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1.
The herbicide isoxaben is selectively phytotoxic to dicotyledonous plants, whereas most monocots are tolerant. We previously selected a soybean cell culture tolerant to isoxaben. Some effects of the herbicide on wild-type soybean cells, tolerant soybean cells, and wheat cells were compared. Cytological observations showed that isoxaben induced some disorganization of sensitive soybean cells, especially at the plasma membrane-cell wall interface. Tolerant soybean cells appeared normal in the presence of isoxaben. The growth of wild-type soybean cells was roughly equally sensitive to isoxaben as to dichlobenil, a cellulose synthesis inhibitor. By comparison, the selected soybean line and a wheat cell culture were less sensitive to isoxaben than to dichlobenil. Glucose incorporation into acid-insoluble cell wall material was more inhibited by isoxaben than by dichlobenil in the wild-type soybean cell culture. In the tolerant soybean cell culture, the incorporation was slightly inhibited by isoxaben, but remained sensitive to dichlobenil. In the wheat cell culture, dichlobenil was also more inhibitory but only at high concentrations. Other compounds, inhibitors of cellulose biosynthesis, of glycosylation of lipids or protein, or of cell division, either had no effect on the synthesis of acid-insoluble cell wall material or exerted apparently unspecific inhibitions. The results are consistent with isoxaben inhibiting the synthesis of a cell wall polysaccharide, which could be cellulose.  相似文献   

2.
The soil dissipation of the herbicide isoxaben was studied in field trials in Belgium in winter cereals treated with green manure, cow manure or pig slurry before sowing. Wheat was sown and the soil sprayed with 125 g isoxaben ha?1 in October. Soil samples were analysed by GLC. Isoxaben dissipated with first-order kinetics over the first 6 months with half-lives of 2.9, 4.0, 4.8 and 6.6 months in unamended plots, and plots treated with green manure, cow manure and pig slurry respectively. The organic fertilizer treatments thus increased the isoxaben soil persistence. After 6 months, the organic fertilizer effect was less pronounced, leading to isoxaben soil concen-trations in all treatments becoming similarly low. Isoxaben at 75 gha?1 applied to winter wheat or barley in the spring gave dissipation half lives of 2.1 and 2.4 months, leading to isoxaben soil residues at the beginning of August of 15–21 p.p.b., similar to levels resulting from the autumn appli-cation. The isoxaben soil residues remaining after harvest would be too low to damage a rotational crop. The rates of isoxaben soil dissipation were greater in the spring and summer seasons than during the winter. The dissipation rates of autumn-applied isoxaben were also studied in spring-sown sugar beet and the effects on a variety of springsown rotational crops were investigated. Dissipation dans le sol de I'herbicide isoxaben en culture de céréales La dissipation dans le sol de I'herbicide isoxaben a étéétudiée dans des essais de plein champ, en Belgique, en culture de céréales d'hiver ayant eu avant le semis un engrais vert, un apport de fumier de vache ou de lisier de pore. Le blé a été semé et le sol traité avec 125 g d'isoxaben ha?1en octobre. Les échantillons ont été analysés par GLC. L'isoxaben s'est dégradé pendant les pre-miers mois avec des demi-vies respectives de 2,9, 4,4,8 et 6,6 mois dans les parcelles sans amende-ments, les parcelles avec engrais vert, fumier et lisier. Les amendements organiques ont augmenté la persistance de l'isoxaben dans le sol. Après 6 mois, l'effet des amendements organiques a été moins prononcé, aboutissant à des concentrations d'isoxaben basses et voisines pour tous les traitements. L'isoxaben a 75 g ha?1 appliquéà du blé d'hiver et de l'orge au prin-temps a donné des demi-vies de 2,1 et 2,4 mois, aboutissant à des résidus d'isoxaben dans le sol début août de 15–21 ppb, comparables aux taux resultant d'une application automnale. Les résidus d'isoxaben dans le sol restant après la moisson seraient trop faibles pour endommager une culture suivante. Le taux de dégradation dans le sol de l'isoxaben a été plus é1evé au prin-temps et en été qu'en hiver. Le taux de dégrada-tion de l'isoxaben appliqué en automne a étéégalement étudié sur des betteraves semées au printemps et les ef fets sur plusieurs cultures dans le cadre de la rotation ont étéétudiés. Rückstandssituation von Isoxaben im Boden nach Applikation in Getreide Die Rückstandssituation des Herbizids Isoxaben im Boden wurde in Freilandstudien in Wintergetreide nach Gründüngung, Ausbringung von Stallmist bzw. Schweinegülle untersucht. Das Herbizid wurde im Oktober im Nachsaatverfahren mit 125 g Isoxaben ha?1 angewandt, und die Bodenproben wurden gaschromatographisch analysiert. Das Herbizid wurde über die ersten 6 Monate nach einer Kinetik 1. Ordnung mit “Halbwertszeiten” von 2,9 Monaten im Ausgangsboden, 4,0 Monaten nach der Gründung und 4,8 bzw. 6,6 Monaten in der Stallmist-bzw. Gülle- Variante abgebaut. Durch die organischen Düngungen wurde also die Persistenz des Herbizids im Boden erhöht. Nach 6 Monaten lieβ die Wirkung der Dünger nach, so daβ vergleichbar niedrige Rückstände gefunden wurden. Bei der Nachauflaufbehandlung von Winterweizen und -gerste im Frühjahr mit 75 g Isoxaben ha?1 lagen die Werte für einen 50% igen Rückgang der Ausgangskonzentration bei 2,1 bzw. 2,4 Monaten, und es ergaben sich Anfang August vergleichbar hohe Werte von 15 bis 21 ppb wie bei den Herbstbehandlungen. Diese Rückstände würden zu keinen Schäden an Nachbaukulturen führen. Die Verlustraten waren prozentual über Winter geringer als im Frühjahr. Sie wurden auch in Zuckerrüben untersucht, desgleichen ihre Wirkung auf verschiedene im Frühjahr angebaute Nachbaukulturen.  相似文献   

3.
Plant cell cultures have been used to study the metabolic degradation of 4-amino-5-methyl-2-(tert-butylaminocarbonyl)-1,2,4-triazolin-3-one. The biochemical basis of selectivity was shown to reside in effective metabolic conjugation. The herbicide was eliminated from cell cultures of beet (which is tolerant to it) by conjugation (N-glycolisation), but this occured to only a limited extent with cell cultures of non-target plants such as soybean.  相似文献   

4.
The herbicide diclofop-methyl caused an early and pronounced inhibition of the incorporation of [14C]acetate into leaf lipids of the sensitive plant species maize (Zea may L.), wild oat (Avena fatua L.), and barnyardgrass (Echinochloa crus-galli L.). With an EC50 value of approximately 10?7M inhibition was already apparent 0.5–4 hr after herbicide application. The fatty acid biosynthesis of tolerant bean (Phaseolus vulgaris L.), sugar beet (Beta vulgaris L.), and soybean (Glycine max L.) was not affected, with one exception [wheat (Triticum aestivum L.) belongs to the more tolerant species]; the inhibition of fatty acid biosynthesis, however, was in the same order of magnitude as in sensitive plants. More detailed studies showed that in wheat a recovery from inhibition of fatty acid biosynthesis occurred. Four days after herbicide application (0.18 kg diclofop-methyl/ha) in wheat normal fatty acid biosynthesis was restored, whereas in sensitive maize a 60% inhibition was maintained over the whole experimental period (8 days). The results support the view that tolerance of wheat to diclofop-methyl is based on its inactivation in leaves, whereas the tolerance of dicotyledonous species may probably lie at the level of the site of action of diclofop-methyl. In experiments with intact leaves, the inhibition of fatty acid biosynthesis resulted in an enhanced flow of [14C]acetate into organic acids and amino acids. This effect, however, was not always reproducible in experiments with leaf pieces or isolated root tips.  相似文献   

5.
Pathways of chlortoluron metabolism were compared in excised leaves of four tolerant species, namely wheat (Triticum aestivum var Clement), Bromus sterilis, Galium aparine and Veronica persica. The herbicide was principally detoxified by hydroxylation of the ring methyl in wheat and by N-dealkylation in Veronica persica. Both pathways were involved in Bromus sterilis and Galium aparine. Kinetic study of the degradation showed that capacity to form non-toxic conjugates could, at least partially, explain the tolerance of these species to chlortoluron. In plants treated with 1-aminobenzotriazole, a cytochrome P-450 enzyme inactivator, N-dealkylation of chlortoluron was little or not affected, but ring methyl hydroxylation was strongly inhibited. This suggests that at least two distinct enzymatic systems could participate in this metabolism. Moreover, cytochrome P-450 enzymes could be involved in the ring methyl hydroxylating reaction.  相似文献   

6.
Possible side-effects of the acetolactate synthase (ALS)-inhibiting herbicide chlorimuron-ethyl on Bradyrhizobium japonicum (Kirchner & Jordan) in pure culture and on inoculated soybean plants growing under controlled conditions were investigated. Growth of B japonicum strain E109 was not affected by this herbicide even when exposed to concentrations 150 times higher than recommended field doses. However, nodulation of soybean plants treated 5 days after emergence with chlorimuron-ethyl at standard application rates was impaired: a 38% decrease in the number of nodules per plant was observed four weeks after treatment. Despite nodule number decrease, no changes in shoot nitrogen content could be detected. Total fresh biomass was diminished by 25% in herbicide-treated plants. Leghemoglobin content in nodules did not vary; nevertheless total nodule protein was diminished by 40% in the herbicide-treated group. ALS activity in different soybean tissues and their relative sensitivity to chlorimuron-ethyl were also investigated. Roots and bacteroids had the greatest specific ALS activities. On a fresh weight basis, the bacteroid fraction displayed the highest ALS activity and was also the most tolerant to in vitro chlorimuron addition: 72% of its activity was retained after including 10 microM chlorimuron-ethyl in the reaction mixture. These results indicate that standard application rates of chlorimuron-ethyl will have limited incidence on B japonicum survival, and effects on nodulation may have little long-term consequences on soybean nitrogen fixation potential. The differences found among soybean tissues not only in intrinsic ALS activity but also in their relative sensitivity to this herbicide suggests that, in leguminous plants living in symbiosis with rhizobia, nodules may contribute to an enhanced tolerance to ALS inhibitors.  相似文献   

7.
Experiments were conducted to examine the up take, translocation and metabolism by S. vulgaris of two distinctly different herbicides: 2,4-D, a phenoxyalkanoic acid with growth regulator activity to which this species exhibits complete tolerance, and chlorsulfuron, a sul-fonylurea to which S. vulgaris is highly sensitive. Despite their structural dissimilarities 2,4-D and chlorsulfuron was readily absorbed by S. vulgaris with 65 and 69%, respectively, of the applied dosage being absorbed within 72 hours after treatment. Approximately 35% of the 2,4-D and 10% of the chlorsulfuron label was translocated out of the treated leaf after 72 hours. Neither herbicide accumulated in the terminal bud. Seventy-two hours after treatment 63% of the recovered 14C remained as unaltered 2,4-D in S. vulgaris, while in tomato, a 2,4-D sensitive species, 65% of the recovered 14C remained as intact herbicide. In S. vulgaris approximately 86% of the radioactivity remained as intact chlorsulfuron 72 hours after treatment compared to 12% in the tolerant wheat. The tolerance of S. vulgaris to 2,4-D could not be accounted for by limited absorption, translocation nor metabolic degradation of the herbicide. The sensitivity of S. vulgaris to chlorsulfuron would appear to be related to the inability of this species to metabolize the herbicide molecule.  相似文献   

8.
Martin FN  Semer CR 《Phytopathology》1997,87(7):685-692
ABSTRACT Sublethal enrichment was used to generate mutants of Pythium sylvaticum tolerant to kanamycin and tetracycline. Kanamycin tolerance was readily generated, and mutants had growth rates similar to wild-type isolates at antibiotic concentrations lethal to wild-type isolates. Based on crosses between wild-type and mutant isolates, two types of inheritance of tolerance were identified. A high level of kanamycin tolerance was inherited in progeny only when the maternal parent was drug tolerant and was correlated with the inheritance of maternal mitochondrial DNA. A lower level of tolerance was observed in some progeny when the paternal parent was tolerant to the antibiotic and, based on the lack of inheritance of paternal mitochondrial DNA, was presumably nuclear-encoded. Selection of mutants tolerant to tetracycline took longer to generate than kanamycin-tolerant mutants. Based on crosses between tolerant and wild-type parents, tolerance to tetracycline was nuclear-encoded. Tolerance to both antibiotics was stable, with cultures retaining tolerance following repeated transfers on nonamended medium and after storage for 7 years.  相似文献   

9.
Investigations were conducted to elucidate the mechanism of selectivity of the auxin herbicide, quinmerac, in cleavers (Galium aparine) and the tolerant crops sugarbeet (Beta vulgaris), oilseed rape (Brassica napus) and wheat (Triticum aestivum). After root treatment with the herbicide, the selectivity has been quantified as approximately 400-fold between oilseed rape and Galium and 1000-fold between sugarbeet or wheat and the weed species. When 1 and 10 μM [14C]quinmerac were applied for 4 h, no significant differences between root absorption and translocation of 14C by Galium and the crop species were found. After 16 h, metabolism of [14C]quinmerac to the biologically inactive hydroxymethyl and dicarboxylic acid derivatives was more rapid in wheat and sugarbeet than in Galium. In oilseed rape, a lower rate of herbicide metabolism was observed. In Galium, accumulations of abscisic acid (ABA), triggered by quinmerac-stimulated ethylene biosynthesis, were found to cause the herbicidal growth inhibition which develops during 24 h of application. Within 1 h of treatment, quinmerac stimulated 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity and ACC concentration specifically in Galium shoot tissue. During the next 4 h, ACC synthase activity was increased up to 50-fold, relative to the control. Within 3 h of exposure to quinmerac, increased ethylene formation followed by higher ABA levels was detected. In sugarbeet, oilseed rape and wheat, quinmerac did not stimulate ACC synthase activity and ACC and ABA levels. It is suggested that (i) the selectivity of quinmerac is primarily based upon the lower sensitivity to the herbicide of the tissue/target in the crop species, (ii) the induction process of the ACC synthase activity in the shoot tissue is the primary target of herbicidal interference. In wheat and sugarbeet, tolerance to quinmerac is additionally increased by a more rapid metabolism. © 1998 SCI.  相似文献   

10.
Photolysis of isoxaben [N-[3-(1-ethyl-1-methylpropyl)isoxazol-5-yl]-2,6-dimethoxybenzamide] in dilute aqueous solutions, adsorbed on silica gel plates, has been investigated under natural and simulated solar light conditions. Eight photoproducts were isolated and identified by spectroscopic methods. Photo-decomposition with sunlight led to the formation of three isomers, dimethoxy-benzonitrile and dimethoxybenzamide as major photoproducts. The rearrangement has been shown to proceed in two photochemical steps by way of an azirine and a non-identified photoproduct as stable intermediates. The azirine rearranges almost quantitatively to an oxazole and rearranges back to the starting isoxaben.  相似文献   

11.
Susceptibility to SMY 1500 (4-amino-6-tert-butyl-3-ethylthio-1.2.4-triazin-5(4H)-one) was studied in durum wheat (Triticum durum Desf.) cultivars in growth-chamber assays. Weight reduction, photosynthesis inhibition and herbicide levels were determined at various times after a 24-h herbicide treatment in two cultivars of durum wheat, one cultivar of spring wheat (Triticum aestivum L). and in the weed Bromus diandrus (Roth). Measurements of weight reduction distinguished between plants tolerant and plants susceptible to SMY 1500. Tolerant cultivars showed a lower herbicide content and photosynthesis inhibition than susceptible plants after the 24-h treatment. Thereafter, herbicide levels and photosystem II inhibition decreased faster in tolerant plants. Comparison with previous work showed that plants tolerated doses of SMY 1500 about four times higher than of its analogue, metribuzin. Herbicide content in leaves just after treatment, and rate of detoxification may explain the selectivity of SMY 1500 in these cereals.  相似文献   

12.
为鉴定新疆不同品种春小麦的耐旱性,筛选耐旱关键性指标并建立可靠的耐旱性数学评价模型,以16个新疆主栽春小麦品种为研究材料,在干旱胁迫和充分灌溉两个条件下,测定全生育期15个相关指标,利用隶属函数、聚类分析和主成分分析等方法对新疆春小麦耐旱性进行综合评价。结果表明：与充分灌溉处理相比,干旱胁迫下灌浆初期叶绿素含量（SPAD1）和灌浆中期冠层温度（CT）显著升高,其他指标不同程度降低。联合方差分析表明,水分和品种对春小麦的各项生理指标、农艺性状和产量性状等单项指标有不同程度的影响。通过主成分分析,以特征值大于1为标准得到6个主成分,可反映原耐旱指标信息的82.292%;通过隶属函数分析,得到不同品种小麦耐旱性综合评价值（D值）。根据综合得分进行聚类分析,将16个品种聚类为4种耐旱类型,其中强耐旱型3个、中耐旱型10个、弱耐旱型2个、旱敏感型1个。通过逐步回归分析法建立SPAD1、成熟期干物质量（DM3）、千粒重（TKW）的回归方程D=-2.258+1.299DM3+1.148SPAD3+0.475TKW,方程决定系数R2=0.962,P=0.0001,表明DM3、SPAD3和TKW可作为耐旱性的主要鉴定指标,利用回归方程可以进行春小麦品种耐旱性的快速鉴定和预测。  相似文献   

13.
Effects of the herbicide EL-107 (N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethoxy-benzamide) on the growth of dicotyledonous plants are described. The herbicide did not inhibit germination but reduced the growth of rape (Brassica napus L.) by half at 0.0057 mg l?1. The most characteristic symptom induced was a swelling of the apical regions, and histological observations of root tips of Polygonum persicaria and rape revealed a progressve disappearance of the meristematic zone, which was replaced by enlarged cells almost devoid of cytoplasm. Growth of cells of Acer pseudoplatanus L. and soybean (Glycine max L.) cultured in suspension was also inhibited by EL-107, which induced a characteristic change in the cell morphology to an enlarged, rounded shape. EL-107 apparently did not block cell division; at a high concentration it produced some inhibition of protein synthesis, but in Acer cells only. In both types of cell cultures it inhibited, to some extent, the incorporation of glucose into cell wall material.  相似文献   

14.
Cinidon-ethyl (BAS 615H) is a new herbicide of isoindoldione structure which selectively controls a wide spectrum of broadleaf weeds in cereals. The uptake, translocation, metabolism and mode of action of cinidon-ethyl were investigated in Galium aparine L, Solanum nigrum L and the tolerant crop species wheat (Triticum aestivum L). When plants at the second-leaf stage were foliarly treated with cinidon-ethyl equivalent to a field rate of 50 g ha−1 for 48 h, the light requirement for phytotoxicity and the symptoms of plant damage in the weed species, including rapid chlorophyll bleaching, desiccation and necrosis of the green tissues, were identical to those of inhibitors of porphyrin synthesis, such as acifluorfen-methyl. The selectivity of cinidon-ethyl between wheat and the weed species has been quantified as approximately 500-fold. Cinidon-ethyl strongly inhibited protoporphyrinogen oxidase (Protox) activity in vitro, with I50 values of approximately 1 nM for the enzyme isolated from the weed species and from wheat. However, subsequent effects of herbicide action, with accumulation of protoporphyrin IX, light-dependent formation of 1-aminocyclopropane-1-carboxylic acid-derived ethylene, ethane evolution and desiccation of the green tissue, were induced by cinidon-ethyl only in the weed species. After foliar application of [14C] cinidon-ethyl, the herbicide, due to its lipophilic nature, was rapidly adsorbed by the epicuticular wax layer of the leaf surface before it penetrated into the leaf tissue more slowly. No significant differences between foliar and root absorption and translocation of the herbicide by S nigrum, G aparine and wheat were found. After foliar or root application of [14C]- cinidon-ethyl, translocation of 14C into untreated plant parts was minimal, as demonstrated by combustion analysis and autoradiography. Metabolism of [14C]cinidon-ethyl via its E-isomer and acid to further metabolites was more rapid in wheat than in S nigrum and G aparine. After 32 h of foliar treatment with 50 g ha−1 of the [14C]-herbicide, approximately 47%, 36%, and 12% of the absorbed radioactivity, respectively, were found as unchanged parent or its biologically low active E-isomer and acid in the leaf tissue of G aparine, S nigrum and wheat. In conclusion, cinidon-ethyl is a Protox-inhibiting, peroxidizing herbicide which is effective through contact action in the green tissue of sensitive weed species. It is suggested that a more rapid metabolism, coupled with moderate leaf absorption, contribute to the tolerance of wheat to cinidon-ethyl. © 1999 Society of Chemical Industry  相似文献   

15.
Imazaquin; a promising herbicide for the control of dodder (Cuscuta spp.) in soybean (Glycine max) Imazaquin, a systemic herbicide, when applied to the leaves of Phaseolus aureus parasitized by Cuscuta lupuliformis was transported and accumulated in the apical part of the stem of the parasite. Similar results were obtained with soybean parasitized by Cuscuta australis. The herbicide was rapidly metabolized by the soyabean plant, but stops the development of dodder by inhibiting cell division. The phloemmobility of imazaquin, its physiological selectivity on soybean, and its efficacy on dodder make this a promising herbicide for the chemical control of dodder in soybean, as was shown by preliminary trials in greenhouse.  相似文献   

16.
Summary. The effect of pre- and post-emergence applications of neburon on the growth of Pueraria phaseoloides and Centrosema pubescens has been tested. Pueraria phaseoloides was adversely affectcd by both applications, seprately and combined, the effect being greater on a sandy soil than on a clay soil. Centrosema pubescens showed greater tolerance, and was little affected by post-emergence treatment but pre-emergence treatment showed some adverse effect.
The check to growth of the legumes could be offset by increased rates of sowing. It appears that neburon might be suitable as a selective herbicide for application in tropical legumes.
Le néburon, herbicide sélectif pour les cultures de légumineuses tropicales  相似文献   

17.
Laboratory studies have shown that the amounts of glutathione (GSH) and cysteine are higher in grass species that are moderately tolerant, such as wheat (Triticum aestivum L., cv. Fredrick), and moderately susceptible, such as barley (Hor deum vitlgare L., cv. Legér) and triticale (cv. OAC Trillium), to fenoxaprop-ethyl (FE) than in species that are very susceptible to the her bicide, such as oat (Avena saliva L., cv. OAC Woodstock), wild oat (Avena fatua L.), yellow foxtail (Setaria glanca (L.) Bcauv.), large crab grass (Digitaria sanguinalis (L.) Scop.) and bar nyard grass (Echinochloa crus-galli (L.) P.B.). The safener, fenchlorazole-ethyl (FCE) was found to increase and decrease, respectively, the amounts of GSH and cysteine in the moderately tolerant and moderately susceptible species but had no effect on the susceptible species. It is sug gested that in the moderately tolerant and moderately susceptible species, especially following FCE treatment, more GSH is available to detoxify the herbicide. Glutathione-S-tranferase activity (GST) for FE was found to be very low in all of the species tested. In vitro experiments at physio-logical pH. demonstrated that FE may conjugate with GSH nonenzymatically. Therefore, it is suggested that nonenzymatic conjugation of fenoxaprop-ethyl with glutathione may be an important mechanism for tolerance of some grasses to this herbicide.  相似文献   

18.
Propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate (ZJ0273), derived from a precursor compound pesticide (a derivative of 2-pyrimidinyloxy-N-aryl benzoate), is a novel herbicide used in the rapeseed field. This paper studied the differential tolerance or susceptibility of four plant species viz. Brassica napus L. (rapeseed), Hordeum vulgare L. (barley), Malachium aquaticum (L.) Fries (water chickweed), and Alopecurus aequalis Sobol. (equal alopecurus), to various concentrations of ZJ0273, based on the rate of inhibition of acetolactate synthase (ALS) activity. Brassica napus was observed as the most tolerant among four species in which ALS activity in vivo was hardly affected by ZJ0273 at 100 mg/L (recommended dose in the rapeseed field). In contrast, H. vulgare was found to be more susceptible which was reflected in the relative decline of ALS activity and lower biomass production even under at a lower rate of 10 mg/L of ZJ0273. The two weed species exhibited moderate susceptibility as compared to H. vulgare. The present study confirmed that ZJ0273 at 100 mg/L is the optimal dose of herbicide for rapeseed field. Seedling stage was critical in determining the tolerance of crops and susceptibility of weeds which indicated that over seven leaf stage was much safer for rapeseed whereas the two leaf stage juvenile water chickweed was more susceptible to the same rate of ZJ0273. Spatial and temporal variations in ALS activity as affected by 100 mg/L ZJ0273 in water chickweed, rapeseed and barley also suggested that the synchronized sampling based on the tissue position and seedling stage was necessary to examine precisely, the special difference in tolerance or susceptibility to ALS-inhibiting herbicide. The uppermost younger leaf seemed to be the most appropriate sample for evaluation. Furthermore, the variant tendency of ALS activity from different parts of plants between monocotyledons and dicotyledons to ZJ0273 treatments showed differential response which revealed some possible mechanism related to the altered absorption and translocation of the herbicide.  相似文献   

19.
施肥对麦田杂草发生、生长及危害的影响   总被引：5，自引：0，他引：5  
应用微区试验研究了在种植小麦的情况下,不同施肥水平对杂草及其防除效果的影响。结果表明,在缺磷土壤上单施氮肥,杂草发生和生长受到抑制;增施磷肥,氮肥效应得到充分发挥,杂草发生和生长迅猛提高。杂草根系发达,对钾肥不敏感。有机肥养分完全,显著促进杂草发生和生长。在不施肥(对照)及适合杂草和小麦生长的平衡施肥处理区(NP和NPK),麦田杂草的危害(小麦减产百分率)最为严重。杂草危害程度和施除草剂的增产效果均与小麦长势呈极显著负相关(相关系数分别是-0.5121、-0.5418,n=27)。肥料对甲磺隆钠盐杂草防效的影响与施药时间有关。在小麦苗前至苗后早期施药,防效高,且不受施肥影响;施药过迟,杂草长大,防效下降。研究结果还表明,杂草发生和生长在受施肥影响的同时,也受小麦长势和长相的影响。  相似文献   

20.
Conyza bonariensis is a major weed infesting zero‐tilled cropping systems in subtropical Australia, particularly in wheat and winter fallows. Uncontrolled C. bonariensis survives to become a problem weed in the following crops or fallows. As no herbicide has been registered for C. bonariensis in wheat, the effectiveness of 11 herbicides, currently registered for other broad‐leaved weeds in wheat, was evaluated in two pot and two field experiments. As previous research showed that the age of C. bonariensis, and to a lesser extent, the soil moisture at spraying affected herbicide efficacy, these factors also were investigated. The efficacy of the majority of herbicide treatments was reduced when large rosettes (5–15 cm diameter) were treated, compared with small rosettes (<5 cm diameter). However, for the majority of herbicide treatments, the soil moisture did not affect the herbicide efficacy in the pot experiments. In the field, a delay in herbicide treatment of 2 weeks reduced the herbicide efficacy consistently across herbicide treatments, which was related to weed age but not to soil moisture differences. Across all the experiments, four herbicides controlled C. bonariensis in wheat consistently (83–100%): 2,4‐D; aminopyralid + fluroxypyr; picloram + MCPA + metsulfuron; and picloram + high rates of 2,4‐D. Thus, this problem weed can be effectively and consistently controlled in wheat, particularly when small rosettes are treated, and therefore C. bonariensis will have a less adverse impact on the following fallow or crop.  相似文献   

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