| 香豆素对苜蓿生长的自毒效应分析及其降解菌筛选与鉴定 |
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| 引用本文：赵廷伟， 季 彬， 彭轶楠， 宋 婕， 叶 泽， 杨建军，王治业.香豆素对苜蓿生长的自毒效应分析及其降解菌筛选与鉴定[J].西北农业学报,2026,(3):494~502 |
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| 基金项目:甘肃省科学院青年科技创新基金(2023QN-01)。 |
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| 中文摘要:为缓解由于香豆素等自毒物质所引起的苜蓿连作障碍问题，通过高效液相色谱（HPLC）法对异龄苜蓿植株及根际土壤中香豆素含量进行检测和对其自毒效应进行验证分析；同时以香豆素作为唯一碳源对苜蓿根际土壤中香豆素降解菌株进行分离、筛选和16S rDNA基因序列鉴定。利用不同选择性培养基对所筛菌株的相关特性进一步研究分析。结果显示，随着生长年限的增加，苜蓿植株及根际土壤中香豆素浓度呈显著上升趋势，最高分别可达227.31 μg/g和3.21 μg/g。且当香豆素浓度在0~500 μg/mL不断升高时，会严重抑制其发芽势和胚根、胚芽的生长。当其浓度达到1 μg/mL时，胚根、胚芽伸长长度分别减少36.49%和7.91% ；浓度超过10 μg/mL时，种子发芽势降低为0，均达到显著水平。通过筛选获得1株高效香豆素降解菌株，经鉴定为恶臭假单胞菌（Pseudomonas putida），其最大降解率接近100%。功能性分析表明，该菌株同时具备溶磷、解钾、固氮及分泌ACC脱氨酶的能力。通过此研究发现苜蓿连作会导致土壤中香豆素含量不断积累，并严重影响苜蓿种子的发芽和幼苗的生长。恶臭假单胞杆菌具有较强的香豆素降解能力和环境适应能力，这为后期微生物防治自毒物质提供了菌种资源和理论基础。 |
| 中文关键词:苜蓿 自毒作用 香豆素 降解菌 恶臭假单胞杆菌 |
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| Analysis of Autotoxic Effects of Coumarin on Alfalfa Growth and Identification of Coumarin-Degrading Bacteria |
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| Abstract:To address the continuous cropping obstacles in alfalfa caused by autotoxic compounds such as coumarin,the coumarin content in alfalfa plants of different ages and their rhizosphere soil was measured using high performance liquid chromatography (HPLC) and their autotoxic effect was evaluated.Coumarin was also used as the sole carbon source to isolate coumarin-degrading strains from the rhizosphere soil,which were subsequently identified based on their 16S rDNA gene sequence.The physiological and biochemical characteristics of the isolated strains were further analyzed using different selective media.The results showed that with the increase of growth years,the coumarin concentration in both alfalfa plants and rhizosphere soil significantly increased,peaking at 227.31 μg/g and 3.21 μg/g,respectively.Moreover,increasing coumarin concentrations from 0 to 500 μg/mL significantly inhibited seed germination potential as well as radicle and hypocotyl growth.At 1 μg/mL,the elongation of radicles and hypocotyls decreased by 36.49% and 7.91%,respectively.When the concentration exceeded 10 μg/mL,seed germination potential dropped to zero,with all changes being statistically significant.Through screening,one highly efficient coumarin-degrading strain was obtained and identified as Pseudomonas putida,with a maximum degradation rate approaching 100%.Functional analysis indicated that this strain possessed multiple plant growth-promoting traits,including phosphorus solubilization,potassium release,nitrogen fixation,and ACC deaminase secretion.This study demonstrated that continuous alfalfa cropping leads to the gradual accumulation of coumarin in the soil,which severely impairs seed germination and seedling growth.Pseudomonas putida has strong coumarin degradation capacity and environmental adaptability,providing strain resources and theoretical basis for the microbial control of allelochemicals in the future. |
| keywords:Alfalfa Autotoxicity Coumarin Coumarin-degrading bacteria Pseudomonas putida |
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