eight SSRs that were selected from putative SSRs were used to study the genetic diversity and structures of 20 E. crus‐galli populations that had been collected from rice fields in eastern China. Ninety‐seven alleles were amplified from the eight microsatellite loci among the 20 E. crus‐galli populations. These populations showed low genetic diversity and were classified on the basis of their genetic structures into three distinct groups that corresponded to the three regions of population sampling. The SSRs that were identified in this study represent a valuable resource for studying the genetic diversity, population biology and evolution of E. crus‐galli.  相似文献   

10.
The inheritance of sulfonylurea (SU) resistance in Monochoria vaginalis was investigated based on the bensulfuron‐methyl response phenotypes of F1 plants between SU‐resistant (R) and ‐susceptible (S) and segregation analysis in F2 progenies. Differences of SU resistance between SU‐R biotypes and F1 plants at the recommended field dose were also investigated by comparing shoot dry weight. All F1 plants survived the treatment with 25 g a.i. ha?1 bensulfuron‐methyl, one‐third of the recommended field dose, and showed similar responses to SU‐R plants. Conversely, all F1 plants died or showed extreme necrosis at 225 g a.i. ha?1, three times the recommended field dose, as SU‐S plants. F2 plants were classified as either R or S phenotype. Segregation for resistance to bensulfuron‐methyl in F2 families did not differ from the expected 3:1 (R:S) ratio at 25 g a.i. ha?1. At 225 g a.i. ha?1, the F2 families segregated in a 1:3 (R:S) ratio. These results suggest that SU resistance in M. vaginalis is controlled by a single nuclear allele with resistance being dominant at low dose and susceptibility dominant at high dose. Moreover, F1 plants died or were extremely injured after application of bensulfuron‐methyl at the recommended field dose, although SU‐R biotypes grew normally.  相似文献   

11.
Echinochloa species are amongst the most problematic weeds in rice fields of Korea. The steady reliance on the Acetyl‐CoA carboxylase (ACCase) and acetolactate synthase inhibiting herbicides for control of these weeds has led to resistance to these herbicides. The objective of this study was to assess the genetic diversity among populations of ACCase inhibitor‐resistant and ‐susceptible Echinochloa crus‐galli and E. oryzicola in Korea, to better understand their population structure and possible origins of resistance. Seven simple sequence repeat markers were applied to assess the genetic diversity between resistant and susceptible E. crus‐galli and E. oryzicola from 12 populations in Korea. Genetic diversity was slightly higher in the resistant group. The Unweighted Pair Group Method using Arithmetic algorithm (UPGMA) dendrogram generated two distinct clades. One clade consisted of Echinochloa spp. from three populations, i.e. Anmyeondo, Gimje 4 and Gongju, which are resistant and differentiated from the susceptible populations, and the other clade contained the rest of the populations. Structure modelling supported two clades of UPGMA clustering. Based on these data, we can infer that some resistant populations are greatly differentiated, whereas other resistant biotypes are still building up resistance in rice fields in Korea. Resistance traits will be fixed and continue to spread over time without proper control measures.  相似文献   

12.
The resistance mechanism of Leptochloa chinensis Nees to propanil was investigated, based on propanil metabolism, aryl acylamidase activity, and chlorophyll fluorescence at the 8 week growth stage of L. chinensis. The concentration of propanil in the leaf and culm extracts of the resistant (R) and susceptible (S) biotypes, as measured by gas chromatography (GC), was found to increase after propanil treatment. The concentration of propanil in the leaf and culm extracts of the S biotype at 72 h was 1.55 and 0.49 µg mL?1, respectively. However, a lower concentration of propanil was observed in the R biotype, as compared to that in the S biotype. The residue of 3,4‐dichloroaniline, as measured by GC, was detected only in the leaf extracts of the R biotype. In contrast, no residue of 3,4‐dichloroaniline was observed in the S biotype. The level of aryl acylamidase in the leaf tissue extracts of the R biotype was ～140% higher than that in the S biotype. The fluorescence studies showed that propanil inhibited the quantum efficiency of the photosystem II in both the R and S biotypes after 2 h of incubation time. However, when the leaf disks were transferred and incubated in deionized water for 48 h, the quantum efficiency increased in the R biotype but decreased in the S biotype. These results suggest that propanil metabolism, enhanced by aryl acylamidase activity, is the most likely factor contributing towards the mechanism of propanil resistance in L. chinensis plants at the 8 week growth stage.  相似文献   

13.
Barnyardgrass, hexaploid Echinochloa crus‐galli, is considered to arise from the hybridization between tetraploid Echinochloa oryzicola and an unknown diploid species. The genetic relationship between E. crus‐galli and E. oryzicola was examined to investigate the position of E. oryzicola in the evolutionary process of E. crus‐galli, based on the nuclear DNA internal transcribed spacer (ITS) and the chloroplast cpDNA trnT‐L, trnL intron, and trnL‐F regions. New World E. crus‐galli was clearly separated from Eurasian E. crus‐galli and showed a close relationship to the American taxa, Echinochloa crus‐pavonis and Echinochloa walteri, in both the ITS and chloroplast DNA. The nrDNA ITS sequences indicated no differentiation between the Eurasian E. crus‐galli and E. oryzicola, in contrast to their clear divergence in the cpDNA sequence. The present results suggest that E. oryzicola is the male donor of E. crus‐galli.  相似文献   

14.
J Y Li  X K Guo  Q Zhang  C H Liu  Z H Lin  Z M Yu  H Wu  H B He 《Weed Research》2015,55(5):441-448
Screening crop accessions for allelopathic activity is of paramount importance for crop allelopathy research. Previous bioassays often did not use a mixed culture of donor and target plants, did not use soil and were not conducted under natural conditions. In this study, we designed an inhibitory‐circle method in which a rice accession (donor plant) and Echinochloa crus‐galli (target plant) were cultured together in paddy soil under natural conditions. First, we determined that the highest allelopathic activity of allelopathic rice accession PI312777 was at the 5‐leaf stage, and the suitable distance of rice seedlings and E. crus‐galli was 12 cm apart. This method was then validated by a field test. A further 40 rice accessions were evaluated for allelopathic activity to E. crus‐galli using this method. Two rice accessions, PI312777 and Taichung Native 1, had highly allelopathic activity to E. crus‐galli (inhibitory rate > 50%), while another accession, Lemont, had non‐allelopathic activity. These experimental results were in accordance with previous studies using direct field experiments. The inhibitory‐circle method integrated three necessary conditions, that is donor and target plants grown together, with soil as the medium and under natural conditions for reliable results. The ‘inhibitory‐circle method’, which combined donor and target plants, soil medium and field conditions, can give reliable results in one step, compared with laboratory screening methods. Also, the ‘inhibitory‐circle method’ gave results in 30‐35 days, thereby substantially reducing the requirements for time, labour and cost.  相似文献   

15.
Uptake and metabolism of propanil were measured in both susceptible (S) and resistant (R) biotypes of Jungle-rice, Echinochloa colona (L.) link at different growth stages. Results showed that there was no significant difference in uptake between S and R biotypes of E. colona at any given growth stage, but that uptake was significantly reduced at older plant growth stages in all biotypes studied. Metabolism of propanil was more rapid in R biotypes than in S biotypes at all growth stages studied. Specific and total aryl acylamidase activity, responsible for the first stage of propanil metabolism, was higher in R biotypes than in S at all growth stages, but declined to about 50% of the maximum at older growth stages, confirming the importance of this enzyme in conferring resistance to this herbicide. The area of necrosis that developed around a single drop of propanil deposited on the adaxial leaf surface was used to assess the degree of propanil resistance; it was found that resistance increased at older E. colona growth stages in contrast to the rate of propanil metabolism and amidase activity. Treatment of leaves with the amidase inhibitors, carbaryl or piperophos, simultaneously with propanil, caused a decrease in resistance at growth stages where amidase activity was greatest. This treatment was less effective at older growth stages. These results show that, in E. colona, propanil metabolism is important for conferring resistance in younger plants (four-six-leaf stage). It is suggested that restricted uptake confers resistance in older plants.  相似文献   

16.
Echinochloa crus‐galli is an important maize weed with significant variation in herbicide sensitivity. This differential response may reflect differences in selection pressure caused by years of cropping system‐related herbicide usage. The herbicide sensitivity of E. crus‐galli populations from three divergent cropping systems was evaluated in dose–response pot experiments. Populations were collected from sandy fields with (i) a long‐term organic cropping system, (ii) a conventional cropping system with maize in the crop rotation or (iii) a conventional cropping system with long‐term monocropping of maize. Each cropping system was represented by six E. crus‐galli populations. The effectiveness of three foliar‐applied maize herbicides (nicosulfuron, cycloxydim and topramezone) and two soil‐applied maize herbicides (S‐metolachlor and dimethenamid‐P) was tested at three doses and two runs. Foliar‐applied herbicides were applied at the three true leaves stage. Soil‐applied herbicides were applied immediately after sowing. The foliage dry weight per pot was determined 4 weeks after treatment. Plant responses were expressed as biomass reduction. Herbicide sensitivity was consistently lowest for populations from maize monocropping systems. Compared with populations from organic cropping systems, populations from monocropping systems showed 6.9%, 9.8% and 29.3% lower sensitivity to cycloxydim, topramezone and nicosulfuron respectively. Populations from the conventional crop rotation system showed intermediate sensitivity levels, which did not significantly differ from sensitivity levels of populations from the other cropping systems. Sensitivity to dimethenamid‐P and S‐metolachlor was not affected by cropping system. Environmental conditions influenced herbicidal response . This study indicated that integrated weed management may be necessary to preserve herbicide efficacy over the long term.  相似文献   

17.
Echinochloa crus‐galli (L.) Beauv. var. formosensis Ohwi (2n = 6x = 54, AABBCC genomes) and Echinochloa oryzicola (Vasinger) Vasinger (2n = 4x = 36, AABB) are major paddy weeds in East and Southeast Asia. E. oryzicola has been generally considered to be a paternal genome donor of E. crus‐galli s. l., which includes E. crus‐galli var. formosensis based on cpDNA sequences. Thus, molecular characterization using polymerase chain reaction‐restriction fragment length polymorphism analysis of cpDNA has been proposed as a reliable method for discriminating between the two species. In this study, we report that four accessions of E. crus‐galli var. formosensis from Okinawa, Nagasaki, Shizuoka and Tokyo had similar cpDNA sequences to E. oryzicola and had been misidentified as E. oryzicola using molecular methods. In addition, our results demonstrated that these accessions likely inherited their chloroplast genomes from E. oryzicola and not from an anonymous diploid species during polyploidization. Our findings provide new insights into the evolution of E. crus‐galli s. l. and suggest that identification using the cpDNA molecular method alone is not an appropriate approach to differentiate E. crus‐galli var. formosensis and E. oryzicola.  相似文献   

18.
This study was conducted to evaluate the cross‐resistance of acetolactate synthase (ALS) inhibitors with different chemistries, specifically azimsulfuron (sulfonylurea), penoxsulam (triazolopyrimidine sulfonanilide) and bispyribac‐sodium (pyrimidinyl thio benzoate), in Echinochloa oryzicola and Echinochloa crus‐galli that had been collected in South Korea and to investigate their herbicide resistance mechanism. Both Echinochloa spp. showed cross‐resistance to the ALS inhibitors belonging to the above three different chemistries. In a whole plant assay with herbicides alone, the resistant/susceptible ratios for azimsulfuron, penoxsulam and bispyribac‐sodium were 12.6, 28.1 and 1.9 in E. oryzicola and 21.1, 13.7 and 1.8 in E. crus‐galli, respectively. An in vitro ALS enzyme assay with herbicides showed that the I 50‐values of the resistant accessions were approximately two‐to‐three times higher than the susceptible accessions, with no statistical difference, suggesting that the difference in ALS sensitivity cannot explain ALS inhibitor resistance in Echinochloa spp. for azimsulfuron, penoxsulam and bispyribac‐sodium. A whole plant assay with fenitrothion showed that the GR 50‐values significantly decreased in both the resistant E. oryzicola and E. crus‐galli accessions when azimsulfuron, penoxsulam and bispyribac‐sodium were applied with the P450 inhibitor, while no significant decrease was observed in the susceptible accessions when the P450 inhibitor was used. Thus, these results suggest that ALS inhibitor cross‐resistance for azimsulfuron, penoxsulam and bispyribac‐sodium is related to enhanced herbicide metabolism.  相似文献   

19.
Glyphosate is one of the most commonly used broad‐spectrum herbicides over the last 40 years. Due to the widespread adoption of glyphosate‐resistant (GR) crop technology, especially corn, cotton and soybean, several weed species have evolved resistance to this herbicide. Research was conducted to confirm and characterize the magnitude and mechanism of glyphosate resistance in two GR common ragweed ( A mbrosia artemisiifolia L.) biotypes from Mississippi, USA. A glyphosate‐susceptible (GS) biotype was included for comparison. The effective glyphosate dose to reduce the growth of the treated plants by 50% for the GR1, GR2 and GS biotypes was 0.58, 0.46 and 0.11 kg ae ha?1, respectively, indicating that the level of resistance was five and fourfold that of the GS biotype for GR1 and GR2, respectively. Studies using 14 C‐glyphosate have not indicated any difference in its absorption between the biotypes, but the GR1 and GR2 biotypes translocated more 14 C‐glyphosate, compared to the GS biotype. This difference in translocation within resistant biotypes is unique. There was no amino acid substitution at codon 106 that was detected by the 5‐enolpyruvylshikimate‐3‐phosphate synthase gene sequence analysis of the resistant and susceptible biotypes. Therefore, the mechanism of resistance to glyphosate in common ragweed biotypes from Mississippi is not related to a target site mutation or reduced absorption and/or translocation of glyphosate.  相似文献   

20.
Aryl acylamidase (aryl-acylamine amidohydrolase, EC 3.5.1.13) activity has been measured in crude extracts from leaves of propanil-susceptible (S) and propanil-resistant (R) biotypes of the grass weed. Echinochloa colona (L.) Link from Columbia. Both specific and total amidase activity increased with plant age up to 15 days (four-leaf stage), then decreased beyond 20 days to about 50% of the maximum at 36 days in both R and S E. colona biotypes. Specific activity with propanil in the R biotype was about 80% of that obtained for rice (Oryza sativa L.), compared to 25% in the susceptible biotype. The specific activity of the propanil amidase was three-fold higher in the R biotype than in the S. Partially purified amidase extracts from rice and both S and R biotypes of E. colona were compared biochemically. Both rice and E. colona amidases had a pH optimum of 7.5 and native relative molecular masses, estimated by gel filtration, of 179 000 and 181 000, respectively. Out of six substrates tested, three produced appreciable activity (propanil, 4-chloroacetanilide and acetanilide) in both rice and E. colona. Michaelis constants showed that the rice amidase had a higher affinity for propanil (0.36 mM) than had the E. colona enzyme (1.1 mM). Carbamates and organo-phosphorus pesticides were shown to inhibit amidase activity in partially purified rice and E. colona extracts. Additional preliminary data have implicated peroxidase in the next step of propanil metabolism in vitro. These data demonstrate that increased aryl acylamidase activity contributes to resistance to the herbicide propanil in E. colona weeds. Also, a biochemical comparison of purified aryl acylamidases from S and R biotypes of E. colona is presented for the first time.  相似文献   

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