Study On Effects Of Safety Agents And Herbicides On The Physiological Metabolism Of Broomcorn Millet

As one of the main coarse grain crops in China,broomcorn millet has high nutritional and health value,and is also an important feed source.It is an important stable crop in arid and semi-arid areas.In the production,different degrees of grass damage will occur in millet fields,and the use of herbicides will cause mild or heavy effects on millet,which will affect the yield and quality of millet.The research and application of safety agents is of great significance to reduce or solve the negative effects of herbicides on crop growth.In this study,different kinds of safety agents(Brassinolide,Gibberellin,Naian)and combined with two kinds of herbicides(Guyou,Benzazole·dimethyl sodium)were sprayed to explore the effects of safety agents on herbicide mitigation effect and physiological metabolism.The main research results are as follows:(1)The combination of Guyou and Benzazole·dimethyl sodium with Brassinolide,Gibberellin,and Naian can effectively alleviate the drug injury and significantly reduce the drug injury index.The combination of Guyou with low,medium and high concentrations of Gibberellin,and the combination of Benzazole·dimethyl sodium with low,medium and high concentrations of Brassinolide also significantly reduced the pesticide index of broomcorn millet plants.(2)Compared with the herbicide spraying alone,Guyou and Benzazole·dimethyl sodium combined with three safety agents had little effect on weed control efficacy in millet fields,and the weed control efficacy could all reach more than 90%.The combination of Guyou with low,medium and high concentrations of Gibberellin and the combination of Benzazole·dimethyl sodium with low,medium and high concentrations of Brassinolide had almost no effect on the weed control efficiency,and the weed control efficiency was more than 84%,all of which achieved good weed control effect.(3)Compared with the herbicide spraying alone,the plant height and main panicle weight were increased in different degrees after the combined spraying of Guyou and Benzazole·dimethyl sodium with Brassinolide,Gibberellin and Naian.The plant height of millet was significantly increased by the combination of glutamate and low concentration Gibberellin,while the plant height,stem diameter,panicle length and main panicle weight of millet were increased by the combination of Benzazole·dimethyl sodium with low,medium and high concentration Brassinolide.The dry matter weight of millet leaves,stems,sheaths and panicles were increased by the combination of three safety agents and two herbicides respectively.Compared with the herbicide spraying alone,the combination of Guyou with low and medium concentrations of Gibberellin increased the stomatal conductance and net photosynthetic rate of flag leaves of millet at grain filling stage,and the combination of Benzazole·dimethyl sodium with low,medium and high concentrations of Brassinolide increased the stomatal conductance,net photosynthetic rate and transpiration rate of flag leaves of millet.(4)The use of Guyou and Benzazole·dimethyl sodium significantly reduced the yield of broomcorn millet compared with the control of artificial herbicide.When combined with the three safety agents,they had a significant effect of increasing the yield.The combination of the pre-seedling herbicide Guyou and the safety agent Gibberellin had the best yield increase,which was 33.41%higher than that of single application of herbicide Guyou.The combination of Benzazole·dimethyl sodium and safety agent Brassinolide produced the best yield increase,which was 19.88%higher than that of single application of herbicide Benzazole·dimethyl sodium.The combined spraying of Guyou with three concentrations of Gibberellin and the combined spraying of Benzazole·dimethyl sodium with three concentrations of Brassinolide also increased the yield to different degrees.Especially in the years with more rain,the effect of weed control and yield increase was more obvious,the combination of Guyou+medium concentration Gibberellin and Benzazole·dimethyl sodium+low concentration Brassinolide had the best yield increase,which was 16.88%and 15.95%compared with the the herbicide spraying alone.(5)The combination of Guyou and Benzazole·dimethyl sodium with Gibberellin,Brassinolide and Naian can significantly increase the activities of SOD and POD,and reduce the content of MDA in broomcorn millet.The activities of SOD and POD of broomcorn millet were increased by the combination of Guyou+medium concentration Gibberellin and Benzazole·dimethyl sodium+low concentration Brassinolide.At the early stage of grain filling,SOD activity increased by 20.2%and 34.2%,and POD activity increased by 19.4%and 33.6%,respectively,compared with herbicide application.The GSH content and GST activity of broomcorn millet were significantly increased by the combination of Guyou and Benzazole·dimethyl sodium with the three safety agents,respectively.The GSH content and GST activity of broomcorn millet were significantly increased by the combination of Guyou+medium concentration Gibberellin and Benzazole·dimethyl sodium+low concentration Brassinolide.Compared with herbicide application,the content of GSH at the early stage of grain filling was increased by 18.7%and 19.0%,respectively,and the activity of GST at the heading stage was increased by 20.8%and16.5%,respectively.In conclusion,the application of Guyou(2.4 kg/hm~2)+Gibberellin(300 m L/hm~2)after sowing and before the emergence of seedlings or the application of Benzazole·dimethyl sodium(0.6 kg/hm~2)+Brassinolide(210 m L/hm~2)around the four leaf stage had the best phytotoxicity-relieving effect on broomcorn millet.It can effectively enhance the activity of active oxygen metabolism enzymes in the functional leaves of broomcorn millet,and promote the combination of glutathione and exogenous toxins in herbicide by increasing the content of GSH and the activity of GST,and alleviate the herbicide damage,increase the yield of broomcorn millet.