黄河三角洲刺槐白蜡混交对土壤细菌群落结构及多样性的影响

为探讨黄河三角洲刺槐白蜡混交对土壤细菌群落结构及多样性的影响,通过高通量测序技术分析比较了刺槐白蜡混交林及刺槐纯林、白蜡纯林土壤细菌群落结构及多样性。结果表明:(1)混交林与两种纯林土壤细菌群落共36门。酸杆菌门、变形菌门、放线菌门(相对丰度大于10%)为刺槐白蜡混交林与两种纯林土壤中共有的优势菌群;硝化螺旋菌门为刺槐纯林土壤中的优势菌群。不同人工林土壤中各门细菌相对丰度差异显著。(2)混交改变了土壤细菌群落结构,提高了细菌多样性。刺槐白蜡混交林土壤细菌物种数、Chao1指数、Shannon指数分别为1934.5、2629.1、9.1,显著高于两种纯林。(3)相关性分析表明,土壤含水量与放线菌门细菌呈显著正相关;pH与芽单胞菌门细菌呈极显著正相关,与酸杆菌门细菌呈显著负相关。细菌多样性与土壤含水量呈显著正相关,与速效钾、有机质含量呈显著负相关。研究表明,刺槐白蜡混交林土壤细菌群落结构与两种纯林之间有一定差异,多样性差异显著,刺槐白蜡混交改变细菌群落结构,提高细菌多样性。

Effects of a mixed plantation of Robinia pseudoacacia and Fraxinus velutina on soil bacterial structure and diversity in the Yellow River Delta

In order to investigate the effects of a mixed plantation of Robinia pseudoacacia and Fraxinus velutina on soil bacterial structure and diversity in the Yellow River Delta, the soil bacterial community structure and diversity in pure and mixed plantations of Robinia pseudoacacia and Fraxinus velutina were analyzed using high-throughput sequencing technology. The results showed the following:there were 36 phyla of bacterial communities in pure and mixed plantations of R. pseudoacacia and F. velutina. Acidobacteria, Proteobacteria, and Actinobacteria were the dominant bacterial taxa for the two pure forests and the mixed forest, each with a relative abundance of more than 10%, and Nitrospirae was the dominant bacterial taxon for R. pseudoacacia.The relative abundance of bacteria in the mixed plantation of R. pseudoacacia and F. velutina were significantly different from those in the pure plantations. Among these three plantation types, observed species (1934.5), Chao 1 index (2629.1), and Shannon index (9.1) were highest in the mixed forests. There was a significant positive correlations (0.995^*) between soil water content and the quantity of Actinobacteria. Soil pH had a very significant positive correlation (0.999^**) with the quantity of Gemmatimonadetes, and a very significant negative correlation (-0.909) with the quantity of Acidobacteria. Soil bacterial diversity showed a very significant positive correlation with soil water content, and a very significant negative correlation with soil available K. The results showed differences in structure and diversity of the soil bacterial community between the pure and mixed stands of R. pseudoacacia and F. velutina. Having changed the structure of bacterial community and increased bacterial diversity, the mixed plantation of R.pseudoacacia and F. velutina had differences in structure and diversity of the soil bacterial community from the two pure forests.