磺胺嘧啶胁迫下作物根际微生物群落结构响应

Responseof microbial community structure of crops under the pollution of sulphadiazine on the rhizosphere microinterface

为了研究在磺胺类兽药胁迫下,两种作物在不同生长期根际微生物群落结构的响应,采用室内根际箱培养实验,测定玉米、小麦根际微界面土壤磷脂脂肪酸的量,研究在磺胺嘧啶(SD)胁迫下,不同作物根际土壤微界面微生物群落结构的空间变化.结果表明,SD对根际微生物活性的有抑制作用,且强度随浓度增加而增强.同一浓度SD作用下,根际微界面微生物生物量不同,在实验中,根际3mm和根室的微生物生物量最大,且二者之间差异不显著.不同微生物对根际效应敏感程度不同,细菌、革兰氏阳性菌、革兰氏阴性菌、蓝细菌和硫酸盐还原菌根际效应明显.在SD胁迫下,根际不同微界面土壤微生物群落结构变化明显.细菌、G+、G-、放线菌的生物量,随SD浓度升高而下降,主要表现为抑制效应,而对真菌生物量则表现为激活效应,生物量增加.小麦根际土壤真菌:细菌(F/B)随SD浓度的升高,比值增大,在高浓度(5mg/kg)胁迫下,F/B比值最大(0.74),与对照差异显著(P<0.05),说明土壤污染修复能力增强,而sat/mono比值在高浓度SD胁迫下降低,说明微生物群落结构向有利于SD降解的方向转化.根际效应有助于SD的降解,在1mg/kg SD作用下,小麦根际土壤降解率为7.01%,而非根际土壤降解率仅为2.49%,不同作物表现出的根际效应强弱不同,玉米根际效应强于小麦.

In order to study the response of two crops to the microbial community structure of rhizosphere in different growth periods under sulfa veterinary drug stress.The amount of phospholipid fatty acids in soils at different micro-interfaces in rhizosphere was determined by rhizobox training experiments.The changes of microbial community structure in different spatial micro-interfaces of domesticated maize and wheat rhizosphere soil under sulfadiazine stress were studied.The results showed that the high concentration of SD had an inhibitory effect on rhizosphere microbial activity,and microbial biomass at different micro-interfaces in rhizosphere was different.The microbial biomass of the rhizosphere 3mm and root chamber was the largest at the micro-interface of the rhizosphere,and the difference between the two was not significant.Different microorganisms had different sensitivity to rhizosphere effects,and rhizosphere effects of bacteria,Gram-positive bacteria,Gram-negative bacteria,cyanobacteria and sulfate-reducing bacteria were obvious.Under the action of SD stress and root exudates,the microbial community structure of rhizosphere soil changed significantly at different micro-interfaces.In the rhizosphere soil of wheat,the ratio of F/B increased with the increase of SD concentration in soil.Under the high concentration(5mg/kg),the F/B ratio was the largest(0.74),which was significantly different from the control(P<0.05),indicating that the soil pollution remediation ability was enhanced,the sat/mono ratio was decreased at high concentration,and the microbial community structure was transformed in the direction favorable for SD degradation.The rhizosphere effect was beneficial to SD degradation.Under the action of 1mg/kg SD,the degradation rate in wheat rhizosphere soil was 7.01%,while the degradation rate in non-rhizosphere soil was only 2.49%,and the rhizosphere effect of maize was stronger than wheat.