石油污染胁迫下植株根区土壤微生物多样性分析

Effect of oil pollution stress on diversity of microbes in plant root soil

【目的】研究在不同石油污染胁迫水平下,适合陕西延安气候与土壤条件的4种耐性植株根区土壤微生物多样性的变化。【方法】采用室外盆栽模拟法,在含0,5,10,15和20g/kg石油的土壤中栽植油松、沙棘、刺槐、紫穗槐4种植株,待苗木生长6个月后采集其根区周围土壤,采用微生物平板培养法、酸碱滴定法及Biolog微平板法,从微生物区系、呼吸强度及功能多样性角度,对不同石油污染胁迫水平下植株根区土壤的微生物多样性进行分析。【结果】栽植4种植株均能促进根区土壤微生物的生长,增加根区土壤微生物多样性;在高水平石油污染胁迫下,4种植株对根区土壤微生物的多样性具有保护作用,其中刺槐植株表现最为明显;5~10g/kg石油污染胁迫水平能刺激植株根区土壤微生物的生长,促进植株根区土壤微生物对碳源的利用;15~20g/kg石油污染胁迫水平对部分土壤微生物具有毒害作用,对根区土壤微生物的碳源利用有抑制作用,其中20g/kg石油污染胁迫水平的毒害及抑制作用最强。主成分分析结果显示,第1主成分将10g/kg石油污染胁迫水平与0,20g/kg石油污染胁迫水平的土壤微生物功能多样性明显区分开来,第2主成分将0g/kg石油污染胁迫水平与其他石油污染胁迫水平的土壤微生物功能多样性区分开来,其中影响第1主成分的碳源主要为多聚物类和氨基酸类,影响第2主成分的碳源主要为碳水化合物类。【结论】4种植株均能有效提高石油污染胁迫下根区土壤微生物的多样性;5~10g/kg石油污染胁迫水平能提高土壤微生物多样性;15~20g/kg石油污染胁迫水平降低了土壤微生物多样性,对微生物生长具有毒害作用。

【Objective】The aim of the experiment was to understand the effect of oil pollution stress on diversity of microbes in root soil of four tolerant plants,which could adapt to the climate and soil conditions in Yan'an.【Method】Using outdoor potted method,four plants including Pinus tabulaeformis,Hippophae rhamnoides,Robinia pseudoacacia,and Amorpha fruticosa were planted in soil polluted by 0,5,10,15and20g/kg oil,respectively.After 6months,soil samples were taken from plant root zone to analyze the effect of oil pollution stress on diversity of microbes using microbial plate culture,breathing intensity assay and Biolog system methods.【Result】All of the four plants promoted the growth of root zone soil microbes and increased root zone soil microbial diversity.Under high oil pollution stress,plants protected the diversity of root zone soil microbes.Robinia pseudoacacia had the best performance.When the oil pollution stress was5―10g/kg,the growth of plant root zone soil microbes was stimulated by promoting the utilization ofcarbon source.When the oil pollution stress was 15―20g/kg,the growth of microbes was depressed since the carbon utilization was inhibited and 20g/kg level had the strongest adverse effects.According to principal component analysis,the first principal component(PC1)distinguished the effect of 10g/kg oil pollution stress from 0and 20g/kg levels.The second principal component(PC2)distinguished the effect of 0g/kg oil pollution stress from other levels.The carbon sources affecting PC1 were polymers and amino acids while those affecting PC2 were carbohydrates.【Conclusion】All four tested plants could effectively increase the diversity of root zone soil microbes.5―10g/kg oil pollution stress promoted soil microbial diversity while 15―20g/kg oil pollution stress reduced soil microbial diversity.