荒漠植物红砂根际土壤细菌群落特征及土壤酶活性研究

Characteristics of Bacterial Community and Soil Enzyme Activity in Rhizosphere Soil of Desert Plant Reaumuria Soongorica

为探究红砂(Reaumuria soongorica)根际土壤(Rhizosphere soil,RS)细菌群落特征,以民勤县青土湖红砂RS与非根际土壤(control CK)为研究对象。利用高通量测序技术分析其RS细菌群落,并通过相关性分析探究RS特性与根际细菌多样性之间的关系。结果显示:红砂RS与CK优势菌组成相似,但部分优势菌的相对丰度有显著差异(P<0.05)。其中,与CK_(3)相比,放线菌门(Actinobacteria)在RS_(3)中相对丰度减少41.82%。红砂RS细菌Alpha多样性指数显著高于对应CK(P<0.05)。土壤细菌Shannon指数在RS_(3)中提高最多,高于CK_(3)12.11%。红砂RS与CK的蔗糖酶、脲酶、碱性磷酸酶、过氧化氢酶活性均存在显著差异(P<0.05)。与CK_(2)相比,RS_(2)的脲酶活性增加88.61%;与CK_(3)相比,RS_(3)的碱性磷酸酶活性增加95.18%。红砂RS与CK全磷、速效磷存在显著差异(P<0.05)。RS 1中速效磷含量增加最多,高于CK 175.00%。综上,红砂RS细菌多样性及土壤酶活性显著高于CK,有助于改善荒漠土壤微环境。

The bacterial community structure of Reaumuria soongorica,a desert plant,in the rhizosphere soil(RS)was investigated by studying both the rhizosphere and bulk soil of this dominant plant species in Qingtuhu area of Minqin County.High-throughput sequencing technology was employed to analyze the bacterial community characteristics in the rhizosphere soil,and correlation analysis was performed to explore the relationship between enzyme activity,physicochemical properties of the rhizosphere soil,and rhizosphere bacterial diversity.The results revealed that Actinobacteria and Proteobacteria were dominant bacteria presenting in both types of rhizosphere and bulk soil.Although their composition was similar,there were differences observed in their relative abundance(P<0.05).Specifically,compared to control plots,RS_(3)plot exhibited a decrease in Actinobacteria's relative abundance by 41.82%,whereas an increase in Acidobacteria's relative abundance by 96.98%.Moreover,it was found that the bacterial Alpha diversity index of rhizosphere soil significantly exceeded bulk soil(P<0.05).In particular,Shannon index of rhizosphere soil bacteria increased by 12.11%for RS_(3)plot.Additionally,the activities of sucrase,urease,alkaline phosphatase and catalase differed significantly between rhizosphere soil and bulk soil(P<0.05),and these activities demonstrated positive correlations with rhizosphere bacterial diversity(P<0.05).Urease activity increased by 88.61%in RS_(2)plot compared to the control,while alkaline phosphatase activity increased by 95.18%in RS_(3)plot.Significant differences in total phosphorus and available phosphorus were observed between the rhizosphere and bulk soil(P<0.05).The levels of available phosphorus in the rhizosphere soil showed the highest increase in RS 1 plot,with an elevation of 75.00%,compared to the control group.In conclusion,R.soongorica rhizosphere soil displayed significantly higher bacterial diversity and soil enzyme activity than its bulk soil,thereby contributing to enhancing the microenvironment of desert soils.