Resistance Physiological Mechanism Of Chrysopogon Aciculatus(Retz.)to Fenoxaprop-p-ethyl

Chrysopogon aciculatus(Retz.)Trin.is a perennial Gramineae tropical turfgrass.At present,C.aciculatus has been many studied by researchers.However,the research on herbicide resistance of C.aciculatus has not been reported yet.In order to control lawn weeds,sixty-two C.aciculatus accessions were used as materials to explore the physiological mechanism of the herbicide-resistant of ACCase.The results were as follows:1.Seven common herbicides were used to treat C.aciculatus and Bermuda grass It was found that C.aciculatus had a certain resistance to fenoxaprop-P-ethyl,but the weed Bermuda grass had no resistance.Therefore,in the follow-up experiments,fenoxaprop-P-ethyl were selected as the treatment agent.2.Different gradients of carbendazim were applied to test the damage degree of C.Aciculatusand the relative content of chlorophyll(SPAD value).The effect of 75 g ai ha-1 and 100 g ai ha-1 of fenoxaprop-P-ethyl on C aciculatus was significant(P<0.05),which was difference between 25 g ai ha-1 and 50 g ai ha-1.There were not significant(P>0.05)between 75 g ai ha-1 and 100 g ai ha-1.Therefore,75 g ai ha-1 was selected as the optimal dose.3.Sixty-two C.aciculatus accessions collected from Fujian,Guangdong,Guangxi,Yunnan and Hainan provinces were treated by 75 g ai ha-1,According to the results of apparent observation of damage and relative content of chlorophyll,the membership function analysis showed that the biotype with strong resistance was R-type CA22 and the biotype with weak resistance was S-type CA73.The ED50 concentration of CA22 is 223.5 g ai ha-1,and that of CA73 is 45.27 g ai ha-1.Evaluate the physiology diffenerce,such as Malondialdehyde(MDA),glutathione transferase(GSTs)and cytochrome(P450)between CA22 and A73.The resulted showed after spraying 75 g ai ha-1.The results showed that the content of MDA in CA22 and CA73 was not significantly different(P<0.05),but the content of MDA was the highest on the 8th day of CA73,and the reaction time was faster,indicating that fenoxapropion was more sensitive to the pharmacodynamic response of CA73.The damage is more serious.The activity of GSTs in the CA22 treatment group was higher than that in the control group of CA22 on the 12th day,and the difference between the two groups was not significant(P>0.05),but the GSTs activity of the CA73 control group did not change significantly(P>0.05),and CA73.The GSTs activity of the treatment group was extremely significant(P<0.01),especially at 20th day,the GSTs activity of CA73 tended to be 0.The P450 activity of CA22 decreased first and then increased with the time interval of drug efficacy.From the 10th day,the treatment group was higher than the control group of CA22,and maintained high P450 activity.The P450 activity of CA73 was significantly lower than that of the control group of CA73,and the activity was lower,which was significantly different from that of CA22(P<0.05).The comprehensive physiological evaluation showed that the resistance of CA22 is 4.94 times higher than that of CA73.4.P450 metabolic resistance of CA22 was significant reversed(P<0.05)and reduced P450 content(P<0.05)by using fenoxaprop-P-ethyl insecticide and Phorate together.However,there was no significant difference in the P450 between the presence or absence of the Phorate in the CA73(P>0.05).