植物根际促生菌对高原早熟禾根际土壤氮素及固氮微生物的影响

Effects of plant growth-promoting rhizobacteria on nitrogen and nitrogen-fixing microorganisms in rhi⁃ zosphere soil of Poa alpigena

摘要:

为研究植物根际促生菌对土壤氮素和固氮微生物含量的影响，通过 5 株优良植物根际促生菌接种高原早熟禾，研究它们对根际土壤全氮、速效氮含量，土壤脲酶活性、土壤固氮菌、土壤固氮菌 nifH 基因相对丰度的影响。结果发现：植物根际促生菌对土壤氮素和固氮微生物含量有明显的提高作用，不同菌株的作用效果不同。使用促生菌后，土壤全氮含量提高了 8. 3%~41. 67%，土壤速效氮的含量提高了 3. 98%~45. 64%，土壤微生物量氮含量提高了 21. 27%~34. 28%，土壤脲酶活性提高了 20. 0%~28. 89%，土壤好气性自生固氮菌含量提高了 37. 98%~64. 52%，土壤嫌气性自生固氮菌含量提高了 5. 56%~24. 6%，土壤固氮菌 nifH 基因的相对丰度提高了 4. 64%~18. 5%。说明植物根际促生菌能够促进土壤氮代谢，提高土壤固氮微生物的含量，对于土壤健康具有重要的作用。

Abstract:

To investigate the effects of plant growth-promoting rhizobacteria(PGPR)on the contents of soil ni- trogen and nitrogen-fixing microorganisms，five excellent PGPR strains which were obtained in previous study were explored on their effects on soil total nitrogen，available nitrogen content，soil urease activity，soil nitrogen-fixing bac- teria and soil nifH gene. The results showed that PGPR could significantly increase the contents of soil nitrogen and nitrogen-fixing microorganisms，and the degrees of effect varied among the strains. After PGPR application，the soil total nitrogen increased by 8. 3%~41. 67%，the soil available nitrogen increased by 3. 98%~45. 64%，the soil micro- bial biomass nitrogen increased by 21. 27%~34. 28%，the soil urease activity increased by 20. 0%~28. 89%，the soil aerobic autotrophic nitrogen-fixing bacteria increased by 37. 98%~64. 52%，the content of soil anaerobic autotrophic nitrogen-fixing bacteria increased by 5. 56%~24. 6%，and the relative abundance of nifH gene in soil nitrogen-fixing bacteria increased by 4. 64%~18. 5%. In this study，the effects of PGPR on soil were investigated from the perspec- tives of soil nitrogen and nitrogen-fixing microorganisms. The results suggested that PGPR could play an important role in soil health through promoting soil nitrogen metabolism，improve the soil nitrogen-fixing microorganisms.