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1.
A soybean cell line tolerant to isoxaben was isolated by callus selection in herbicide-containing medium. The growth of tolerant suspension cells was not affected by 10 μM isoxaben, which prevented the growth of wild-type cultures. The growth of a wheat cell culture was little affected by isoxaben, in accordance to the tolerance of wheat plants to the herbicide. The metabolic fate of labeled isoxaben in the three types of cultures was examined. By comparison with the sensitive, wild-type soybean cell culture, the tolerance of the selected soybean cell culture and that of wheat cell culture cannot be explained by either quantitative or qualitative differences of herbicide metabolism. These results favor the hypothesis that the sensitivity or tolerance of the cell cultures is determined at the level of the cellular target of the herbicide.  相似文献   

2.
The effect of the auxin herbicide quinclorac on cellulose, callose, and (1→3),(1→4)β-glucan deposition in newly produced cell walls of meristematic root tip cells was examined in maize and barnyard grass. Particularly, the developing cell plate of dividing cells was investigated as a site of de novo cellulose biosynthesis. A cellulose-binding domain of a bacterial cellulase and monoclonal antibodies against the hemicellulose constituents were used for specific labelling in fluorescence microscopic examination. Root-treatment of plants with 100 μM quinclorac in maize and 10 μM quinclorac in barnyard grass decreased cell division activity in root tips and root elongation. Quinclorac did not induce the swelling of root tips into a club shape and a glassy appearance of tissue, which are typical symptoms for the action of cellulose biosynthesis inhibitors such as dichlobenil. During 24 h of treatment, no effects of quinclorac on cellulose deposition at the cell plates and parental walls of meristematic root cells were found. In contrast, 10 μM dichlobenil inhibited cellulose deposition in cell plate formation within 4 h of treatment. Concerning the hemicellulose constituents, increased staining for callose in areas of cell plates and parental cell walls was observed 24 h after treatment with 10 μM quinclorac. Concomitantly, (1→3),(1→4)β-glucan deposition in cell walls decreased. The latter may be an indirect effect of quinclorac through a stimulated production of cyanide from ethylene biosynthesis. In contrast with previous reports, no evidence that quinclorac, directly or indirectly inhibits cellulose biosynthesis in roots of susceptible grasses was found.  相似文献   

3.
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   

4.
Benzoylphenylureas (BPUs) were discovered as novel type insecticides about a half century ago; many analogs have been launched as insecticides and acaricides. BPUs are known to inhibit chitin synthesis in insects and other arthropods, but they have no effect against microorganisms such as fungi. We designed new chitin synthesis inhibitors based on the hypothesis that biomolecules that play important roles in cellulose and chitin biosynthesis are similar. In the full automatic modeling system (FAMS), the cellulose synthase was selected as a template three-dimensional structure. Thus, we focused on the structure of cellulose synthase inhibitor, isoxaben, to develop new chemistry. The 1,1-diethylethyl [-C(CH3)(CH2CH3)2] group of isoxaben was changed to a 4-substituted phenyl group bearing Cl, Et, or Ph. These compounds significantly inhibited chitin synthesis in the cultured integument of the rice stem borer Chilo suppressalis. The activity of the 4-ethylphenyl analog was enhanced 30-fold by adding piperonyl butoxide to the culture medium.  相似文献   

5.
Time- and concentration-course studies were conducted to determine the effect of thirteen herbicides on photosynthesis, respiration, RNA synthesis, protein synthesis, and lipid synthesis using isolated single leaf cells. Each herbicide was from a different chemical class. Appropriate 14C-substrates and product purification procedures were used for each process prior to liquid scintillation counting. The most sensitive metabolic site of inhibition was photosynthesis for atrazine, bromacil, dichlobenil, monuron, and paraquat; RNA synthesis for dalapon and dinoseb; protein synthesis for chlorpropham; and lipid synthesis for CDAA, chloramben, 2,4-D, EPTC, and trifluralin. However, with several herbicides, one or more process was almost as sensitive as the one mentioned above. All herbicides inhibited more than one process, and the most sensitive site of inhibition may not be the same process that was inhibited the greatest at the maximum concentration and maximum exposure time used. Therefore, a concept of metabolic sites of action, rather than a primary site of action, appears to be more meaningful for herbicides.  相似文献   

6.
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   

7.
The effects of the herbicides hexazinone [3-cyclohexyl-6-(dimethylamino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] and chlorsulfuron (2-chloro-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)aminocarbonyl]benzenesulfonamide) on the metabolism of enzymatically isolated leaf cells from soybean [Glycine max (L.) Merr., cv. ‘Essex’] were examined. Photosynthesis, protein, ribonucleic acid (RNA), and lipid syntheses were assayed by the incorporation of specific radioactive substrates into the isolated soybean leaf cells. These specific substrates were NaH14CO3, [14C]leucine, [14C]uracil, and [14C]acetate, respectively. Time-course and concentration studies included incubation periods of 30, 60, and 120 min and concentrations of 0.1, 1, 10, and 100 μM of both herbicides. Photosynthesis was the most sensitive and first metabolic process inhibited by hexazinone. RNA and lipid syntheses were also inhibited significantly by hexazinone whereas the effect of this herbicide on protein synthesis was less. The most sensitive and first metabolic process inhibited by chlorsulfuron was lipid synthesis. Photosynthesis, RNA, and protein syntheses were affected significantly only by the highest concentration of this herbicide and longest exposure. Although these two herbicides may exert their herbicidal action by affecting other plant metabolic processes not examined in this study, hexazinone appears to be a strong photosynthetic inhibitor, while the herbicidal action of chlorsulfuron appeared to be related to its effects on lipid synthesis.  相似文献   

8.
The herbicide mefenacet has recently been developed for pre–emergence control of graminaceous and some dicotyledonous weeds in rice. Whereas mefenacet is known to inhibit root growth, its effect on the components of growth, cell division and cell enlargement, have not been determined. The purpose of this study was to evaluate the influence of mefenacet on growth, cell enlargement and cell division in Chlamydomonas (a green alga) and oats. Cell division in Chlamydomonas was completely inhibited and cell enlargement was inhibited by an average of 18% during the first cell cycle period when cells were treated with 6–7 μM mefenacet. The rate of oat root growth in sand culture between 12 and 24 h after initiation of treatment was reduced 90% at 10 μM mefenacet. Cell enlargement of oat coleoptile sections in culture solution was inhibited 25% at 10 μM. Mefenacet inhibited mitotic entry rather than disrupted the mitotic sequence. Cell division in oat roots was inhibited 54% by 10 μM mefenacet. This shows cell division inhibition occurs in G1, S, or G2 of the cell cycle. The action of mefenacet is most like that of the chloroacetamides among the herbicide classes known to inhibit growth.  相似文献   

9.
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   

10.
AC 222,293 was found to exert its mode of action through inhibition of acetolactate synthase, the first enzyme in the biosynthetic pathway of the branched chain amino acids. In vitro AC 222,293 was found to be only a very weak inhibitor of the enzyme, in contrast to the potent inhibition by the free acid, suggesting that action of the herbicide in vivo is dependent on deesterification. Enzyme preparations from susceptible Avena fatua and Alopecurus myosuroides and tolerant wheat (cultivar Fenman) were all equally sensitive with an I50 of approximately 5 · 10−7 M. Inhibition of treated plants is prevented when valine, leucine, and isoleucine are supplied via the nutrient solution. Prominent secondary effects are inhibition of DNA synthesis and cell division and the action of the herbicide is characterised by cessation of leaf growth.  相似文献   

11.
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   

12.
The growth of the root systems of 2-day-old wheat seedlings was more sensitive to the experimental herbicide WL 29226 than was the growth of the shoots. Inhibition of root growth was observed after 12 hr of exposure to the herbicide. The nuclear activity in these root systems, as estimated by RNA and DNA synthesis, was significantly inhibited before this time, ～30% after 4 hr increasing to ～55% after 8 hr. Nuclear activity was inhibited by ～80% after 24 hr and showed little increase in inhibition with any further increase in exposure to the herbicide. Protein synthesis was initially less inhibited, ～6% after 4 hr, rapidly increasing to ～40% after 8 hr. DNA polymerase activity was monitored as an indication of the nucleic acid biosynthetic capacity of herbicide-treated maize and barnyard grass chromatin. In both plants, the herbicide induced an inherent modification of this activity. In maize this was reflected by an inhibition of activity and in barnyard grass by a stimulation. The effect on barnyard grass chromatin is likely to be more complex than in maize because of the presence of a chromatin-bound DNase in the chromatin from control plants. There is no evidence for such an enzyme in the chromatin from either maize or glycerol ether-treated barnyard grass. The apparent stimulation of DNA polymerase activity may in some way be associated with the loss of this nuclease activity. In order to obtain an inhibition of chromatin DNA polymerase, the plants must be pretreated with the herbicide prior to chromatin extraction. The failure of the herbicide to induce an inhibition in vitro on isolated chromatin does not support a direct interaction between the herbicide and chromatin. The results suggest that, following herbicide application to the plant, chromatin integrity has been altered.  相似文献   

13.
The diphenyl ether herbicide oxyfluorfen (2-chloro-4-trifluoromethylphenyl 3-ethoxy-4-nitrophenyl ether) inhibits protoporphyrinogen oxidase (Protox) which catalyzes the oxidation of protoporphyrinogen IX (Protogen) to protoporphyrin IX (Proto IX), the last step of the common pathway to chlorophyll and haeme biosynthesis. We have selected an oxyfluorfen-resistant soybean cell line by stepwise selection methods, and the resistance mechanism has been investigated. No growth inhibition was observed in resistant cells at a concentration of 10(-7) M oxyfluorfen, a concentration at which normal cells did not survive. While the degree of inhibition of total extractable Protox by oxyfluorfen was the same in both cell types, the enzyme activity in the mitochondrial fraction from non-treated resistant cells was about nine-fold higher than that from normal cells. Northern analysis of mitochondrial Protox revealed that the concentration of mitochondrial Protox mRNA was much higher in resistant cells than that in normal cells. There were no differences in the absorption and metabolic breakdown of oxyfluorfen. The growth of resistant cells was also insensitive to oxadiazon [5-tert-butyl-3-(2,4-dichloro-5-isopropoxyphenyl)-1,3,4-oxadiazol-2-(3H)- one], the other chemical class of Protox inhibitor. Therefore, the resistance of the selected soybean cell line to oxyfluorfen is probably mainly due to the overproduction of mitochondrial Protox.  相似文献   

14.
A. WALKER 《Weed Research》1987,27(2):143-152
The movement and persistence of residues of propyzamide, linuron, isoxaben and R-40244 were measured in a sandy loam soil in field experiments prepared in spring and autumn. None of the herbicides moved to depths greater than 12 cm in the soil during the winter period, following application in autumn, and none moved more than 6 cm in the soil, following application in spring. The general order of persistence of total soil residues was isoxaben > linuron = R-40244 > propyzamide. Appropriate constants to describe the moisture and temperature dependence of degradation were derived from laboratory incubation experiments and used with measurements of the strengths of adsorption of the different herbicides by the soil, in a computer model of herbicide movement. The model, in general, gave good predictions of total soil residues, but overestimated herbicide movement, particularly in winter. Measurements of herbicide desorption from the soil at intervals, during a laboratory incubation experiment, demonstrated an apparent increase in the strength of adsorption with time. When appropriate allowance was made for these changes in adsorption in the computer model, improved predictions of the vertical distribution of the herbicide residues were obtained.  相似文献   

15.
Summary. The absorption, translocation and metabolism of the herbicide dichlobenil (2,6-dichlorobenzonitrile) in seedlings of wheat (Triticum vulgare) and rice (Oryza sativa) was investigated using a 14C-labelled preparation. Both plants absorbed the herbicide from water solutions through the roots and translocated it to the shoots. Accumulation was greater in the roots of rice. In wheat, dichlobenil was hydroxylated to form both 3-hydroxy-2,6-dichlorobenzo-nitrile and in smaller quantities, the 4-hydroxy analogue. These conversion products were present mainly as soluble and insoluble conjugates. The insoluble fraction, which apparently consists of phenols conjugated with plant polymers, increased with time. Though the same metabolic processes occurred in rice, the conversion rate was considerably lower. Correspondingly, the dichlobenil concentration was greater in rice than in wheat. No evidence of hydrolysis of dichlobenil was obtained. Migration et métabolisme du dichlobénil dans les plantules de blé et de riz Résumé. L'absorption, la migration et le métabolisme de l'herbicide dichlobenil (2,6-dichlorobenzonitrile) a étéétudiée dans des plantules de blé (Triticum vulgare) et de riz (Oryza sativa) en utilisant une préparation marquée au 14C. Dans les deux espéces, l'herbicide absorbéà partir de solutions aqueuses par les racines fut transporté dans la partie aérienne. L'accumulation fut plus importante dans les racines du riz. Dans le blé, le dichlobenil fut hydroxylé pour donner à la fois du 3-hydroxy-2,6-dich-lorobenzonitrile, et, en plus faibles quantités, le composé analogue 4-hydroxy. Ces produits de conversion furent identifiés principalement sous forme de composés solubles et insolubles. La fraction insoluble, qui consiste apparemment en composés avec des polymeres de la plante, s'accrut avec le temps. Bien que le processus métabolique füt le même dans le riz, le taux de conversion fut considérablement plus faible. Corrélativement, la concentration du dichlobénil fut'plus grande dans le riz que dans le blé. II ne fut pas acquis de preuves de l'hydrolyse du dichlobénil. Transport und Abbau von Dichlobenil in Weizen- und Reiskeimpflanzen Zusammenfassung. Absorption, Translokation und Abbau von 14C-Dichlobenil (2,6-Dichlorbenzonitril) in Keimpflanzen von Weizen (Triticum vulgare) und Reis (Oryza sativa) wurden untersucht. Beide Pflanzen absorbierten das Herbizid aus einer wässrigen Lösung durch die Wurzeln und leiteten es in die Sprosse. Die Akkumulierung war in den Wurzeln von Reis grösser. In Weizen wurde Dichlobenil hydroxyliert, wobei 3-Hydroxy-2,6-dichlorbenzonitril und in geringerer Menge das 4-Hydroxy-Analog entstanden. Diese Konversionssubstanzen waren hauptsachlich als losliche und unlosliche Konjugationsprodukte anwesend. Die unlösliche Fraktion, die offensichtlich aus Konjugationsprodukten mit Pflanzenpolymeren bestand, nahm mit der Zeit zu. Obwohl derselbe Stoffwechselprozess auch im Reis ablief, war doch die Konversions-geschwindigkeit wesentlich geringer. Dementsprechend war die Dichlobenilkonzentration in Reis grösser als in Weizen. Für eine Hydrolyse von Dichlobenil ergaben sich keine Anhaltspunkte.  相似文献   

16.
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   

17.
The greater susceptibility to difenzoquat of Sicco compared with Butler spring wheat could not be attributed to differences in retention of spray solution, development of chlorosis, foliar penetration, and movement of [14C]difenzoquat or cell elongation in the coleoptile straight growth test or excised developing leaf segments. However, following difenzoquat treatment, susceptible Sicco compared with tolerant Butler tillered prolifically and sustained a greater reduction in main shoot length, lamina length, and foliage dry matter. While accumulation of [14C]difenzoquat in the region of the apical meristem was similar in both cultivars, DNA synthesis monitored by [14C]thymidine incorporation in sections containing the apical meristem was inhibited substantially more in Sicco than in Butler. It is proposed that a major contribution to the difference in response between the two cultivars is a differential inhibition of DNA synthesis in the apical meristem.  相似文献   

18.
吡唑解草酯对小麦细胞色素P450的诱导作用及其光谱特征   总被引：2，自引：0，他引：2  
用吡唑解草酯浇灌小麦,试验结果表明,50μmol/L吡唑解草酯处理抗6号小麦,可使其细胞色素P450含量达到最大值108.18 pmol/mg蛋白质,为对照组的1.67倍;100μmol/L吡唑解草酯处理敏18号小麦,可使其细胞色素P450含量达到最大值80.97 pmol/mg蛋白质,为对照组的1.86倍。吡唑解草酯对两个小麦品种的细胞色素P450均有诱导作用,抗6号小麦更容易被诱导,这与两小麦品种的耐药性一致。室温(20±1)℃下扫描不同时间的细胞色素P450-CO结合光谱,结果表明,微粒体粗提液室温(20±1)℃保存200 min后,细胞色素P450完全转变为细胞色素P420。  相似文献   

19.
H. H. HOPPE 《Weed Research》1980,20(6):371-376
Effect of diclofop-methyl on the growth und development of Zea mays L. seedlings Diclofop-mcthyl, a diphenoxypropionic acid herbicide, had no effect on the germination of maize (Zea mays) seed. Prc-ger-minated maize embryos showed inhibited radicle growth when treated with the herbicide, but those of beans were considerably less sensitive. The inhibitory effect of the herbicide on maize radicle growth was reversed when the embryos were transferred to herbicide-free medium within 24 h of treatment. The higher concentrations of diclofop-methyl tested (≥10?6 M) induced necrosis on the second day of treatment, which first appeared in the meristematic and elongation zone of the root tip and then via the rest of the root to the grain. The herbicide increased the fresh and dry weight as well as the dry matter content of the radicle tips of Zea mays. These effects were attributed in an accumulation of cell wall material in the herbicide-treated root lips. In the presence of hydroxyurea, a selective inhibitor of cell division, the effect of diclofop-melhyl on radicle elongation was reduced but did not cease complelely. From these results it can be concluded that diclofop-methyl interferes with the processes that effect both cell division and cell elongation.  相似文献   

20.
The deamination of metribuzin was studied in vitro in peroxisomes isolated from the leaves of soybean cultivars which were either metribuzin tolerant, intermediate, or sensitive. The deamination rate observed with peroxisomes from tolerant leaves was about twice the rate observed with peroxisomes from sensitive leaves. The intermediate group was also intermediate with respect to the in-vitro deamination rate. Tolerant and sensitive intact soybean plants were pulse-labeled with [14C]metribuzin via the roots for 5 h. The extractable radioactivity in roots, stems and leaves was measured and separated into metabolites after the 5 h pulse and after an additional 24 h growth in water. The level of DA (deaminated metribuzin) was always significantly higher in the stems and leaves of tolerant soybean plants (4.8–10.0% of the extracted radioactivity) than in sensitive stems and leaves (1.8–2.9%). Conjugates were rapidly formed in tolerant as well as in sensitive soybean tissues. More conjugates were found in the tolerant cultivars, especially after the 5 + 24 h incubation time. Labeled [14C]DA fed to soybean plants via the roots was conjugated two to four times faster than [14C]metribuzin. Tolerant soybean tissue conjugated [14C] DA two to three times faster than sensitive tissue. The results are interpreted as showing that, in tolerant soybean plants, metribuzin is metabolized via deamination and subsequent conjugation, in addition to the well-known direct conjugation of metribuzin parent compound.  相似文献   

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