多效唑对热区土壤细菌和真菌的影响及网络互作分析

Effect and Network in Teraction Analyses of Paclobutrazol on Bacteria and Fungi in Tropical Soils

植物生长调节剂多效唑在农业上使用广泛,有研究表明常年大量的施用多效唑不仅会影响作物生长,也会对土壤微生物多样性和群落结构带来一定的影响,但是关于多效唑影响热区土壤微生物的多样性和群落结构的研究鲜有报道。本文研究了多效唑在热区土壤中降解速率变化,发现热区土壤多效唑的初始施用浓度越高,则其降解速率越快。施药150d后,3和30mg/kg多效唑在土壤中的降解率分别达到63.84%和90.83%。通过高通量测序技术研究了不同浓度的多效唑原药对土壤微生物多样性及群落结构的影响,进一步构建微生物共现网络进行综合分析,发现多效唑改变了土壤细菌和真菌群落组成,随着多效唑施用时间的延长,绿弯菌门和壶菌门的相对丰度先增加后降低,酸杆菌门的相对丰度先降低后增加。施用多效唑显著降低土壤细菌多样性,促进土壤真菌丰富度的增加。网络分析结果表明,多效唑处理降低细菌和真菌互作网络的复杂度,对细菌和真菌互作产生一定影响,其影响随着施药时间的延长而逐渐减小。本项研究为在热区农业生产中合理施用多效唑提供了一定的科学依据。

The plant growth regulator paclobutrazol is widely used in agriculture.Studies had shown that a long-time and intensive application of paclobutrazol will not only affect the growth of crops,but also have a certain impact on soil microbial diversity and community structure.However,there are few published reports on the effects of paclobutrazol on microbial diversity and community structure in the tropical soils.In this study,the degradation rate of paclobutrazol in the tropical soils was investigated,which found that the higher the initial application concentration of paclobutrazol is,the faster the degradation rate would be.The degradation rates of 3mg/kg and 30mg/kg paclobutrazol reached 63.84%and 90.83%,respectively,after 150days of treatment in soils.The impacts of different concentrations of paclobutrazol in soil microbial diversity and community structure changes were studied through high-throughput sequencing technology.An integrated analysis was conducted by designing a microbial co-occurrence network.It was found that paclobutrazol could change the composition of soil bacterial and fungal communities.The relative abundances of Chloroflexi and Chytridiomycota increased firstly and then decreased over time after paclobutrazol treatment,while Acidobacteria abundance was decreased firstly and then increased.The diversity of bacteria was significantly reduced by paclobutrazol,while the richness of fungi was increased.The results of network analysis showed that the paclobutrazol was able to reduce its complexity and cause a certain negative effect on the interactions between bacteria and fungi,and that the effect would decrease gradually over application time.This study for the first time provided a scientific basis for the rational application of paclobutrazol in the tropical agricultural production.