环丙沙星高低累积菜心根际土壤酶活性和微生物学特性差异研究

Variations in rhizosphere enzymatic activities and microbiological characteristics between high and low ciprofloxacin accumulation cultivars of Brassica campestris L.

为查明环丙沙星高、低累积菜心根际消除环丙沙星(CIP)高低差异的微生物学机理,通过室内土壤盆栽实验,研究了这两种菜心根际土壤中酶活性和微生物学特征差异。结果表明:种植高、低累积菜心均促进土壤CIP的消除,在高污染水平时,高累积菜心对土壤CIP的消除效果显著高于低累积菜心,其降解率分别为48.7%和39.4%(P<0.05);高累积菜心根际土壤的可培养细菌数量和细菌群落结构多样性与丰富度(尤其含CIP特异降解菌Beta proteobacteria的相对丰度),以及过氧化氢酶和脲酶活性均显著高于低累积菜心。研究结果初步揭示了高累积菜心根际去除CIP能力更强且体内吸收累积CIP更多这一初步机理。

The rhizosphere microecology plays a key role in uptake and accumulation of pollutants in plants. The variations in rhizosphere enzymatic activities and microbiological characteristics between high and low ciprofloxacin（CIP） accumulation cultivars of Brassica campestris L. were investigated using pot experiments to expound the microbiological mechanism of variations in removal of CIP in the rhizosphere of the two cultivars. Results showed that cultivation of both the cultivars significantly enhanced the degradation of CIP in soil. At high CIP level, the removal efficiency of CIP in the rhizosphere of the high accumulator（48.7%）was significantly higher than that of the low accumulator（39.4%）（P〈0.05）. The amount of cultivable bacteria; the richness and evenness of the soil bacterial community, especially the Beta proteobacteria-containing CIP-degrading bacteria; and the activities of catalase and urease in the rhizosphere of the high accumulator were significantly higher than those of the low accumulator. These results preliminarily revealed the mechanism of higher bioconcentration and removal of CIP in the rhizosphere of the high CIP accumulation cultivar.