杨树根际土自毒物质的积累、毒害及生物修复

Accumulation,toxic properties and bioremediation of autotoxic substance in poplar rhizosphere soil

为研究杨树根际土壤中自毒物质的积累规律及其对杨树幼苗的毒害,分析多噬伯克霍尔德氏菌(Burkhold-eria multivorans)WS-FJ9对杨树自毒作用的生物修复特性,采用HPLC对1～5年生杨树根际土中的自毒物质进行测定;参照3年生杨树根际土壤中的自毒物质含量(设为X),在Hoagland营养液中设置4个自毒物质处理梯度(0.5X、1.0X、2.0X、3.0X),处理后第20天对水培苗进行施菌处理并继续培养至第30天分别采集根系样品进行生理生化指标的测定,同时测定了B.multivorans WS-FJ9降解自毒物质的速率。结果发现:不同林龄杨树根际土壤中均检测出对羟基苯甲酸、香草醛、阿魏酸、苯甲酸、肉桂酸等自毒物质;不同浓度的自毒物质均可抑制杨树水培幼苗根系SOD及POD的活性,增加根系细胞膜透性及细胞的MDA含量、降低根系活力;而B.mul-tivorans WS-FJ9处理能提高杨树水培幼苗根系SOD及POD的活性,降低根系细胞膜透性及MDA含量,增加根系活力;B.multivorans WS-FJ9对供试的5种自毒物质均具有较强的降解能力,其中对香草醛和对羟基苯甲酸的降解能力为最强,降解率分别达到98.73%和96.32%。

Accumulation law of autotoxic substance in poplar rhizosphere soil,toxic properties of autotoxic substance on poplar seedlings,bioremediation characteristic of Burkholderia multivorans WS-FJ9 on autotoxicity,and biodegradation characteristic on autotoxic substance were researched.Autotoxic substance of 1-5 growth years poplar rhizosphere soil was determined by HPLC.Hydroponic poplar seedlings were cultured in Hoagland nutrient solution added with different concentrations of autotoxic substance.Taked some of hydroponic poplar seedlings at the 20th d after treated with autotoxic substance to inoculate B.multivorans WS-FJ9 strain and continued to cultivate.Physiological and biochemical indexes were studied respectively at the 30th d after treated with autotoxic substance.Biodegradation rate of B.multivorans WS-FJ9 on autotoxic substance was determined.Autotoxic substance of phenolic acids are presented in different tree-age poplar rhizosphere soil.Different levels of autotoxic substance all can inhibit activities of SOD and POD,enhance membrane permeability and MDA content,and reduce roots activity of hydroponic poplar seedlings.On the other hand,the strain of B.multivorans WS-FJ9 can enhance activities of SOD and POD,reduce membrane permeability and MDA content,and enhance roots activity of hydroponic poplar seedlings.The strain of B.multivorans WS-FJ9 has strong biodegradation ability for the five autotoxic substances.And it has the strongest biodegradation ability for p-hydroxybenzoic acid and vanillin with biodegradation rates of 98.73% and 96.32%,respectively.