摘要
通过不同铅浓度下小白菜根际土壤微生物数量、硝化和反硝化速率及呼吸速率等特征的研究,揭示铅污染对植物根际微生态系统生态安全性的影响。结果表明,随着铅浓度的增加,细菌、真菌和放线菌数量均呈现先升后降的变化趋势,峰值所对应的铅浓度分别为300、300和600 mg/kg,3种微生物的耐铅能力为真菌>放线菌>细菌。土壤硝化和反硝化细菌数、硝化和反硝化速率及呼吸速率也随着铅浓度的增加先升后降,各指标峰值所对应的铅浓度均为300 mg/kg;硝化速率与硝化细菌数、反硝化速率与反硝化细菌数及土壤呼吸速率与微生物总数决定系数分别为0.684 7、0.851 1和0.684 3,均显著正相关。研究发现,当土壤铅浓度达到或超过1 200 mg/kg时,小白菜根际微生态系统出现显著的微生物群落结构和功能退化。
By studying the characteristics of microbial number,nitrification and denitrification rates and respiration rate of rhizosphere soil of Brassica chinensis L. grown under the different concentration of lead（ Pb） environments,the effect of lead on the ecological safety of plant rhizosphere micro-ecosystem was revealed. The results showed that the all numbers of bacteria,fungi and actinomycetes first increased and then decreased with increase of Pb concentration,and the peak value occurred in the environment with soil Pb concentration of 300 mg / kg,300 mg / kg and 600 mg / kg,respectively. The Pb tolerance of microbe was fungi actinomycetes bacteria under the Pb stress environments. The all numbers of nitrifying and denitrifying bacteria in the rhizosphere,soil nitrification and denitrification rate,and soil respiration rate also first increased and then decreased with increase of Pb concentration,and peak values of all above parameters occurred in the environment with soil Pb concentration of 300 mg / kg. Nitrification rate and number of nitrifying（ R2= 0. 684 7）,denitrification rate and number of denitrifying bacteria（ R2= 0. 851 1）,and respiration rate and the total number of microbe（ R2= 0. 684 3） were all correlated significantly and positively. In conclusion,only when the soil Pb concentrations reaches or exceeds1 200 mg / kg,significant microbial community structural and functional degradation of B. Chinensis rhizosphere micro-ecosystem will occur.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2014年第12期203-208,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
'十二五'国家科技支撑计划资助项目(2014BAD08B04)
江苏高校优势学科建设工程资助项目(苏政办发[2014]37号)
关键词
小白菜
微生物
铅胁迫
硝化
反硝化
呼吸速率
Brassica chinensis Microbe Lead stress Nitrification Denitrification Respiration
