【作者】 马国兰；

【导师】 柏连阳； 余柳青；

【作者基本信息】 湖南农业大学 ， 农药学， 2013， 博士

【摘要】 稗草Echinochloa crusgalli(L.).Beaiv.)是我国水稻产区最主要的恶性杂草之一,而二氯喹啉酸是我国水稻田长期使用的经济、有效、安全的除稗剂。抗二氯喹啉酸的稗草种群已严重影响了水稻的安全生产。本研究以我国长江中下游稻区稻田稗草为对象,采用室内整株生物测定法测定了42个稗草样品对二氯喹啉酸的抗药性水平,筛选出抗药性水平高的两个抗药性生物型稗草,并以其为试验材料,分析了其对6种常用新型除稗剂的多抗药性；通过生理生化方法,研究了不同生物型稗草经二氯喹啉酸处理后,体内ACS合成酶和解毒酶p-CAS的活性差异；通过分子生物学技术对不同生物型稗草ACS基因进行了初步分析；利用了筛选出的3个除草剂配方组合对抗药性稗草进行了田间防治。结论如下：1、整株生物测定结果表明,我国长江中下游稻区稗草对二氯喹啉酸均存在不同程度的抗药性。其中以湖南益阳芷湖口镇和望城县的二个生物型稗草对二氯喹啉酸抗药性的水平最高,抗药性指数高达21.84和32.31。其EDso分别为1651.4857g a i/hm2和2443.4517g ai/hm2。湖南省其它地区、浙江、江苏省二氯喹啉酸对稗草的抗药性水平较低,抗药性指数在1.30-7.32之间。对抗药性水平严重的湖南益阳芷湖口镇R1和望城县R2两生物型稗草第二代进行了二氯喹啉的抗药性检测,结果表明,稗草对二氯喹啉酸的抗药性能够通过下一代稳定遗传。2、本试验发现,经二氯喹啉酸处理后,稗草抗药性生物型R1、R2和敏感生物型S的ACS活性变化明显不同。在抗药性生物型R1、R2体内合成酶ACS不能被诱导,活性未能升高反而降低,始终维持在同期对照水平之下。而S生物型中,ACS被诱导,活性升高；两R生物型的解毒酶β-CAS活性升高,处理后5d β-CAS活性到达最高值,分别为同期对照的1.80倍和2.05倍；而S生物型的β-CAS活力先呈小幅下降,至5d降至最低值,为同期对照的0.74倍。3、采用基因同源序列法对抗药性和敏感性生物型稗草的ACS基因进行扩增和序列分析,获得了拼接后总长度为987bp,共编码329个氨基酸ACS基因的cDNA保守区序列片段。不同生物型稗草ACS基因保守区的氨基酸序列相同,并未发生突变。由于本研究未对ACS基因的全长进行分析,除保守区外的其它部分是否有基因突变也不清楚,有待于进一步研究。4、在非竞争条件下,敏感性生物型稗草S在植株高度、植株鲜重、根长、根鲜重和叶片宽度方面都明显高于抗药性生物型稗草R。但在叶片的数量方面两者无显著差异性。5、抗药性生物型稗草R1、R2对四种ALS抑制剂五氟磺草胺、双草醚、嘧啶肟草醚、氟毗磺隆以及二种ACCase抑制剂噁唑酰草胺、氰氟草酯的多抗药性测定结果表明,六种供试除草剂均对抗药性生物型稗草R1、R2具有良好的防治效果。盆栽试验和田间试验的结果均表明抗二氯喹啉酸的生物型稗草对上述六种常用的稻田除稗剂敏感,并无多抗药性产生。6、在洞庭湖稻区抗药性杂草发生较严重地区,应用3种不同除草剂配方组合轮换使用来防除抗药性稗草,三年的试验结果均表明：该地区的稗草对二氯喹啉酸已经产生了抗药性,二氯喹啉酸应在该地区停止使用；除草剂配方组合1、2、3对抗药性稗草及其杂草群落的防效均在90%以上,对水稻安全。在不同年份轮换使用可使抗药性稗草能够得到有效防治,且可避免或延缓新的抗药性稗草的发生和发展。更多还原

【Abstract】 Barnyardgrass [Echinochloa crusgalli (L.) Beauv] is the most troublesome weed in rice in China. Quinclorac is one of the most excellent herbicides for barnyardgrass control in the rice field with good safety, high efficacy and low price. The occurrence of barnyardgrass resistance to quinclorac constitutes a major thread in rice yield safety. It is very necessary to confirm barnyardgrass resistance level and its mechanism to quinclorac, in order to effectively control barnyardgrass and prolong the lifespan of quinclorac in practice. Barnyardgrass seeds were collected from rice field of Hunan, Zhejiang and Jiangsu provinces The sensitivity of Barnyardgrass to Quinclorac was determined by pot planting experiments in the greenhouse, its resistant level and mechanism were also conducted. The results were obtained as followings.1. The resistance of Barnyardgrass to quinclorac were determined by using pot planting method for42populations of barnyardgrass, which were collected from the rice regions around middle and lower area of Yangtze river of China during2008to2011. The results showed that higher resistance levels were observed in two biotypes of barnyardgrass from Zhihukou Town in Yiyang County (R1) and Wangcheng County (R2), Hunan Province, and the resistance indexes were21.84and32.31fold, respectively. There were less resistance levels (1.12-7.32fold) in other populations of barnyardgrass in other rice regions of Hunan, Jiangsu and Zhejiang Province. R1and R2biotype were harvested and were conducted by whole plant experiments in potted in the greenhouse next year. The results revealed that the two biotypes still showed high level resistance level, Which suggested that the resistance of barnyardgrass could be inherited.2. The1-aminocyclopropane-1-carboxylate synthase (ACS) activities in two resistance biotypes of barnyardgrass (R1and R2) were inhibited significantly which was lower than that in sensitive biotype (S) at1st day after treated by quinclorac, the two RIs were0.49and0.56fold compared with the contemporary control, respectively. Both of them increased slightly at2nd days and were still lower than that in the control; however they decreased slowly to0.34-and0.35-fold relative to the control at4th days The β-cyanoalanine (β-CAS) activities in R1and R2of barnyardgrass increased significantly after treated by quinclorac; the maximum were observed at5th days, which were1.80and2.05-fold, compared with the control respectively.3. DNA sequence of barnyardgrass ACS gene was amplified, cloned and compared between resistant and susceptible biotype. The length ACS gene were987nucleotides which was approximately translated into329amino acids. The amino acids sequences of the susceptible and resistant biotypes were consistent. No mutations were found in the resistant biotypes of R1and R2.4. Under the condition of the non-competition, The plant height, the weight of the plant aerial part, the root length, the root weight and the breadth of leaf of sensitive biotype barnyardgrass is better than that of two resistant biotypes. Different biotypes were not significantly different from the number leaf of Barnyardgrass.5. Pot planting experiments in the greenhouse and field experiments were conducted to other six herbicides to control barnyardgrass, which are penoxsulam, bispyribac-sodium, pyribenzoxim, flucetosulfuron, Metamifop, cyhalofop-butyl. The reults showed that the six herbicides could effectively control barnyardgrass and did not show any across-resistance with Quinclorac. All of them gave very good barnyardgrass control.6. The different herbicides combinations were used to control the resistance weed in direct seeding rice fields in the region of Dongting Lake in2009-2011. The results showed that barnyardgrass were resistant to quinclorac in the area, which only provided53.1%of barnyardgrass plant density control and65.5%of barnyardgrass plant fresh weight control. The three combination herbicides of1,2,3gave excellent control effect to resistance barnyardgrass and its population.The control effect was more than90%to the weed in two years experiments. The three combination herbicides were used with ring application form in different years and to avoid or delay appearing of new resistance weeds. So that the three combination herbicides should be extension promoting in direct seeding rice area of Dongting Lake.更多还原