碳添加促进丛枝菌根真菌与铁还原菌双接种的玉米对砖红壤磷素吸收与利用  

Exogenous Carbon Increased Phosphorus Transformation and Utilization Inoculated with AM and Iron-reducing Bacteria in Maize in Latosol Soil

作　　者：冀春花[1,2] 刘敏[2] 李继峰 张士荣 丁效东[3] 侯玉雪[3] 冯固 JI Chunhua;LIU Min;LI Jifeng;ZHANG Shirong;DING Xiaodong;HOU Yuxue;FENG Gu(College of Resources and Environment, China Agricultural University, Beijing 100109, China;Hainan Academy of Agricultural and Reclamation Science, Haikou 570311, China;College of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, China)

机构地区：[1]中国农业大学资源与环境学院,北京100109 [2]海南省农垦科学院,海南海口570311 [3]青岛农业大学资源与环境学院,山东青岛266109

出　　处：《青岛农业大学学报（自然科学版）》2020年第3期212-218,共7页Journal of Qingdao Agricultural University(Natural Science)

基　　金：海南省自然科学基金青年基金项目(318QN298);国家重点研发计划项目(2017YFD0200208-3)。

摘　　要：砖红壤对磷素固定能力强,利用效率低,本研究以玉米为供试作物,揭示外源碳添加对丛枝菌根(AM)真菌与铁还原菌(IRB)互作提高砖红壤磷素活化和吸收利用的调控机制。采用两室根箱装置,用30μm尼龙网分隔成两个隔室,一室为根室(接种AM真菌),另一室为菌丝室,菌丝室添加15 mg/kg P2O5(KH2PO4)。菌丝室设接种IRB和碳添加两因素处理:(1)三个碳水平(以碳量计),即0 mg/kg(C1)、5 mg/kg(C2)、50 mg/kg(C3);(2)两个接种水平,即接种铁还原菌(IRB+)和不接种铁还原菌(IRB-)。结果表明,在接种IRB处理时,随外源碳含量增加,玉米地上部干重、磷含量增加,且在C3处理时最高;接种IRB处理时,菌根侵染率及菌丝际土壤菌丝密度表现为C3>C2>C1。在同一碳处理下,与不接种IRB处理相比,接种IRB处理时C2、C3处理的菌根侵染率分别提高21%、67%;接种IRB处理的土壤菌丝密度均显著高于不接种IRB处理,表明在接种IRB同时增加碳源供应时,AM真菌与玉米根系形成良好的菌根共生体系;接种IRB时添加50 mg/kg碳显著增加菌丝际土壤有效磷、水溶性磷及微生物量磷含量,与5 mg/kg碳水平相比分别增加20%、26%、29%,同时降低土壤Fe-P含量。综上所述,在砖红壤中AM真菌和IRB之间存在相互促进机制,菌丝际增加外源碳(50 mg/kg)显著提高了IRB对土壤固定态Fe-P的活化与释放,进而促进菌根化玉米对磷素吸收和利用。Focus on the high phosphorus fixation and low utilization efficiency in south China latosol soil,a pot experiment was carried out to study the mechanisms of phosphorus activation and utilization under the interaction of arbuscular mycorrhizal fungi and iron-reducing bacteria with exogenous carbon in brick red soil.Two-compartment root box was used,which was separated with 30μm nilon mesh,one was for root inoculated with AM fungi,the other was for mycelium with 15 mg/kg P(KH2PO4)addition,and mycelium part was inoculated with or without iron-reducing bacteria(IRB)under 0,5 and 50 mg/kg C levels.The results showed that,under IRB inoculation,the dry weight of the shoots and phosphorus content of the plant were significantly increased with exogenous carbon addition.Meanwhile,the mycorrhizal inoculate rate and mycelial density in hyphosphere soil with IRB inocalation were also increased with exogenous carbon addition.With the same C addition,compared with no IRB inoculation treatments,the mycorrhizal infection rate of C2 and C3 treatments were increased by 21%and 67%,respectively.And the mycelial density with IRB inoculation treatment was significantly higher than that without IRB inocalation treatment,which meant that a good symbiotic system between AM fungi and the root of maize was formed with both IRB inoculation and exogenous carbon addition.The content of available phosphorus,water-soluble phosphorus and microbial biomass phosphorus(MBP)in soil were increased in inoculation of IRB with 50 mg/kg C addition treatment,compared with 5 mg/kg C level,which was increased by 20%,26%and 29%,respectively,while the Fe-fixed P content in soil was reduced.In summary,mutual promotion mechanism between AM fungi and IRB in latosol was found,and the exogenous carbon(50 mg/kg)addition in hyphosphere soil promoted the activation and release of Fe-P by iron-reducing bacteria,which improved the phosphorus uptake and utilization by mycorrhizal maize.

关 键 词：丛枝菌根真菌 铁还原菌 外源碳 土壤磷素 微生物量磷 

分 类 号：Q949.748.5[生物学—植物学]