Study On The Mitigation Effect Of Brassinolide Of Benzazole · Dimethyl Sodium On Broomcorn Millet Herbicide

Broomcorn millet is one of the main coarse grain crops in China.Weeds can reduce the production of broomcorn millet.The use of herbicides can improve the efficiency of weeding in millet fields,and at the same time,it will also have certain phytotoxic effects on millet.The phytotoxicity of herbicide was mitigated by Brassinolide（BR）,In order to explore the feasibility of Brassinolide as a safener for Benzazole·dimethyl sodium,this study through field experiments combined with laboratory analysis measured the effects of Brassinolide on phytotoxicity,control effects of weeds,agronomic characters and yield,photosynthetic fluorescence characteristics,physiological metabolism and soil enzyme activity of millet under Benzazole·dimethyl sodium stress were explored the physiological mechanism of phytotoxicity and its impact on soil environment.The main research results are as follows:（1）Single application of different doses of Benzazole·dimethyl sodium produced phytotoxicity to the millet,and it increased with the dose.Spraying different concentrations of Brassinolide can effectively alleviate the damage of Benzazole·dimethyl sodium and significantly reduced the phytotoxicity index of millet.Compared with the control of single application of Benzoyl·dimethylsodium,the different concentrations of Brassinolide weakened the biological activity of Benzoyl·dimethylsodium in a certain extent,and slightly reduced the control effect of weeds.（2）Compared with the control of single application of Benzazole·dimethyl sodium,different concentrations of Brassinolide significantly increased the ear length and main ear weight of millet.After spraying medium and high doses of Benzazole·dimethyl sodium,respectively,spraying medium and high concentrations of Brassinolide could significantly increase the leaf area and abovegroun dry weight of millet.Compared with the control of single application of Benzazole·dimethyl sodium,different concentrations of Brassinolide significantly increased seed yield of millet.The maximum yield was gained in the treatments of medium-dose Benzoxazole·dimethyl+medium-concentration Brassinolide and high-dose Benzoxazole·dimethyl+high-concentration Brassinolide with19.7%and18.3%than the herbicide application only,respectively.（3）Compared with the control of single application of Benzazole·dimethyl sodium,different concentrations of Brassinolide significantly increased the activity levels of POD,SOD,CAT,GST,as well as GSH contents,but significantly decreased MDA content in flag leaf.The medium-dose Benzazole·dimethyl sodium+medium-concentration Brassinolide and high-dose Benzazole·dimethyl sodium+high-concentration Brassinolide showed the best effect in improving the activity levels of POD,SOD,CAT,GST,as well as GSH contents,and decresing MDA content.（4）Compared with the control of single application of Benzazole·dimethyl sodium,spraying medium and high doses of Benzazole·dimethyl sodium followed by spraying medium and high concentrations of Brassinolide respectively could promote the chlorophyll content,Gs,Pn,Tr,Fv/Fm,q L andΦ_PSII,but significantly decreased Ci and NPQ of broomcorn millet flag leaf,effectively relieved the restriction of Benzazole·dimethyl sodium on the non-stomatal factors of the flag leaf,reduced the heat dissipation of flag leaf and enhanced the photosynthesis of broomcorn millet flag leaves.（5）Compared with the control of single application of Benzazole·dimethyl sodium,spraying medium and high doses of Benzazole·dimethyl sodium followed by spraying medium and high concentrations of Brassinolide respectively could significantly increased the activity levels of PEPC,NAD-MDH,PPDK,while reducing NAD-ME and Rubisco enzyme activities,effectively relieved the inhibitory effect of Benzazole·dimethyl sodium on the carbon assimilation of chytrid leaves,and restored the carbon assimilation enzyme activity to the normal level.（6）Compared with the control of single application of Benzazole·dimethyl sodium,spraying Brassinolide can effectively alleviate the inhibitory effect of Benzoxazole·dimethylsodium on the activity of soil enzymes in the rhizosphere soil of broomcorn millet.It could significantly improved the activity levels of catalase and alkaline phosphatase,and alleviated the toxic effects of herbicide Benzazole·dimethyl sodium on the soil ecological environment.The medium-dose Benzazole·dimethyl sodium+medium-concentration Brassinolide and the high-dose Benzazole·dimethyl sodium+high-concentration Brassinolide showed the best effect,alleviating soil enzyme activity levels of the inhibition of Benzazole·dimethyl sodium.Comprehensive analysis showed that t he maximum effect on the phytotoxicity of Benzazole·dimethyl sodium was alleviation in the treatments of 0.6 kg·hm^-2of Benzazole·dimethyl sodium+0.08 mg·L^-1 of Brassinolide,0.9 kg·hm^-2 of Benzazole·dimethyl sodium+0.10 mg·L^-1 Brassinolide,and at the same time improve the activity of key enzymes in carbon metabolism and photosynthetic fluorescence properties,enhance the production capacity of aboveground photosynthetic substances and increase the yield of broomcorn millet.