芽孢杆菌复合菌群的构建及其对野燕麦除草活性研究

Construction of Bacillus compound flora and its herbicidal activity against Avena fatua L.

【目的】构建芽孢杆菌复合菌群,优化菌群组合并研究其杀草谱、作物安全性及对野燕麦的除草活性,为开发新型生物除草菌剂提供新思路和理论依据。【方法】以课题组前期筛选到的芽孢杆菌D30202、JZ1-1-9、JZ2-4-15和JZ2-2-1为材料,采用皿内对峙试验测定菌株间的相容性,并结合分光光度法测定菌株生长曲线,确定构建复合菌群的菌株和组合时期;通过种子萌发袋法测定复合菌群对杂草种子萌发的根长、芽长抑制率和干重、鲜重抑制率以优化菌株组合类型;采用盆栽试验对最优组合菌群进行杀草谱及作物安全性评价,测定作物叶片丙二醛(MDA)含量,超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)3种防御酶活性作为对野燕麦除草活性反应的指标。【结果】待选菌株两两之间无拮抗关系且生长周期一致,由菌株D30202、JZ1-1-9和JZ2-4-15构建的复合菌群2-9-15为最优组合。菌群2-9-15抑制野燕麦种子萌发和幼苗生长的综合效果最明显,根长和芽长抑制率分别为39.17%和73.49%,幼苗鲜重和干重抑制率分别为25.11%和21.26%。盆栽试验结果显示,菌群2-9-15的除草广谱性及作物安全性均优于精喹禾灵,除禾本科作物青稞外,菌群2-9-15对玉米、藜麦、小麦、蚕豆、豌豆和马铃薯等当地主栽作物安全性高。3叶期野燕麦分别经精喹禾灵和菌群2-9-15喷施处理3 d后,叶片MDA含量、SOD和CAT活性下降趋势一致。【结论】复合菌群2-9-15具有较高的抑草活性及广谱性,具有开发为防治野燕麦等禾本科杂草生防制剂的潜力。

【Objective】To construct the Bacillus compound flora,optimize the flora combination and study its herbicidal spectrum,crop safety and herbicidal activity against Avena fatua L.,providing new ideas and theoretical basis for the development of new biological herbicides.【Method】The Bacillus strains D30202,JZ1-1-9,JZ2-4-15 and JZ2-2-1 screened by the research group in the early stage were used as materials.The compatibility between the strains was determined by the in-dish confrontation test,and the growth curve of the strains was determined by spectrophotometry to determine the strains and combination periods for constructing the composite flora.The root length,bud length inhibition rate,dry weight and fresh weight inhibition rate of the compound flora on weed seed germination were determined by seed germination bag method to optimize the strain combination type.The pot experiment was used to evaluate the weed control spectrum and crop safety of the optimal combination flora.The malondialdehyde(MDA)content of crop leaves and the activities of three defense enzymes,superoxide dismutase(SOD),catalase(CAT)and peroxidase(POD),were measured as indicators of the response to the weed control activity of A.fatua L.【Result】There was no antagonistic relationship be-tween each two strains to be selected and the growth cycle was the same,and the compound flora 2-9-15 constructed by strains D30202,JZ1-1-9 and JZ2-4-15 was the optimal combination.The combined effect of the compound flora on seed germination and seedling growth of A.fatua L.was the most significant.The inhibition rates of root and shoot growth were 39.17%and 73.49%,respectively,and the inhibition rates of fresh and dry weight of seedlings were 25.11%and 21.26%.The herbicidal broad-spectrum and crop safety of the compound flora 2-9-15 in the pot experiment were higher than that of quizalofop-p-ethyl.Except for gramineous crop Hordeum vulgare,it had high safety to local crops such as Zea mays L.,Chenopodium quinoa Willd.,Trticum aestivum L.,Vicia faba L.,Pisum sativum L.and Solanum tuberosum L.After three-leaf stage A.fatua L.was sprayed with quizalofop-p-ethyl and compound flora for 3 d,the MDA content,SOD and CAT activity in leaves decreased and the decreasing trend was consistent.【Conclusion】The compound flora 2-9-15 has high herb-inhibitory activity and broad-spectrum,and has the potential to be developed as a biocontrol agent for the control of gramineous weeds such as A.fatua L.