土壤低含量铅时冬小麦幼苗根际微生物群落的变化

Changes of Microbial Communities in Rhizosphere of Winter Wheat Seedlings under Low Lead Content

摘要:

采用土壤盆栽试验法研究了土壤低含量铅(Pb)(质量比小于300 mg/kg干土)对冬小麦幼苗根际微生物的影响特征。与对照相比，幼苗生长3周和7周时，低含量Pb对细菌数量的平均抑制率分别为16.25%和8.62% (p<0.01)；幼苗生长3周、7周和12周时，低含量Pb对真菌数量的平均抑制率分别为34.08%、39.89%和17.49% (p<0.01)；7周和12周时，与对照相比，低含量Pb极显著(p<0.01)抑制放线菌数量增殖。幼苗生长3周时，真菌数量与Pb含量极显著(p<0.01)相关；7周时，真菌、放线菌和微生物总数与Pb含量显著(p<0.05)相关。低含量Pb处理下，根际真菌/细菌比值较对照显著降低，微生物代谢功能多样性变化显著。研究结果表明：土壤低含量Pb对冬小麦幼苗根际土壤微生物数量及微生物群落结构特征影响显著。

关键词:冬小麦;低含量铅;根际土壤;微生物;微生物代谢功能多样性

Abstract:

Pot experiments were conducted to investigate the effect of low lead content (<300mg/kg dry soil) on winter wheat seedlings rhizosphere microorganisms. Compared to the control, the number of bacterial decreased significantly (p<0.01) by 16.25% at the third week and by 8.62% at the seventh week, and the number of fungi in low lead content decreased significantly (p<0.01) by an average of 34.08%, 39.89% and 17.49% at the third week, seventh week, and twelfth weeks, respectively. The actinomyces amount in low lead content decreased significantly (p<0.01) at the seventh and twelfth weeks. The correlation between the number of fungi and lead content was significant (p<0.01) at the third week and the number of actinomyces, the fungi and the total microbial had significant (p<0.05) correlation to the lead content at the seventh week. In the three growth stages, fungal/bacterial population ratio decreased evidently and the microbial functional diversity changed evidently in low lead content. In conclusion, soil microbial population and community in the rhizosphere of winter wheat seedlings were affected significantly by low lead content.

Key words:Winter wheat;Low lead content;Rhizosphere soil;Microorganism;Microbial functional diversity