【作者】 付仲文；

【导师】 张朝贤；

【作者基本信息】 中国农业科学院 ， 农药学， 2000， 硕士

【摘要】 本论文测定了我国部分稻田稗草对丁草胺的抗药性，并对其产生机理从代谢角度进行了初步探讨。 在湖北，黑龙江等地调查发现田间用丁草胺防除稗草的效果明显不如以前。本文以华中地区三种群岳阳（未使用过丁草胺）、湖北漳湖垸农场3队（使用丁草胺14年）、湖北漳湖垸农场4队（使用丁草胺18年），东北地区三种群牡丹江（未使用过丁草胺）、民主（使用丁草胺10年）、阿城（使用丁草胺14年）为研究对象，运用室内盆栽生物测定方法研究了其抗药性现状。试验结果表明，LC₅₀值以岳阳种群最小，牡丹江种群最大，分别为54.73g a.i./ha和1271.6g a.i./ha；敏感性由高至低依次为：岳阳、阿城、3队、民主、4队、牡丹江。以岳阳种群为参照，阿城、3队、民主、4队稗草种群的抗药性系数分别为5.21、5.85、8.00、12.01，表明长期用药使其产生了对丁草胺的抗药性。而牡丹江种群种子粒大，千粒重较其它种群显著高，加上可能由于其它除稗剂禾大壮、二氯喹啉酸等的使用，使其具有获得抗性（或耐药性）的可能。 本文还应用生物化学方法，选择了三个苗龄的稗草来测定各种群幼苗中GSTs酶活和GSH、Cysteine等自由巯基的含量，初步研究了它们分别与LC₅₀值之间的相关性。结果表明：（1）当用5ppm丁草胺处理稗草幼苗48小时时，酶活有不同程度的提高。GSH、半胱氨酸含量差异显著，其中，南方处理种群GSH含量与LC₅₀值之间正相关，北方处理种群Cysteine含量与LC₅₀值之间呈负相关。（2）而用5ppm丁草胺处理9天的稗草，处理种群与未处理种群比较，其酶活有不同程度地提高（阿城种群例外），但各种群酶活与其生测的致死中量LC₅₀值之间未表现出线性相关性。各未处理种群之间GSH含量差异极其显著，它们与LC₅₀值之间的线性拟合方程为y=0.0321x+25.029（R²=0.8382）。（3）种植14天的稗苗，未用药剂处理，酶活表现出一定的规律性，即：酶活与LC₅₀值的关系，华中种群为正相关，北方种群为负相关。而南方种群幼苗GSH含量与LC₅₀值有正相关趋势，北方种群幼苗GSH含量与LC₅₀值有负相关趋势。（4）测定GST专一性酶活结果表明，所采用的方法未检测到GS-丁草胺，可能是与GST酶对甲草胺、乙草胺、异丙甲草胺的专一性酶活相比，对丁草胺的酶活较低，这与Scarponi（1991年）报道的结果一致，其专一性酶活的测定方法需 稻山稗草对丁芋胺的抗性测定及机理初步Uf究进一步探索。而体外轭合实验表明，在一定条件下非酶结合是可以实现的，这己通过TLC和质谱获得证实。 总之，田间调查和室内生物测定结果表明我国部分稻田稗草对丁草胺已产生不同程度的抗药性。通过GST酶活的测定以及簿层层析和质谱分析表明GST酶代谢丁草胺解毒是其抗或耐药性的机制之一。抗或耐丁草胺的稗草种群GSH等自由疏基含量和酶活有显著提高，酶活或GSH含量同LC。。值己表现出一定的相关性，但南方种群与北方种群相关性表现不一致，可能与气候、土壤等环境条件、作物种植管理水平不同、丁草胺的特殊结构及抗性水平有关：稗草对丁草胺的抗药性机制还可从其它途径进行研究。更多还原

【Abstract】 The present status of butachlor resistance of Echinochlor crus- galli(L.)Beauv.(CE) occurring in paddy rice in north and south of China was studied, and the resistant mechanism from the point of metabolism was studied. With continuing application of butachlor in the fields of Hubei and I-Ieilongjiang Provinces, it was noticed that the herbicidal efficacy for controlling EC was reduced. Seeds of different EC populations collected from 6 sites (Yueyang, no butachlor applied, Team III on Zhanghuyuan Farm with 14-year application of butachlor, Team IV on Zhanghuyuan Farm with 18-year application of butachlor in the south; Mudanjiang, no butachlor applied, Minzhu with 10-year application of butachlor, Acheng with 1 4-year application of butachlor in the north)were tested to evaluate butachlor resistant status in the areas. It was revealed that LC~0 for controlling of Yueyang population was the lowest, that of Mudanjiang population was the highest among the six populations, 54.73 g a.i./ha and 1271.6 g a.i.Iha respectively. The order of sensitivity of the populations from high to low ranged: Yuyang, Acheng, Team III, Minzhu, Team IV, Mudanjiang. Using Yuyang population as the control, RI indexes of other populations excluding Mudanjiang population were Acheng 5.21, Team III 5.85, Minzhu 8.00, Team IV 12.01, which indicated that the four populations had evolved resistance to bubachlor. Three seedling stages was selected to test glutathione S-transferase(GST) activity and the amount of GSH, cysteine, and whether it was correlative with LC50 values were studied. Biochemical tests showed that (1) when the seedlings of EC were treated with butachlor (5 ppm) for 48 hours, GSTs activities increased, the amount of GSH, cysteine show significant difference. The amount of GSH of treated populations was positively correlative to LC0 for controlling of the populations in the south, the amount of Cysteine of treated populations was negatively correlative to LC50 in the north. (2) The seedlings of EC were treated with butachlor (Sppm) for 9 days, compared to the untreated populations, the GSTs (CDNB) activities of eachtreated population were higher with exception of Acheng population, but the amountof GSH varied significantly according to the different populations. There was lineartrend between the GSH and LC, i.e. y=0.032l+25.029 (R2=0.8382). (3) GSTsactivity and the amount of GSH of the unbeated seedlings grown for l4 days showedpositive correlation to LC,, for controlling of the POpulations in the southrespectively, but negative correlation to LC,, of those in the north. Although GS-butachlor was not found in vivo study, it was confirmed in vitro conjugating tests byTLC and mass spectrum techniques. The free thiols and GSTs activities to CDNB inEC populations indicatCd that butachlor resistance in EC was increased notably.GSTs activity or the amoun of GSH showed direct correlation with the LC,, fOrcontrolling of different poPulations to some extent. It is suggested that the analysismethod needs to be improved, studying of other possible mechanism is needed.更多还原