| Rice is the most important food crop in our country,Its fertility and abundant harvest have a decisive effect on the increase of grain production in our country,Echinochloa crus-galli is one of the most common and harmful weeds in rice production in China,it seriously affects the rice yield of our country.Due to the long continuous cropping in most rice producing regions in our country,single herbicide varieties were continuously used,weed has enhanced the resistance to common herbicides,the occurrence of weed resistance has become the main factor restricting the production of rice in China.Quinclorac is the most commonly used herbicide in rice fields,because of continuous use,the weeds was more resistant to it.In this paper,the degree of resistance of different species of weed to quinclorac was studied by bioassay,the resistance mechanism of different species of weed to quinclorac was studied by means of physiological,biochemical analysis methods,the physiological and biochemical mechanism of the resistance of the grass to quinclorac was studied systematically.A new type of quinclorac compounds were synthesized and their biological activity were determined,by study the control effect of different resistant weeds,to provide theoretical and practical basis for reasonable control resistance weed in paddy field.The main results were as follows:1.The differences of the resistance of different species of weeds to quinclorac were determined by biometric method.Among them,the Shuangyashan welfare,Haiqing Fuyuantongjiang and other four areas were the most sensitive to quinclorac,and the resistance index was less than 5,four regions,such as Qiqihar,Huachuan Suiling are in the low level of resistance and the resistance index is 5?10,the five regions,such as Fujin,Tangyuan,Yanshou are in the moderate resistance level and the resistance index is 10?20,in the three areas,such as Tongjiang,Huanan and Jiansanjiang,the grass reached a high level of resistance and the resistance index was greater than 20.The number of years of using quinclorac are different,there are obvious differences in the resistance of weeds,the sensitive weeds to quinclorac are in the area of used quinclorac under four years,it was achieve moderate resistance level of quinclorac,where used quinclora more than seven years,the most resistance level is the grass in Jiansanjiang and Tonghe area,which has been used quinclorac for more than 10 years,moreover,the resistance of weed to quinclorac gradually increased with the extension of used life.2.The different resistant weeds under the stress of quinclorac,the activity of the two kinds of protective enzymes such as SOD and POD could be reduced briefly,then the activity would rise,and the fifth day would be highest,the increase of the high-resistant grasses was significantly higher than that of the sensitive grasses,then the enzyme activity of SOD and POD began to decrease,however,the population of high-resistant grass was lower than that of the sensitive weeds,it is suggested that the resistance mechanism of weed to quinclorac is related to the activity changes of these two protective enzymes,the more active the grass,the stronger the resistance.3.The weed under the stress of quinclorac,the activity of CAT enzyme in grass plants began to increase,the fifth day reaches the highest,and then it comes down,and the increase of activity was significantly higher than that of the sensitive weed population,the decrease rate of CAT activity of resistant weed was also lower than that of the sensitive weed population,so,the stronger the activity of CAT enzyme,the stronger the resistance to quinclorac.4.MDA content in grass plants gradually increased in the three days prior to the stress of quinclorac,then it comes down,and the increase of resistant grass was significantly lower than that of the sensitive weed,it is suggested that the lower the MDA content,the stronger the resistance of weed to quinclorac.5.The content of GSH and the activity of GST in weed plant under the stress of quinclorac,has a tendency to decrease first and then rise,the GSH content of high-resistant weed was significantly less than that of the sensitive weed.Although the GST activity decreased under the stress of quinclorac,the changing amplitude of GST activity of the high-resistant grasses was significantly lower than that of the sensitive weed,it shows that the activity of metabolic enzyme GST is one of the reasons for the resistance to chlorquinoline in plant biochemistry.6.The different resistant weeds under the stress of quinclorac,the gene expression of CAT and GST were obvious different.Among them,the expression of CAT showed the trend of first increase and then decrease,the fifth day reached its highest point,the increase of CAT expression of high-resistant weed grass was significantly higher than that of the sensitive weed,the higher the expression of CAT gene,the stronger the resistance of weed.Under the stress of quinclorac,the expression of GST showed a tendency to decrease and then increase,the amplitude of GST expression of high-resistant weeds was significantly less than that of the sensitive weed,the higher the expression of GST enzyme,the stronger the resistance.7.Under the stress of quinclorac,there was a significant difference in the content of IAA and ABA in the high-resistant weed and the sensitive weed plants.The content of growth hormone(IAA)in the high-resistant weed plant was decreased,but the IAA content of the sensitive grass grass increased.Under the stress of quinclorac,the content of abscisic acid(ABA)in the grass was increased and then decreased,at the fifth day reached the highest,the increase of ABA content of high-resistant weeds was significantly smaller than that of the sensitive weed.8.The different resistant weeds under the stress of quinclorac,there was a significant difference in the content of ZR and JA in the weed,the content of ZR in the plant was reduced first and then increased,the fifth day was the lowest,the decrease of ZR content of high-resistant weed grass was significantly less than that of the sensitive weed.Under the stress of quinclorac,the content of jasmine acid(JA)in weed plant was increased and then decreased,the rise amplitude of the JA content of high-resistant weed was significantly lower than that of the sensitive weed.9.Quinclorac was used as substrate,with methanol,ethanol and isopropanol,catalyzed by sulfoxide,made a full response,got a couple of compounds,the highest yield was 77.2%of the 3,7-dichloroquinoline-8 carboxylate methy ester,the highest yield was 89.4%of the 3,7-dichloroquinoline-8 carboxylate and the highest yield was 64.8%of the 3,7-dichloroquinoline-8 carboxylic acid isopropyl.The biological activity of isopropyl dichloroquinoline is the highest,the control effect of antagonistic weed was significantly higher than that of quinclorac,the isopropyl and cyhalofop-butyl mixed can control resistant weed very well,both plant control effect and fresh weight control effect exceed 90%.Lastly,the innovative of the research1.The gene expression of CAT enzyme and GST enzymes of different resistant grasses were studied by molecular biology methods,the differences of expression of several enzymes in the different resistance levels were clarified.Under the stress of quinclorac,the expression of CAT is increased and then decreased,the increase of CAT expression of high-resistant weed grass was significantly higher than that of the sensitive weed.Under the stress of quinclorac,the GST expressions were reduced first and then raised,the variation of GST expression of high-resistant weeds was significantly less than that of the sensitive weed.2.The content variation rule of auxin(IAA),abscisic acid(ABA),gibberellin(GA),zeatin riboside(ZR)and jasmonic acid(JA)were determined by ELISA method,under the stress of quinclorac,the change of several hormones of high-resistant weed was significantly less than that of the sensitive weed,it shows that quinclorac can cause the death of weeds by disrupting hormone changes.3.A series of dichloroquinoline acid homologues were synthesized by means of chemical synthesis,the biological activity of 3,7-dichloroquinoline-8 carboxylic acid isopropyl is the highest,the control effect of antagonistic weed was significantly higher than that of quinclorac,the isopropyl and cyhalofop-butyl mixed were able to achieve good effect on resistant grass. |
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