Herbicidal Activity And Characteristics Of A Novel PPO Inhibitor-Y11049

In recent years,due to the increasing problems of resistance and safety of herbicides registered on non-arable land in China,the research and development of new herbicides with exfoliative properties has attracted more and more attention.The novel compound Y11049 was used protoporphyrinogen oxidase（PPO）as the target of oxidase.In order to investigate the action characteristics of Y11049,the effect of herbicidal spectrum,toxicity curve,environmental factors（temperature,light intensity,rainfall）on its herbicidal activity and its action characteristics（absorption conductivity,appropriate application period）were studied under greenhouse conditions.The mechanism of action of Y11049 and its influence on some biochemical indexes of plants were discussed to provide theoretical and practical basis for its development and application.The experimental results are as follows:1.In greenhouse,Y11049 displayed a wide spectrum against 37 species of weeds for 80%～100%at 60g a.i./hm².The value of ED₉₀ against Portulaca oleracea,Cyperus difformis and Echinochloa crusgalli were 19.68 g a.i./hm²,18.27 g a.i./hm²and 98.28 g a.i./hm²,respectively.2.In field,Y11049 showed high efficacy against non-cultivated broadleaf grass （93.14%）and sebage（87.62%）at 120g a.i./hm² while the inhibition rate against gramineous weeds was lower.Furthermore,Y11049 revealed good rapidity and contact activity.3.The test of environmental factors showed that the herbicidal activity of Y11049 was positively correlated with the 15℃～35℃temperature at 30 g a.i./hm².Under the condition of full light（8427lux）,the fresh weight inhibition rate at 60g a.i./hm² of Y11049 was 95.22%,which was significantly higher than that under medium light（4200lux）and low light（5lux）,suggesting light is a prerequisite for Y11049.The simulated rainfall was applied after 4 h of the spray of Y11049,the inhibition rate P.nil still reached to 90%～100%,which indicated that Y11049 was tolerant to rain-washing.4.The action characteristics showed that the soil treatment before buds of Y11049had no activity on the test targets,and the inhibition rate against 2,4,6 and 8-leaf Abutilon theophrasti and Amaranthus retroflexus at 30 g a.i./hm² were 86%～98.6%and 86.81%～96.17%,respectively,suggesting that Y11049 has a relative long application period.What’s more,Y11049 can be absorbed into plants through roots,stems and leaves,with poor conduction ability.5.The results show that Y11049 of 7.5 g a.i./hm² causes irreversible damage to the cell membrane of the abutilon theophrasti leaf and the chloroplast structure is destroyed and the plant can not carry out photosynthesis.It was also found that MDA content,chlorophyll content,POD activity,SOD activity and some fluorescence parameters of the plants were abnormal.