| 摘要: |
| 【目的】探讨丛枝菌根真菌（arbuscular mycorrhiza fungi,AMF）异形根孢囊霉（Rhizophagus irregularis，Ri）和摩西斗管囊霉（Funneliformis mosseae，Fm）根外菌丝对重金属铅的吸收及转运能力，为明确AMF根外菌丝的铅转运能力提供依据。【方法】以菌根植物蒺藜苜蓿（Medicago truncatula，寄主）和非菌根植物油菜（Brassica napus）为试验材料，采用三室培养系统（菌根室-施铅室-非菌根室）进行研究，其中菌根室种植蒺藜苜蓿并进行AMF处理，包括接种Ri、Fm和未接种对照（CK）3个处理；施铅室（中间隔室）设置0和800 mg/kg 2个铅处理；非菌根室种植油菜，试验共设CK、Ri、Fm、Pb、Ri×Pb、Fm×Pb 6个处理，研究铅胁迫下2种AMF根外菌丝对植物生长及铅离子富集的影响。【结果】（1）与CK处理比，Ri和Fm处理蒺藜苜蓿总生物量分别提高了43.55%和256.98%，铅胁迫对Ri和Fm处理蒺藜苜蓿的生物量无显著影响。（2）0 mg/kg 铅胁迫下，2种AMF均能够与蒺藜苜蓿形成良好共生关系，Fm和Ri处理菌根侵染率达到90%以上。Fm和Fm×Pb处理侵染根段丛枝丰度分别是Ri和Ri×Pb处理的8.75和2.51倍。（3）与Ri处理比，Ri×Pb处理菌根室培养基质中菌丝密度显著提高231.57%，施铅室培养基质中菌丝密度显著降低49.56%；与Fm处理比，Fm×Pb处理菌根室培养基质中菌丝密度提高314.09%，施铅室培养基质中菌丝密度降低21.09%。（4）Ri×Pb、Fm×Pb处理蒺藜苜蓿地上部铅含量分别是CK处理的3.60和8.45倍，根系铅含量分别是CK处理的7.45和217.87倍；Fm×Pb处理油菜根系铅含量是CK处理的62.15倍。【结论】AMF根外菌丝能够直接吸收并转运铅至寄主植物根部，并可能借由“外排”效应将铅运输至非菌根植物根系，且Fm促进植物生长及根外菌丝吸收转运铅的能力显著高于Ri。 |
| 关键词: 丛枝菌根真菌 根外菌丝 铅转运 菌根植物 |
| DOI： |
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| 基金项目:国家自然科学基金项目（31700530） |
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| Absorption and transport of heavy metal Pb by AMF extraradical mycelium |
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JIN Xiaoxia,WEI Man,CHENG Kang,et al
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| Abstract: |
| 【Objective】This study investigated the absorption and transport capacity of extraradical mycelium of arbuscular mycorrhizal fungi (AMF),Rhizophagus irregularis (Ri) and Funneliformis mosseae (Fm) on heavy metal Pb to provide basis for clarifying Pb transport capacity of AMF extraradical mycelium.【Method】The mycorrhizal plant Medicago truncatula and non-mycorrhizal plant Brassica napus were selected for tests in a three-chamber culture system (mycorrhizal chamber-Pb application chamber non-mycorrhizal chamber).M. truncatula was planted in the mycorrhizal chamber and treated with AMF including Ri,Fm,and non-inoculated control (CK).Two Pb treatments（0 and 800 mg/kg） were set in the Pb application chamber (middle compartment) and B. napus was planted in the non-mycorrhizal chamber.There were 6 treatments including CK,Ri,Fm,Pb,Ri×Pb,and Fm×Pb.The effects of extraradical hyphae of two AMF on plant growth and Pb enrichment under Pb stress were then studied.【Result】(1) Compared with CK,Ri and Fm treatments increased total biomass of M. truncatula by 43.55% and 256.98%,respectively,and Pb stress had no significant effect on biomass of M. truncatula with Ri and Fm treatments.(2) Under 0 mg/kg Pb stress,two AMF were able to form good symbioses with M. truncatula and the mycorrhization infection rates of Fm and Ri treatments were over 90%.The arbuscular abundance of infected root fragment in Fm and Fm×Pb treatments was 8.75 and 2.51 times of that in Ri and Ri×Pb treatments,respectively.(3) Compared with Ri treatment,the mycorrhizal hyphae density of culture substrate in mycorrhizal chamber of Ri×Pb treatment significantly increased by 231.57%,and mycorrhizal hyphae density of culture substrate in Pb application chamber significantly decreased by 49.56%.Compared with Fm treatment,mycorrhizal hyphae density of culture substrate of Fm×Pb treatment in mycorrhizal chamber increased by 314.09%,and mycorrhizal hyphae density of culture substrate in Pb treatment mycorrhizal chamber decreased by 21.09%.(4) The Pb contents M. truncatula shoots in Ri×Pb and Fm×Pb treatments were 3.60 and 8.45 times of that in CK treatment,the Pb contents of M. truncatula roots were 7.45 and 217.87 times of that in CK treatment,and the Pb content of B. napus roots in Fm×Pb treatment was 62.15 times of that in CK treatment.【Conclusion】AMF extraradical hyphae can directly absorb and transport Pb to roots of host plants,and may transport Pb to roots of non mycorrhizal plants by ‘efflux’ effect.The effect of F. mosseae on promoting plant growth as well as absorbing and transporting Pb by extraradical mycelium was significantly higher than that of R. irregularis. |
| Key words: arbuscular mycorrhizal fungi extraradical mycelium Pb transport mycorrhizal plant |
