【作者】 刘英华；

【导师】 王开运；

【作者基本信息】 山东农业大学 ， 农药学， 2003， 硕士

【摘要】 本研究利用戊唑醇、井冈霉素、丙环唑、噁醚唑、咯菌腈5种药剂对小麦纹枯病菌进行室内抗性选育；研究了各菌系的抗性发展规律；并测定了各抗性菌系对几种常用药剂的交互抗性；系统研究了不同抗性菌系在生长速率、菌丝干重、致病性、产菌核能力等生物学差异，不同抗性菌系对不同PH值的敏感性及不同光照条件对其生长的影响；并对戊唑醇菌系的抗性机理进行了初步的探讨。结果说明：1、 纹枯病菌对5种药剂的抗性发展速度均较快，室内选育到36代，对戊唑醇的抗性增加到33.37倍，对井冈霉素的抗性增加到49.24倍，对丙环唑的抗性增加到33.26，对噁醚唑的抗性增加到39.96倍，对咯菌腈的抗性增加到20.04倍，均已经形成了较高的抗性菌系。通过对各抗性菌系进行遗传稳定性测定，发现各菌系在无药培养基上转代培养8代以后，其生长速率变化较小，抗性稳定性较强。2、 不同抗性菌系对其它药剂的交互抗性为：抗井冈霉素菌系对丙环唑和噁醚唑的抗性分别达10.95倍和48.58倍，交互抗性显著；对戊唑醇和咯菌腈的抗性分别为2.55倍和1.78倍，交互抗性水平较低。抗戊唑醇菌系对三唑酮、丙环唑、井冈霉素、福美双和噁醚唑的抗性分别为31.2倍、22.8倍、16.9倍、15.8倍和15.5倍，交互抗性显著；对咯菌腈的抗性仅为1.6倍，交互抗性略有提高。抗丙环唑菌系对戊唑醇、井冈霉素、噁醚唑的抗性分别为11.83倍、23.26倍、21.38倍，交互抗性显著；对咯菌腈的抗性为0.316倍，表现出负交互抗性现象。抗噁醚唑菌系对丙环唑、戊唑醇、井冈霉素的抗性倍数分别为56.45倍、25.48倍、46.10倍，交互抗性显著；对咯菌腈抗性为0.75倍，也表现出一定负交互抗性现象。抗咯菌腈菌系对戊唑醇和井冈霉素的抗性分别为3.42倍和2.87倍，交互抗性明显；对丙环唑和噁醚唑抗性分别为0.65倍和0.76倍，也呈现负交互抗性现象。<WP=7>3、 在生物学特性上，敏感菌系的菌丝生长速率、菌丝干重均大于5个抗性菌系；抗性菌系的致病力、产菌核能力均强于敏感菌系；抗性菌系和敏感菌系对酸碱度、光照反应差异不明显。4、 敏感菌系在低渗透压下较抗性菌系敏感，而各抗性菌系在高渗透压下较敏感菌系敏感，说明各抗性菌体质膜功能均发生变化。5、 抗戊唑醇菌系合成麦角甾醇的能力比敏感菌系强，且戊唑醇对敏感菌系麦角甾醇合成能力的抑制程度明显大于对抗性菌系的抑制程度，戊唑醇浓度为0.5μg/ml 时，对敏感菌系麦角甾醇合成的抑制率为41.94%，而对抗性菌系的抑制率仅为20.37%；当戊唑醇浓度为0.1μg/ml时，对敏感菌系麦角甾醇合成的抑制率为32.05%，而对抗性菌系抑制率仅为8.43%。6、 酯酶同工酶电泳酶谱显示，敏感菌系与抗戊唑醇菌系均有5条比较明显的谱带，两菌系中5条酶带的Rf值均相同，只是Rf=0.56的酶带抗性菌系颜色比敏感菌系深，该抗性菌系的酯酶仅发生了量的变化，尚未表现出质的变化。7、 接种各抗性菌系和敏感菌系后，小麦植株过氧化物酶和多酚氧化酶活性均发生了变化，其中接种敏感菌系的小麦植株过氧化物酶和多酚氧化酶的活性变化较大，而接种抗性菌系的各植株酶活性变化相对较小，证明在小麦苗期敏感菌系致病力强，引起的病害较重，使植株发生相应的抗性反应。更多还原

【Abstract】 The purpose of this paper is to evaluate the risk of resistance in Rhizoctonia cerealis to fungicides. In the study the resistance selection of Rhizoctonia cerealis to tebuconazole、validamycin、propiconazole、difenoconazle、fludioxoni and also the cross-resistance of each resistant strain were carried out; Then the difference on some biological characters such as the growth rate and dry weight of the mycelium、pathogenicity and the capacity of producing sclerotia were studied; The inhibition of PH and irradiate on sensitive and resistant strains was also studied;At last the resistance mechanism was studied. The results could be summaried as follows:1.The studies of resistance selection showed the resistance of Rhizoctonia cerealis had reached 33.37 fold to tebuconazole, 49.24 fold to validamycin, 33.26 fold to propiconazole, 39.96 fold to difenoconazle and 20.04 fold to fludioxoni after treated 36-time in the laboratory. After 8 successive incubation on the free-fungicide PDA, the resistant strains could maintain their resistance.2.The cross-resistance of each resistant strain to fungicides was as follows: The R-validamycin strain had high positive resistance to propiconazole and difenoconazle,the resistance to propiconazole and difenoconazle were 10.95 fold and 48.58 fold respectively, while had little influence on the resistance to tebuconazole and fludioxoni,the resistance were 2.55 fold and 1.78 fold respectively; The R-tebuconazole strain had high positive resistance to triadimefon、propiconazole、validamycin、thiram and difenoconazole, the resistance were 31.2 fold、22.8 fold、16.9 fold、15.8 fold<WP=9>and 15.5 fold respectively, while the resistance to fludioxoni was only 1.6 fold; The resistance of R- propiconazole to tebuconazole、validamycin、difenoconazole were 11.83 fold、23.26 fold、21.38 fold respectively, while had negative resistance to fludioxoni, the resistance was 0.316 fold; The resistance of R- difenoconazole strain to propiconazole、tebuconazole、vacidamycin were 56.45 fold、25.48 fold and 46.10 fold respectively, the resistance to fludioxoni was 0.75 fold, also had negative resistance; The resistance of R- fludioxoni strain to tebuconazole and validamycin were 3.42 fold and 2.87 fold, had negative resistance to propiconazole and difenoconazole, the resistance were 0.65 fold and 0.76 fold respectively.3.In biological characters, the sensitive strain had higher growth rate and dry weight than resistant strains; The resistant strains had higher pathogenicity and produced more sclerote than sensitive strain. The sensitive and resistant strains showed little differences in inhibition of pH and irradiate.4.The sensitive strain was more sensitive than resistant strains in low osmotice pressure. But when the osmotice pressure was high ,the resistant strains were more sensitive than strains, the result showed that the function of the cell membrane of resistant strains were changed.5.Ergosterol yields of R-tebuconazole strain was higher than that of sensitive strain, and the inhibition rate of tebuconazole to sensitive strain was higher than to resistant strain. At concentration of 0.5 ug/ml, the inhibition rate to sensitive strain was 41.94%, while to resistant strain was only 20.37%; At concentration 0.1 ug/ml, the inhibition rate to sensitive strain was 32.05%, while to resisant strain was only 8.43%.6.The esterase isoenzyme zymogram showed that the sensitive strain and R-tebuconazole strain all have five obvious enzyme bands. The difference of the color of the band whose Rf was 0.56 shows that the resistance of Rhizoctonia cerealis to tebuconazole was concerned with the changes of esterase.<WP=10>7.After inoculated the sensitive and resistant strains respectively, the activities of peroxidase(POD) and polyphenol oxidase(PPO) were all changed ; after inoculated the sensitive strain, the activities of POD and PPO of wheat were increased more than that inoculated resistant strains. The result showed that the sensitive strains had higher pathogenicity to wheat seedli更多还原