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1.
A procedure was developed to obtain non-embryogenic callus and regenerated lines from root segments of Zea mays grown in aseptic conditions. The activity of glutathione-S-transferases (GSTs), for non-embryogenic callus, was determined toward 1-chloro-2,4-dinitrobenzene (CDNB) and it was compared with that obtained for corn seedlings grown without hormones. For the callus masses, increases of specific activity toward CDNB and the kinetic parameter Vmax were observed with respect to corn seedlings. The procedure permitted the regenerating of tissues from callus explants, therefore the GST(CDNB) activity and the effect of the safener benoxacor on its expression were investigated for the regenerated tissues grown in agarized substrate and in liquid medium. These explants showed a constitutive GST(CDNB) activity higher than corn seedlings and this activity was increased, for both tissues, in response to the presence of the safener benoxacor in the growing medium. The GST activity for the above tissues was also assayed toward benoxacor and terbuthylazine, metolachlor and fluorodifen herbicides. Measurable GST activity was found toward some of the above chemicals and it was found to be significantly enhanced in response to benoxacor treatment. 相似文献
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进行了有效成分为异丙甲草胺的96%金都尔乳油、90%禾耐斯乳油（乙草胺）和50%丁草胺乳油的防除花生田杂草的对比试验,结果表明,96%金都尔乳油防除花生田杂草以1 275、900 ml/hm^2防除效果最好,明显高于其他处理,对花生生长无不良影响,安全系数高,可以作为丁草胺、乙草胺的替代除草剂在田间推广应用。 相似文献
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Effects of repeated metolachlor applications on its persistence in field soil and degradation kinetics in mixed microbial cultures 总被引：1，自引：0，他引：1
The persistence of metolachlor, a soil-applied herbicide, was studied under field conditions involving repeated herbicide
applications. The test field received four applications of metolachlor over an 8-month period, which included two cropping
seasons. There was a trend for more rapid rates of degradation with increasing numbers of previous treatments, with fifty
percent dissipation time (DT50) of metolachlor declining from 18 days in the first spray to 2.5 days in the fourth spray. An effort was made to isolate
the microbial population which had become acclimated to the herbicide from this field soil. A fungal community isolated from
this soil showed the capacity to degrade up to 99.6% of the metolachlor within a span of 20 days. The bacterial community
isolated could also degrade up to 81.5% of the metolachlor. Hence, this study clearly indicated that repeated applications
of metolachlor to soil resulted in the generation of an adapted microbial population with an enhanced ability to degrade the
applied herbicide.
Received: 13 November 1998 相似文献
4.
乙草胺和异丙甲草胺在土壤中吸附的研究 总被引：29，自引：1，他引：28
本文研究比较了乙草胺和异丙甲草胺在６种土壤中的吸附,采用Ｆｒｅｕｎｄｌｉｃｈ方程对其吸附等温线进行描述,对Ｆｒｅｕｎｄｌｉｃｈ方程吸附常数Ｋａｔ和Γ／ｎ的乘积与土壤理化性质的相关性进行了分析,并探讨乙草胺和异丙甲草胺在腐殖酸上的吸附机理。结果表明,乙草胺和异丙甲草胺在土壤中吸附主要受土壤有机质支配,有机质含含量越高越有利于这两种除草剂在土壤上的吸附。异丙甲草胺在土壤中的吸附明显弱于乙草胺。氢键是乙 相似文献
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The effect of a mixed fungal culture on the degradation of the herbicide metolachlor in soil was evaluated. Metolachlor was found to degrade up to 92% and 87% after 20 days in sterile and nonsterile soils respectively, when inoculated with a mixed culture of Aspergillus flavus and Aspergillus terricola and treated with 20 g g–1 metolachlor. When the soil was treated at 50 g g–1 level, 84% of the added herbicide degraded in inoculated sterile soil and 80% in nonsterile soil. The half-lives of metolachlor were found to be 5 and 4 times faster at the 20 and 50 g g–1 levels, respectively, in the presence of the mixed fungal culture. In treated soils, four metabolites could be identified by RP-HPLC. 相似文献
8.
Biodegradation of metolachlor in a soil perfusion experiment 总被引：2，自引：0，他引：2
Summary Degradation of the herbicide metachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] was studied in a soil perfusion system. After 28 days of perfusion, the 14CO2 evolved from a Virginia soil (soil A), which had been previously treated with metolachlor (Dual) for 5 years, accounted for 18.4% of the added 14C-metolachlor, while only 3.5% of the 14C was liberated as 14CO2 from a soil of the same field which had no history of Dual treatment (soil B). No 14CO2 was liberated from -irradiated soil A. After incubation, metolachlor constituted almost all the extractable 14C in sterile soil A, while about 20% of the added 14C extracted from non-sterile soil A consisted of products of metolachlor; 14.8% was identified as dechlorinated metolachlor. No mineralization occurred in actinomycete-inoculated sterile soil A, but 30% of the added 14C was recovered in the form of transformation products of metolachlor. Our results demonstrate clearly that microbial activity is responsible for the mineralization of metolachlor, and that degradation is enhanced in herbicide-acclimated soils. 相似文献
9.
Adsorption of atrazine and metolachlor in three soils from Blue Creek wetlands, Waterville, Ohio 总被引：1，自引：0，他引：1
Atrazine and metolachlor are extensively used pesticides in agricultural activities in northwest Ohio. Adsorption coefficients are often used to model pesticide fate and transport. Many physical-chemical parameters, such as organic matter, clay content, pH, and ionic strength, affect pesticide adsorption. Adsorption kinetics and adsorption isotherms were studied by batch experiment. Effects of humic acid, solution pH, and ionic strength on atrazine and metolachlor adsorption were also approached. After 24 h, both atrazine and metolachlor reached adsorption equilibrium in three local soils. Adsorption isotherms were described by Freundlich equations. The Freundlich coefficient (Kf) ranged from 0.14 to 4.47 (L kg–1) for atrazine, and 0.04 to 5.30 (L kg–1) for metolachlor. Adsorption capacity decreased in the order Sloan loam > Del Rey loam > Ottokee fine sand. Koc values varied considerably for both pesticides: metolachlor > in Sloan loam, atrazine metolachlor in Del Rey loam, and atrazine > metolachlor in Ottokee fine sand. In addition to organic matter content, clay played a key role in adsorption in the Del Rey loam and Ottokee fine sand. Higher adsorption was observed at pH 5 for both pesticides. As pH decreased to 3 and increased to 11, adsorption decreased. Adsorption increased as ionic strength increased. 相似文献
10.
为了解异丙甲草胺对植烟土壤微生物区系的毒性效应,本文采用室内模拟法研究了异丙甲草胺对植烟土壤微生物种群数量及生物活性的影响.结果表明:异丙甲草胺胁迫下,土壤微生物种群的动态变化取决于施用剂量、微生物种类和培养时间.试验期内,真菌对异丙甲草胺最为敏感,细菌次之,放线茵则具有一定的抗性.异丙甲草胺在14 d前对土壤呼吸均有不同程度的刺激作用,随后土壤呼吸强度呈现恢复或抑制的变化趋势.根据农药危害系数法的分级方法计算,异丙甲草胺对植烟土壤微生物属于无实际毒害的农药. 相似文献