不同甘蔗品种根际土壤酶活性及微生物群落多样性分析

通过桶栽试验,比较了8个甘蔗品种吸氮效率的差异以及不同品种根际土壤酶活性和微生物群落多样性的差异,以期为甘蔗生产上的选种以及蔗地土壤生产力的维持提供科学支持。在甘蔗大生长期末期收集甘蔗植株和根际土壤,比较不同品种甘蔗植株的吸氮效率和氮肥利用率、测定根际土壤蔗糖酶以及脲酶活性、利用Miseq高通量测序技术对甘蔗根际细菌群落多样性进行分析。研究结果表明,不同甘蔗品种在大生长期末期的吸氮效率存在一定差异,8个品种的植株平均吸氮效率为17.95%~27.57%,氮肥利用率为22.15%~34.02%,其中吸氮效率及氮肥利用率最高的品种是‘桂糖44号’,最低的是‘桂选B9’;8个品种的根际土壤蔗糖酶活性3.51~6.56 mg/(g·d),脲酶活性1.12~ 1.42 mg/(g·d),不同品种间存在一定差异,土壤酶活性表现较高的品种为‘桂糖48号’和‘新台糖22号’,而‘粤糖93159’的土壤酶活相对较低。高通量测序分析结果显示,8个不同品种甘蔗根际土壤细菌种群结构存在一定差异,不同品种间在优势菌群组成上差异不显著,主要差异表现在优势菌属的丰度上,其中‘桂糖44号’和‘粤糖93159’均以Bacillus为最主要的优势菌属,而其他6个品种的主要优势菌属均为Chryseolinea。冗余分析结果显示,甘蔗氮吸收率、土壤碱解氮含量以及土壤pH对土壤微生物群落结构的影响最大;相关性分析表明,不同甘蔗品种吸氮效率的差异以及部分土壤理化指标均与根际土壤微生物群落中不同优势菌门存在一定的相关性;根系微生物菌群结构的差异可能在一定程度上影响了甘蔗的吸氮效率。本研究结果初步揭示了不同甘蔗品种氮肥利用率与根际微生物群落结构的相关关系,为深入研究甘蔗根际微生物多样性及功能与环境因子之间的关系提供了借鉴。

Analysis on Enzyme Activity and Microbial Community Diversity in Rhizosphere Soil of Different Sugarcane Varieties

In order to provide scientific support for the selection of sugarcane production and the maintenance of sugarcane soil productivity, the differences in nitrogen uptake efficiency of eight sugarcane varieties and the effects of different varieties on the enzyme activities and microbial community diversity in the rhizosphere soil were compared through the barrel cultivation experiment. Sugarcane plants and rhizosphere soils were collected at the end of large growth stage of sugarcane, and nitrogen utilization efficiency, invertase and urease activities in the rhizosphere soil of different sugarcane varieties were measured and compared. Meanwhile, the bacterial community structure of the sugarcane rhizosphere soil was determined and analyzed by the Miseq high-throughput sequencing technology. The nitrogen uptake efficiency of different sugarcane varieties was different. The average nitrogen uptake efficiency of the eight varieties was 17.95%-27.57%, and the nitrogen use efficiency was 22.15%-34.02%. The highest nitrogen uptake efficiency was for GT44, and the lowest was for B9. The invertase activity of the rhizosphere soil was 3.51-6.56 mg/(g·d), and there were significant differences among different cultivars. But the urease activity was 1.12-1.42 mg/(g·d), and there was few differences among different varieties. GT48 and ROC22 were the two varieties with higher soil enzyme activity in the rhizosphere. The results of high-throughput sequencing showed that there were some differences in the bacterial population structure in the rhizosphere soil of the eight sugarcane varieties, but there was no significant difference among different varieties in the composition of the dominant bacteria, and the main difference was in the abundance of the dominant genera. Bacillus was the dominant genus for GT44 and Y93159, while Chryseolinea was the dominant genus for the other six varieties. Redundancy analysis (RDA) showed that the nitrogen absorption efficiency of sugarcane, the content of available N and pH value of soil had the greatest effect on the soil microbial community structure. Correlation analysis showed that the nitrogen absorption efficiency of sugarcane and soil physiochemical characteristics were significantly correlated with different dominant microbial communities. This study would deepen the understanding of the microbial community in the sugarcane rhizosphere and provide references for the relation between the microbial composition and diversity with environmental factors.