缩节胺和硝普钠对棉花幼苗根际土壤酶活性及细菌群落的影响

Foliar application of 1,1-dimethyl piperidinium chloride and sodium nitroprusside effects on soil enzyme activities and rhizosphere bacterial community of cotton seedlings

【目的】研究棉花幼苗施用缩节胺(1,1-dimethyl piperidinium chloride,DPC)和一氧化氮供体硝普钠(sodium nitroprusside,SNP)后根际土壤酶活性及细菌群落的变化,探讨与棉花幼苗生长相关的根际生物学指标。【方法】采用陆地棉品系A201进行穴盘育苗试验。于棉花1叶1心期分别在叶片均匀涂抹50 mg·L^(-1)DPC、500μmol·L^(-1)SNP,以涂抹去离子水为对照。于3叶1心期取根际土壤分析蔗糖酶、脲酶、过氧化氢酶、碱性磷酸酶活性,采用16S rRNA测序技术分析根际细菌多样性。【结果】DPC和SNP处理显著促进棉花根系生长,显著提高茎粗和植株干物质质量。DPC处理显著提高土壤脲酶和蔗糖酶的活性,SNP处理显著提高土壤蔗糖酶活性但显著降低脲酶的活性,但是DPC和SNP处理均未显著影响过氧化氢酶和碱性磷酸酶活性。DPC处理显著提高髌骨菌门(Patescibacteria)的相对丰度和土壤细菌群落的辛普森多样性指数(Simpson's diversity index),显著降低了绿弯菌门(Chloroflexi)和酸杆菌门(Acidobacteria)的相对丰度以及土壤细菌群落的香农-维纳多样性指数(Shannon Wiener’s diversity index)。冗余分析显示,DPC处理组的酵母菌科(Saccharimonadaceae)、TM7a属细菌的相对丰度比SNP处理组和对照组高;SNP处理组的纤维弧菌属(Cellvibrionaceae)细菌相对丰度高于DPC处理组和对照组;DPC和SNP处理组的根瘤菌科(Rhizobiaceae)细菌的相对丰度高于对照组,硝化螺旋菌科(Nitrospiraceae)和硝化螺旋菌属(Nitrospira)细菌的相对丰度低于对照组。脲酶活性与酵母菌科、TM7a属细菌的相对丰度呈显著正相关关系。【结论】DPC和SNP能够促进棉花幼苗根系及植株生长,并影响棉苗根际的土壤酶活性及细菌群落结构。

[Objective]The study aims to examine the rhizosphere soil enzyme activity and bacterial community response to foliar application of 1,1-dimethyl-piperidinium chloride(DPC)and sodium nitroprusside(SNP)at the cotton seedling stage,and to screen rhizoshpere events potentially involved in cotton seedling growth.[Method]An upland cotton line A201 was grown in nursery trays under a controlled environment.The treatment with DPC of 50 mg·L^(-1)and SNP of 500μmol·L^(-1),respectively,was foliar-applied at the one-leaf-one-heart stage,and the treatment with deionized water application was selected as the control.The rhizosphere soil was sampled to quantify the activities of sucrase,urease,catalase,and alkaline phosphate at the three-leaf-one-heart stage.The rhizosphere bacteria composition examined by 16S rRNA sequence analysis.[Result]The root growth,stem diameter,and dry mass of whole cotton plant were significantly increased by the DPC and SNP treatments.The activities of urease and sucrase were significantly improved by the DPC treatment.SNP application significantly enhanced sucrase activity but significantly decreased urease activity,while DPC treatment and SNP treatment had no significant effect on the activities of catalase and alkaline phosphatase.DPC application increased the relative abundance of Patescibacteria and Simpson's diversity index of soil bacterial community,but reduced the relative abundances of Chloroflexi and Acidobacteriota and Shannon Wiener’s diversity index of soil bacterial community.The results of redundancy analysis on family and genus level showed that the abundances of Saccharimonadaceae and TM7a were higher in the DPC treatment;the abundance of Cellvibrionaceae was greater in the SNP treatment;the abundance of Rhizobiaceae was greater in the DPC and SNP treatments.The control exhibited greater Nitrospiraceae and Nitrospira abundances compared with the DPC and SNP treatments.Urease activity was positively correlated with Saccharimonadaceae and TM7a relative abundances.[Conclusion]DPC and SNP could promote the growth of cotton roots and aerial parts,and influence the soil enzyme activity and bacterial community composition in the rhizosphere.