Physiological Resistance Mechanism Of Foxtail Millet With Different Herbicide-resistance To Monosulfuron And Prometryn

There are different herbicides-resistances whether different foxtail millet varieties with treatment of the same herbicide or the same foxtail millet variety with treatment of different herbicides.The objective of this experiment was to research the different response of foxtail millet to herbicide stress and provide a theoretical reference for further explore the resistance mechanism of foxtail millet to herbicide.This experiment was conducted with seven main planted varieties of foxtail millet which are Jingu 21,Jingu 29,Jingu 40,Jigu 38,Jigu 42,Yugu 28 and Yugu 35 as materials with treatment of monosulfuron and prometryn.And the foxtail millet variety with the greatest difference in herbicides-resistance from Jingu 21 was selected from six varieties,and the different response of physiological resistance mechanism was studied.There were 15 physiological and biochemical indicators determined,including the content of superoxide anion radical(O2-)and malondialdehyde(MDA),the activity of antioxidant enzymes superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),the content of antioxidant reduced ascorbic acid(As A),reduced glutathione(GSH),proline(Pro),soluble protein(SP),the content of chlorophyll(Chl)and carotenoid(Car),the activity of target enzyme acetyllactic acid synthase(ALS),metabolic enzyme glutathione transferase(GST)and cytochrome P450(CYP450).To compare and analyze the differences in expression of relatively resistant and sensitive varieties,the correlation among the indexes of the same variety of foxtail millet to know the physiological response of foxtail millet to herbicide stress.The results were as follows:1.The herbicides-resistance was comprehensively analyzed according to the biological indicators of seed germination after seven foxtail millet varieties were treated with different concentrations of monosulfuron and prometryn,and the result showed that there was the greatest difference in resistance to monosulfuron between Jingu 21 and Jigu 42 among the seven foxtail millet varieties,and the resistance of Jingu 21 to monosulfuron was significantly greater than Jigu 42.There was the largest difference in resistance to prometryn between Jingu 29 and Jingu 21,and Jingu 29 was significantly more resistant to promethoprim than Jingu 21.2.With the increase of monosulfuron concentration,the activity of SOD and POD in leaves of Jingu21 increased gradually.The SOD activity of Jigu 42 increased at first and then decreased,and the POD activity increased gradually,but the activity of two enzymes in Jigu 42 was always lower than Jingu 21.The activity of CAT in two foxtail millet varieties decreased at first and then increased with the increase of monosulfuron concentration.The activity of CAT in Jigu 42 was significantly lower than Jingu 21 under all concentrations,which indicated that the antioxidant capacity of protective enzymes in tolerant variety Jingu21 was significantly higher than the susceptible variety Jigu 42 with monosulfuron stress.The activity of CYP450 in two varieties increased at first and then decreased.The enzyme activity of Jigu 42 reached the maximum when the treatment concentration was 100 mg·L-1,while the maximum enzyme activity of Jingu21 appeared when the treatment concentration was 200 mg·L-1,indicating that the CYP450 of Jingu 21 still had a stronger metabolic detoxification effect on monosulfuron with high concentration stress.3.With the increase of the concentration of prometryn,the activity of SOD and POD in the leaves of Jingu29 increased,while the Jingu 21 decreased,indicating that the SOD and POD played a role in the process of resisting the prometryn of foxtail millet.The content of Pro in foxtail millet significantly increased with the treatment of prometryn,and the increase of Jingu 29 was significantly higher than Jingu21,indicating that Jingu 29 could maintain osmotic balance by increasing the content of osmotic regulators,reduce the damage of prometryn to cell membrane system,which showed the stronger drug resistance.With the treatment of different concentrations of prometryn,the activity of ALS,GST and CYP450 of Jingu 29 increased gradually and was always higher than Jingu 21,indicating that the detoxification ability of metabolic enzymes of Jingu 29 was stronger than Jingu 21.4.Jingu 21 was resistant to monosulfuron and sensitive to prometryn stress.The physiological responses of Jingu 21 to different herbicides were analyzed and compared,the results showed that prometryn stress significantly inhibited the activity of SOD,POD and CAT of Jingu 21,while monosulfuron treatment increased the activity of SDO and POD,indicating that antioxidant enzymes were involved in the resistance response of foxtail millet to herbicides,but the response to different herbicides was different,so the resistance to different herbicides was different.In addition,the activity of CYP450 in Jingu 21 could be maintained at a high level with high concentration monosulfuron stress,which enhanced its ability of metabolic detoxification to herbicides,which was one of the reasons that Jingu 21 showed strong resistance to monosulfuron.