菊芋根系分泌物改良滨海盐土的微生物机制  

Microbial Mechanism of Helianthus Tuberosus Root Exudates for Improving Saline-alkali Soil

作　　者：杨敏 李帅 曹慧翔 黄婷 李媛 谢军伟 赵耕毛[1] Yang Min;Li Shuai;Cao Huixiang;Huang Ting;Li Yuan;Xie Junwei;Zhao Gengmao(College of Resources and Environmental Sciences/Jiangsu Provincial Key Laboratory of Marine Biology, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China)

机构地区：[1]南京农业大学资源与环境科学学院/江苏省海洋生物学重点实验室,江苏南京210095

出　　处：《水土保持通报》2021年第6期71-81,共11页Bulletin of Soil and Water Conservation

基　　金：国家重点研发计划项目“滩涂增养殖技术与生态农牧化新模式”(2019YFD0900702,2020YFD0900703);国家自然科学基金中美联合项目(20191J006);山东省重点研发计划(2019JZZY020614)。

摘　　要：[目的]探究菊芋在滨海盐土改良过程中的作用机制,分析菊芋和碱蓬根系分泌物的组分差异,明确土壤微生态环境的变化规律,进一步为盐土改良提供理论依据。[方法]以种植菊芋和自然碱蓬植被为样地,对菊芋和碱蓬的根系分泌物进行对比分析,研究在根系分泌物作用下土壤微生物数量,微生物量碳氮,微生物群落结构以及土壤酶活性的变化,从而系统地阐明根系分泌物介导下盐土改良的微生物机制。[结果]菊芋根际土壤中含有果糖(2.343×10^(-3) g/kg)、葡萄糖(4.235×10^(-3) g/kg)、蔗糖(2.670×10^(-3) g/kg),分别是碱蓬根际土壤的9.28,1.52和2.43倍。而菊芋根际与非根际中的果糖含量存在显著性差异(p<0.05),其根际中含量为非根际的12.02倍。菊芋土壤还含有低聚果糖(蔗果三糖、蔗果四糖和蔗果五糖),而碱蓬土壤中未检测出低聚果糖。除糖类外,菊芋根系分泌物还含有烷烃、酚、醛、酯、有机酸、醇、酮、酰胺,其组分较碱蓬土壤更为复杂且某些组分为菊芋特有〔1-氯—十八烷、正十六烷酸、2-甲基-Z-4-十四碳烯、十二酮、(Z)-9-十八碳酰胺、苯丙酸十六烷基酯等〕。功能性根系分泌物(如低聚果糖、果糖、十六烷、十八烷酸等)为根际微生物提供碳源、氮源和营养元素的同时,使菊芋根际土壤中微生物数量显著增加(p<0.05),土壤微生物量碳、氮显著高于碱蓬土壤(p<0.05),其值分别是碱蓬土壤的1.95和1.6倍,且菊芋根际的微生物量碳、氮约为非根际的1.69和1.50倍,优势菌群(变形菌门、放线菌门、绿弯菌门、酸杆菌门)所占比重达到90%,土壤有益菌群(Actinobacteria和Acidobacteria)的相对丰度显著增加(p<0.05),土壤生物活性提升。此外,菊芋根际特有的分泌物(十六烷、烯醛等),抑制了病原菌的生长,优化了微生物群落结构。除过氧化氢酶外,土壤脲酶、蔗糖酶和碱性磷酸活性显著提高(p<0.05),其活�[Objective]The mechanism of Helianthus tuberosus in the improvement of coastal saline soil was explored,the compositional differences of root exudates of Helianthus tuberosus and Suaeda salsa were analyzed,and the changing laws of the soil micro-ecological environment were clarified,in order to provide a theoretical basis for saline soil improvement.[Methods]The root exudates of Helianthus tuberosus and Suaeda salsa were compared and analyzed,and the changes of soil microbial quantity,microbial biomass carbon and nitrogen,microbial community structure and soil enzyme activity under the action of root exudates were studied,so as to systematically clarify the microbial mechanism of saline soil improvement mediated by root exudates.[Results]The rhizosphere soil of Helianthus tuberosus contained fructose(2.343×10^(-3) g/kg),glucose(4.235×10^(-3) g/kg),and sucrose(2.67×10^(-3) g/kg),which were 9.28,1.52,2.43 times of that in Suaeda salsa rhizosphere soil.The difference between contents of fructose in the rhizosphere and non-rhizosphere of Helianthus tuberosus was significant(p<0.05),and the content in the rhizosphere was 12.02 times of that in the non-rhizosphere.Helianthus tuberosus soil also contained oligofructose(sucrose triose,sucrose tetraose and sucrose pentaose),but no fructooligosaccharides were detected in the soil of Suaeda salsa.In addition to sugars,Helianthus tuberosus root exudates also contained alkanes,phenols,aldehydes,esters,organic acids,alcohols,ketones,and amides.Its components were more complex than Suaeda salsa soil and some components were unique to Helianthus tuberosus〔1-Chloro-octadecane,n-hexadecanoic acid,2-methyl-Z-4-tetradecene,dodecone,(Z)-9-octadecyl amide,and hexadecyl phenylpropionate Esters.〕.Functional root exudates(such as oligofructose,fructose,hexadecane,and octadecanoic acid.)provided carbon source,nitrogen source and nutrient elements for rhizosphere microorganisms.The number of microorganisms in the rhizosphere soil of Helianthus tuberosus increased significantly(p<0.0

关 键 词：菊芋 根系分泌物 盐土改良 益生作用 微生物区系 土壤生物活力 

分 类 号：S156.4[农业科学—土壤学]