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1.
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   

2.
Isoxaflutole is a new pre-emergence corn herbicide which controls both grass and broadleaf weeds. Experiments were performed in the laboratory to study the sorption of isoxaflutole in five different soils (Moorhead, MN; East Monroe, CO; Ellendale, MN; South Deerfield, MA; and Chelsea, MI) using the batch equilibration technique. Total initial isoxaflutole solution concentrations for each soil were 0.05, 0.15, 0.3. 0.8, 1.5, 2.0 and 4.0 mg litre−1. Analysis of [ring-14C] isoxaflutole was performed using liquid scintillation counting, and sorption data were fitted with the Freundlich model. Isotherms of isoxaflutole in all the soils were non-linear as depicted by the exponent (n < 1.0), indicating differential distribution of sorption site energies in various soils. Since the isotherms were non-linear the data fit Freundlich's isotherm well, as was indicated by high values of the regression coefficient (r2). The Freundlich sorption coefficient ranged from 0.555 to 50.0 (litre nmg lnkg−1). Multiple regression of the sorption constant, KF against selected soil properties indicated that organic matter content was the best single predictor of isoxaflutole sorption (r2 = 0.999) followed by soil pH (r2 = 0.954). Clay content of the soils did not have a high correlation with KF values (r2 = 0.453), while the sorption of isoxaflutole was not influenced by the Ca2+ concentration in the soil solution. Isoxaflutole sorption increased with an increase in organic matter content of soils. Sorption of isoxaflutole decreased as the soil pH increased from 4.5 to 8.5, which was depicted by the reduction of KF values. Sorption of isoxaflutole to the soils varied with differences in binding energies. At a particular net energy value (E*), the corresponding site energy distribution [F(E*)] values followed the order, Chelsea, MI > Moorhead, MN > East Monroe, CO > South Deerfield, MA > Ellendale, MN. The negative magnitude of Gibbs free energy of sorption (ΔG x) indicates the spontaneity of the given sorption process in the soils from Moorhead, MN; East Monroe, CO and Chelsea, MI. © 1999 Society of Chemical Industry  相似文献   

3.
The present study was conducted to assess the plant growth promoting activities of Mesorhizobium sp. in the presence of technical grade herbicides and its ameliorating effects on herbicide toxicity to chickpea grown in herbicide treated soils. The quizalafop-p-ethyl and clodinafop-tolerant Mesorhizobium isolate MRC4 recovered from the nodules of chickpea plants significantly produced IAA, siderophores, hydrogen cyanide and ammonia in medium amended with or without technical grade quizalafop-p-ethyl and clodinafop. Quizalafop-p-ethyl at 40, 80 and 120 μg kg−1 soil and clodinafop at 400, 800 and 1200 μg kg−1 soil in general, decreased the growth attributes of chickpea plants inoculated with Mesorhizobium MRC4 and un-inoculated chickpeas. The three concentrations of quizalafop-p-ethyl were comparatively more toxic and substantially decreased biomass, nodulation and leghaemoglobin content, nutrient uptake, seed yield and grain protein over the un-inoculated chickpea. Interestingly, Mesorhizobium isolate MRC4 with any concentration of the two herbicides significantly increased the measured parameters when compared to the plants grown in soils treated solely (without inoculant) with similar concentration of each herbicide. Conclusively, Mesorhizobium isolate MRC4 could be exploited as bio-inoculant for facilitating chickpea growth under herbicide stress.  相似文献   

4.
为明确异噁唑草酮对玉米根际土壤微生物碳、氮及酶活性的影响, 采用田间试验的方法, 以1倍、5倍和10倍田间推荐剂量为供试除草剂剂量, 测定了异噁唑草酮土壤封闭处理对玉米根际土壤微生物量碳、氮及土壤脲酶、过氧化氢酶、蔗糖酶、脱氢酶和中性磷酸酶活性的影响。结果表明:推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮含量无显著影响, 5倍和10倍推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮含量具有抑制作用。推荐剂量的异噁唑草酮对玉米根际土壤脲酶、过氧化氢酶和蔗糖酶影响较小, 5倍和10倍推荐剂量的异噁唑草酮对其具有明显的抑制作用。异噁唑草酮对土壤脱氢酶活性具有抑制作用, 且施用剂量越高, 抑制作用越强。异噁唑草酮对土壤中性磷酸酶活性的影响表现为前期促进, 后期抑制, 且施用剂量越大, 促进或抑制作用越强。研究表明:推荐剂量的异噁唑草酮对玉米根际土壤微生物量碳、氮及土壤脲酶、过氧化氢酶和蔗糖酶活性的影响较小, 但对土壤脱氢酶、中性磷酸酶活性有影响。  相似文献   

5.
Isoxaflutole is a relatively new herbicide used for weed control in maize. The objective of this research was to increase the understanding of the behaviour and environmental fate of isoxaflutole and its diketonitrile (DKN) degradate in soil, including determination of the strength of sorption to soil and whether sorption is affected by ageing. In sandy loam (SL) and silty clay (SiCl) soils, 14C‐isoxaflutole was found to dissipate rapidly after application to soil; recovery ranged from ~42% to 68% at week 0, and recovery had decreased to <10% at week 12. Decreases in 14C isoxaflutole residues over time in SL and SiCl soils are consistent with hydrolysis of isoxaflutole and formation of bound DKN residues in the soil. DKN recovery from freshly treated SiCl and SL soils was 41% to 52%. After a 12‐week incubation in SL soil at pH 7.1 and 8.0, recoveries were similar, ~40%. However, at week 12 in SL soil pH 5.7, DKN recovery decreased to ~28%. DKN recovery in SiCl soil at week 12 was <10%. Increases in sorption of DKN in SL at pH 5.7 and SiCl soil over time indicate that the DKN degradate is tightly bound to the soil and sorption is affected by soil pH and soil type. Sorption of 14C‐DKN in the SiCl soil more than doubled with ageing compared with the lower Kd sorption coefficient values of the SL soils. In the SiCl soil at time 0, the Kd was 0.6; at 1 week, Kd increased to 2; and at the end of the 12‐week incubation period, Kd was 4.5. This strong binding of DKN to the soil may be due to chelate formation in the interlayer of the clay.  相似文献   

6.

Lack of control options for cool-season broadleaf weeds is a major deterrent to autumn-sown chickpea. Weed control and chickpea tolerance to PRE (pre-emergence) and POST (post-emergence) application of isoxaflutole and oxyflurofen, PRE metribuzin, POST pyridate, and flumetsulam were investigated at three locations, including Kermanshah, Kurdistan, and Hamedan provinces during 2017–2018. Untreated and weed-free checks were added for comparison. Pyridate and PRE oxyflurofen 125?g ai ha?1 caused the minor visual crop injury according to EWRS score (1–1.8), while the highest crop injury occurred with metribuzin (EWRS score 3.5–8.5) in whole locations. The most effective herbicides for weed reduction were pyridate (70–75%), PRE oxyfluorfen (69–76%), and POST oxyfluorfen (65–73%) at Kermanshah, PRE oxyfluorfen at 125 and 175?g ai ha?1 (70–78%), POST oxyfluorfen (70–76%) and pyridate (70–78%) at Kurdistan, PRE oxyfluorfen at 125 and 175?g ai ha?1 (88–96%), metribuzin (91–100%) and Pyridate (80–97%) at Hamedan. Pyridate and PRE oxyfluorfen at 125?g ai ha?1 resulted in the highest chickpea grain yield at the three locations. In general, PRE oxyfluorfen (125?g ai ha?1) was similar to pyridate in terms of efficacy in weed control and grain yield enhancement.

  相似文献   

7.
为了明确2种增效剂对除草剂的减量效应,为除草剂科学减施及增效剂安全使用提供数据基础,2019年在西北荒漠绿洲生态区春玉米田,以38.5%硝·精·莠去津CS和26.7%噻隆·异噁酮SC作为茎叶处理剂,测定了激健和辉丰2种增效剂在不同施药剂量下的除草效果.结果 表明:在38.5%硝·精·莠去津CS 2310 mL/hm和2...  相似文献   

8.
In this study, the results of two-year investigations on herbicide resistance in silky bent grass (Apera spica-venti) populations are presented. Two populations of A. spica-venti were sown in a winter wheat field at the Ihinger Hof Research Station near Stuttgart in Germany in October 2008. Whole-plant bioassays conducted with both populations in the greenhouse before the field trial was set up revealed that population A was strongly resistant to acetolactate synthase (ALS)-inhibitors, whereas population B was sensitive to this group of herbicides. Each block was treated with isoproturon, fenoxaprop-P-ethyl, sulfosulfuron and meso-iodosulfuron at the recommended field dose. One treatment remained unsprayed. It was found that the average number of silky bent grass panicles was significantly higher in the second year (2010) with 343 panicles m? 2 in the untreated control compared to 44 panicles m? 2 in the first year (2009). Efficacy of both ALS-inhibitors was significantly reduced in the resistant population compared to the sensitive population. Grass-weed plants surviving treatments with ALS-inhibitors produced the same number of seeds as the untreated plants. It was found that germination rate of seeds from the resistant population was more than threefold higher than from the sensitive population. Grain yield was equal in all treatments and populations in 2009. In 2010, applications of isoproturon and fenoxaprop-P-ethyl resulted in higher grain yields, with a mean of 4.6 t ha? 1 compared to an average of 3.9 t ha? 1 in the plots treated with sulfosulfuron and meso-iodosulfuron and 4.3 t ha? 1 in the untreated plots. However, these differences were not statistically significant. The sensitive population of the second generation (2009/2010) was approximately 20% more tolerant to ALS-inhibitors than the sensitive population of the first generation (2008/2009) which indicates introgression of herbicide resistance traits already after one year. These results clearly show that herbicide resistance to ALS-inhibitors in silky bent grass is likely to spread rapidly causing significant economic losses. Therefore, management strategies need to be developed and tested to prevent and overcome herbicide resistance in European cereal production systems.  相似文献   

9.
SEIDEN  KAPPEL  STREIBIG 《Weed Research》1998,38(3):221-228
A herbicide bioassay based on tissue cultures of Brassica napus L. was evaluated with selected sulfonylurea herbicides. Data were analysed by fitting the results to a log-logistic dose–response model. Within an experiment, the non-linear regression models were fitted simultaneously to the individual dose–response curves. The results obtained showed good response to even low concentrations of herbicide, with detection limits in the range 0.008–0.69 nmol L?1 for chlorsulfuron and 0.02–0.13 nmol L?1 for metsulfuron. The reproducibility of the assays, on the basis of coefficient of variation of the ED50 values, was found to be 44% for chlorsulfuron and 48% for metsulfuron measurements. Assay of herbicide dissolved in aqueous soil extract showed significant interference from this matrix on the response, requiring a five times dilution of the extract to overcome this matrix effect.  相似文献   

10.
A Penicillium chrysogenum strain was isolated for its ability to grow in minimal medium containing the herbicide glyphosate as the only nitrogen source. The presence of concentrations up to 25 mM progressively stimulated the fungal growth rate, which was negligible in media lacking reduced nitrogen. However, glyphosate utilization never exceeded 1 mmol g-1 mycelial dry mass, and below a threshold concentration both herbicide uptake and fungal growth were subject to a lag phase, suggesting that the herbicide may enter the cell by either simple passive diffusion or inducible carriers. Amino acids, possible products of glyphosate breakdown, as well as ammonia, were found to replace the herbicide in restoring mycelial growth. Cells were devoid of detectable nitrate reductase activity, thus the isolate seems to be impaired in its ability to convert nitrate to ammonium. In vitro activity of 5-enol-pyruvyl-shikimate-3-phosphate synthase, the target site of glyphosate action, was highly sensitive to the herbicide. Fungal growth rate was considerably lower when the herbicide was also the only phosphorus source, whereas glyphosate utilization was substantially unaffected, suggesting an unusual route for its degradation. Herbicide metabolism was strongly reduced when other sources of organic nitrogen were made available.  相似文献   

11.
The effects of seven fungicides, seven herbicides and six insecticides on nitrogen fixation and nodulation by the dry bean (Phaseolus vulgaris L. cv “Bonus”) were investigated. All pesticides examined were found innocuous to nitrogen fixation (acetylene reduction) except bentazone, a post-emergence herbicide. Bentazone at 3 × label rate (6.7 kg ha?1) consistently depressed nitrogen fixation rates within 48 h after application. However, rates recovered and were comparable to those of control plants after 6 days. No effects were observed on nodulation from any of the pesticides (3 × or label rate) applied.  相似文献   

12.
Greenhouse studies were conducted to evaluate the sensitivity of three commercial cultivars, eight experimental cultivars and common bermudagrass to clethodim, glufosinate and glyphosate. Each herbicide was applied at eight doses. Data were regressed on herbicide dose using a log-logistic curve (R2 = 0.56-0.95 for clethodim, R2 = 0.60-0.94 for glufosinate, and R2 = 0.70-0.96 for glyphosate). The herbicide rate that elicited a 50% plant response (I50) in the bermudagrass cultivars ranged from 0.04 to 0.19 kg ha(-1) clethodim, 0.19 to 1.33 kg ha(-1) glufosinate and 0.34 to 1.14 kg ha(-1) glyphosate. Relative to other cultivars, common bermudagrass was intermediate in its response to clethodim and among the most tolerant cultivars to glufosinate and glyphosate. TifSport was relatively tolerant to clethodim and glufosinate compared with other cultivars, but relatively sensitive to glyphosate. One cultivar, 94-437, was consistently among the most sensitive cultivars to each of the herbicides. While there were differential herbicide tolerances among the tested bermudagrass cultivars, there did not appear to be any naturally occurring herbicide resistance that could be commercially utilized. However, research indicated that breeding efforts should target herbicide resistance that is at least four times the registered use rate. Also, TifSport and Tifway have been identified as suitable representatives of triploid hybrid bermudagrass cultivars to be used to evaluate the success of turfgrass renovation programs.  相似文献   

13.
R. A. CHRIST 《Weed Research》1985,25(3):193-200
The elongation rates of single attached leaves of rice (Oryza saliva L.) were recorded. The effect of pretilachlor on the elongation rates and the safening effect of CGA 123407 [4, 6-dichloro-2-phenyl-pyrimidine] were evaluated. Both chemicals were applied to the roots in a nutrient solution. Pretilachlor reduced leaf elongation in concentrations as low as 300 μg?1 (9–6 × 10?7 M) but. for combination trials with the safener, 3 mg 1?1 (9–6 × 10?6 M) was used. in combination with pretilachlor the safener prevented damage in very low concentrations. The ratio of pretilachlor to safener, 30:1, was sufficient when both chemicals were given to roots in nutrient solution, although for field work the ratio of 3:1 is recommended. The safener alone did not influence the elongation rate of rice leaves in the concentrations used. When pretilachlor was given to the roots and CGA 123407 to the shoot, some delay in the herbicidal action was recorded but even with high concentrations of the safener no continuous safening effect was achieved. CGA 123407 was also effective when given previous to the herbicide. This proved true even with a 2-day interval between safener uptake and application of the herbicide. When pretilachlor was given first, the safener effected recovery to various degrees when given 1–4 days after the herbicide application. When pretilachlor was given for a limited period of time only (1–3 days) and was subsequently removed from the nutrient solution, recovery of the plant occurred. It is speculated that the safener either helps this recovery or else competitively prevents the herbicide from occupying the sites of action or from keeping them occupied for a long period of time.  相似文献   

14.
R. F. NORRIS 《Weed Research》1991,31(6):317-331
Sugarbeet and weeds were treated with phenmedipham plus desmedipham either as single applications or as split applications in which 50% of the equivalent single application rate was applied at each application. Split application did not alter the phytotoxicity to the crop when environmental conditions did not predispose the Sugarbeet to injury by the herbicide. Split applications at 1-1 or 1-4 kg ha?1 spaced from 0-5 to c. 5 days apart caused more injury to the crop than the respective single applications when environmental conditions were such that injury to the crop resulted from the single applications. Injury to Sugarbeet following application of 0-72 kg ha?1 of phenmedipham plus desmedipham was always low, regardless of the type of application. Susceptible weeds were controlled by single applications of 1 1-1 ?4 kg ha?1, but 0-72 kg ha?1 did not reliably provide adequate control. Split applications c. 3-8 days apart gave improved control. Control achieved by 0-72 kg ha?1 of the herbicide applied as split treatments equalled or exceeded that produced by single applications of 1-4 kg ha?1. Improvement in the control of tolerant weed species by split applications of phenmedipham plus desmedipham was species dependent. Use of low-rate split applications of phenmedipham plus desmedipham thus resulted in reduced injury to the Sugarbeet, and the introduction of less herbicide into the ecosystem, while maintaining or improving the control of susceptible weeds.  相似文献   

15.
Isoxaflutole, [4-(2-methanesulfonyl-4-trifluoromethylbenzoyl)-5-cyclopropyl isoxazole] is a relatively new pre-emergence herbicide which undergoes rapid conversion to a diketonitrile metabolite in soil. The half-life of isoxaflutole is very short but the half-life of diketonitrile is much longer and hence, diketonitrile remains for a extended period of time in soil. Sorption-desorption studies were conducted with five soils varying in physical and chemical properties. The batch equilibration technique was used for the sorption experiments, while completely mixed batch reactor systems with the decant and refill method was used for the desorption experiments. Four subsequent desorptions were examined after the sorption process in each soil with an equilibration period of seven days. An apparent sorption-desorption hysteresis was observed in all five soils. Organic matter content and the clay content of the soils were the two determining factors for hysteresis. In soils with high organic matter content, the sorption-desorption hysteresis was mainly governed by organic matter content, but in soils with low organic matter clay content played an important role. With the exception of the Chelsea soil, which had a very high organic matter content (57.4%), all other soils exhibited a high correlation between the clay content and hysteresis index (HI) values calculated at 0.75 ( r 2 = 0.960), 25 ( r 2 = 0.934) and 150 mg L−1 ( r 2 = 0.928). In conclusion, the potential for leaching through soil and crop injury due to isoxaflutole and its metabolite would decrease as soil organic matter and clay content increases.  相似文献   

16.
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   

17.
In vitro assay procedures for measuring the activity of cysteine biosynthesis from serine (CBS), which is a coupled reaction catalyzed by serine acetyltransferase and cysteine synthase, were developed using crude extracts from sorghum shoots. Cysteine biosynthesis from serine activity was dependent on acetyl‐CoA concentrations (up to 1.5 mmol L?1), serine (at least up to 20 mmol L?1) and sulfide (up to 0.25 mmol L?1), respectively, and was proportional to the protein concentration in the reaction mixture below 0.4 mg mL?1. The reaction rate was 6.6 nmol min?1 per mg of protein during the first 5 min, but increased to 45.6 nmol min?1 per mg of protein between 30 and 45 min after reaction initiation. Sorghum had the highest CBS total activity (222.4 nmol min?1 per g of fresh weight), and large crabgrass had the lowest CBS total activity (4.7 nmol min?1 per g of fresh weight) when CBS activity in shoots was extracted from sorghum, corn, johnsongrass, barnyardgrass, goosegrass, green foxtail and large crabgrass. Similar results were obtained for CBS specific activity (nmol min?1 per mg of protein). There was no correlation between total CBS activity and susceptibility to metolachlor; however, when corn was excluded, a correlation of R2 = 0.690 was found. Flurazole seed treatment (1.25 g per kg of seed) conferred metolachlor resistance by sorghum, and enhanced total CBS activity and non‐protein thiol content by 27 and 61%, respectively. The increase in thiol content presumably contributed to metolachlor tolerance in sorghum. From these results, the difference in CBS activity partially contributes to the selectivity to metolachlor among certain grass species, and to the safening action of flurazole by increasing thiol content.  相似文献   

18.
The objective of this study was to investigate the effects of commercial formulation of herbicide 2,4-D on metabolic parameters, acetylcholinesterase (AChE) activity and liver histological evaluation of silver catfish (Rhamdia quelen) exposed for 96 h. AChE activity increased in brain (600 and 700 mg L−1) and decreased in all concentrations tested in muscle tissue. Hepatic glycogen was reduced after 2,4-D exposure ranging from 47.67% (400 mg L−1) until 59.3% (700 mg L−1). Hepatic tissue showed lactate reduction at all 2,4-D concentrations tested and glucose was reduced only at 700 mg L−1. In the highest concentration tested hepatic glycogen and glucose reduced instead plasma glucose levels increased. White muscle tissue showed glycogen reduction in fingerlings exposed to all herbicide concentrations and glucose reduction at 700 mg L−1. Muscle lactate levels increase at all 2,4-D concentrations tested. Vacuolation of hepatocytes and changes in its arrangement cords were observed by histologic analysis in group treated with 700 mg/L of 2,4-D. These results suggest that silver catfish exposed to concentrations of 2,4-D near of CL50 showed metabolic and histological response to compensate some stress caused by herbicide exposure. Taken together parameters measured can be used as biomarkers to monitor herbicide contaminated water.  相似文献   

19.
The triallate tolerance of wheat (Triticum aestivum L.) cultivars Marius and Mexicali was determined under growth-chamber conditions. Mexicali was found to tolerate triallate at levels about fourfold higher than Marius. The susceptible wheat cultivar was protected against triallate by seed treatment with MON 5501. The herbicide concentration in the aerial part of the plants was determined by gas chromatography. Triallate levels were similar in both cultivars treated with 0.5 mg 1?1 of triallate. The safener did not affect the triallate content per plant in the susceptible wheat cultivar treated with 1 mg 1?1 of herbicide. Augmentation de la tolerance du blé au triallate avec le phytoprotecteur MON 5501 La tolerance au triallate des cultivars de ble Marius et Mexicali a été déterminée en chambre climatique. Mexicali s'est avéré 4 fois plus tolérant que Marius. Le cultivar de blé sensible a été protege du triallate par un traitement des grains avec MON 5501. La concentration en herbicide dans la partie aérienne des plantes a été determined par chromatographie gazeuse. Les taux de triallate ont été equivalents chez les 2 cultivars traites avec 0,5 mg l?1 de triallate. Le phytoprotecteur n'a pas affecté lateneur en triallate par plante chez le cultivar sensible traite avec 1 mg 1?1 d'herbicide. Verbesserung der Toleranz von Weizen gegenuber Triallat mil dem Antidot MON 5501 Die Triallat-Toleranz der Weizensorten ‘Marius’ und ‘Mexicali’ wurde im Phytotron bestimmt. ‘Mexicali’ war etwa 4mal toleranter als ‘Marius’. Die empfindliche Weizensorte wurde durch Beizung mit MON 5501 gegen Triallat geschützt. Die Herbizidkonzentration in den oberirdischen Pflanzenteilen wurde gaschromatographisch bestimmt Der Wirkstoff-Gehalt war in beiden mit 0,5 mg 1?1 Triallat behandelten Sorten ahnlich hoch. Das Antidot hatte keinen Einfluβ auf den Triallat-Gehalt der empfindlichen Weizensorte, die mit 1 mg 1?1 behandelt worden war.  相似文献   

20.
An airflow system has been used to expose tomato plants to a range of concentrations of vapour of the herbicide 2,4-D butyl, from 5 to 50 ng l?1. Experiments carried out at an air temperature of 20°C indicate that only short periods (less than 2.5 h) are required to produce symptoms of phytotoxicity at concentrations less than 5 ng l?1, or approximately 2.5% of the saturated vapour pressure of the herbicide. A 5-h period of exposure to approximately 5 ng l?1 reduced the dry weight and dry matter content of the tomato plants after 7 weeks by 18% and 9%, respectively, compared with the control. Phytotoxicity symptoms were shown by the plants in proportion to the vapour concentration during the period of exposure to herbicide. Rates of photosynthesis of treated plants had begun to decline within an hour of the commencement of exposure, slightly after leaf movement was first observed.  相似文献   

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