再生水中的Pb对萝卜根际土壤微生物群落结构的影响研究

Impacts of Lead in the Reclaimed Water on the Microbial Community Structures in the Radish Rhizosphere

采用盆栽方法研究再生水、再生水+Pb、清水+Pb处理浇灌萝卜,以清水浇灌为对照对萝卜根际土壤微生物群落的影响进行研究。结果表明:(1)土壤总PLFA含量及各菌群生物量从大到小依次为:再生水>再生水+Pb>清水>清水+Pb。再生水灌溉有利于萝卜根际微生物各类群数量的增加,丰富微生物多样性。用含铅的溶液(再生水+Pb、清水+Pb)浇灌萝卜,可抑制土壤微生物各类群的数量,G-受到的抑制尤为明显。(2)主成分分析表明,再生水灌溉与对照相比,土壤微生物群落结构差异最大。(3)土壤微生物各类群与土壤速效钾、硝酸盐氮含量呈极显著正相关(P<0.01),真菌、放线菌与土壤有机质含量,G^+、G^-菌与p H均呈极显著正相关(P<0.01)。G^+、G^-与萝卜地下鲜重均呈极显著负相关(P<0.01),土壤微生物各类群与地上部分硝酸盐含量、与根冠比呈极显著正相关(P<0.01)。

In this paper, by application of pot experiments, impacts of reclaimed water, reclaimed water plus Pb, tap water plus Pb, and tap water alone as a control on microbial community structures in the radish rhizosphere were studied in the greenhouse. The results showed that the impacts on the total soil phospholipid fatty acids（PLFAs） and each microbial community biomass were shown in the order of reclaimed waterreclaimed water plus Pbtap watertap water plus Pb. Irrigation with reclaimed water was favorable for increasing the quantity of different soil microbial groups and enriching the microbial diversity. Irrigation with reclaimed water plus Pb and tap water plus Pb inhibited the quantity of the soil microbial groups, especially for gram-negative bacteria. Principal component analysis indicated that the effect of reclaimed water on the microbial structures had the biggest difference from that of the tap water. Various soil microbial groups were strongly positively correlated with the contents of available potassium and nitrates（P〈0.01）. Fungi and actinomycetes were significantly positively correlated with the content of soil organic matter（P〈0.01）. Gram-positive and gramnegative bacteria showed a significant positive correlation with p H（P〈0.01）. Gram-positive and gram-negative bacteria were significantly negatively correlated with the fresh weight of the radish underground part. Different soil microbial groups were strongly positively correlated with the contents of nitrates in the radish leaves as well as the root-shoot ratio（P〈0.01）.