接种菌根真菌与施磷对豆禾混播体系生物量及竞争力的影响

Effects of Mycorrhizal Fungi Inoculation and Phosphorus Addition on the Biomass and Competitiveness of Legumes-grasses Mixture System

丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)是陆地生态系统中一类重要的土壤微生物,能与约80%的陆地植物形成互利共生关系。本研究通过构建紫花苜蓿(Medicago sativa)单播、无芒雀麦(Bromus inermis)单播、紫花苜蓿与无芒雀麦(1∶1)混播组合,设置接种AMF和磷添加处理,探讨土壤有效磷水平与AMF互作对紫花苜蓿和无芒雀麦混播体系地上生物量及竞争力的影响。结果表明:与不接种AMF处理相比,接种AMF处理下紫花苜蓿单播体系地上生物量提高17.59%,无芒雀麦单播和混播地上生物量分别降低10.23%和10.26%。施磷处理下,接种AMF对单播和混播地上生物量无显著影响。混播体系中无芒雀麦的地上竞争率大于紫花苜蓿,接种AMF对紫花苜蓿地上竞争率无显著影响,使无芒雀麦地上竞争率降低56.41%。接种AMF使混播体系中紫花苜蓿地上磷吸收量提高66.12%,对无芒雀麦地上磷吸收量无显著影响,缓解了无芒雀麦对紫花苜蓿的竞争排除作用。综上所述,紫花苜蓿与无芒雀麦构建的(1∶1)混播体系中AMF能有效抑制禾草无芒雀麦的地上竞争力,利于豆禾混播体系的维持。

Arbuscular mycorrhizal fungi(AMF)is a kind of soil microorganisms in terrestrial ecosystems,which can form symbiotic relationships with about 80%of terrestrial plants.In this study,the effects of AMF inoculation,phosphorus addition,and planting patterns(M.sativa monoculture,B.inermis monoculture,and mixed culture)on the shoot biomass and competitiveness were investigated in greenhouse cultivation conditions.The results showed that compared with no AMF inoculation,AMF inoculation significantly increased the shoot biomass of M.sativa monoculture by 17.59%,but decreased that of B.inermis monoculture and mixed culture by 10.23%and 10.26%,respectively.In P addition plots,AMF inoculation had no significant effect on aboveground biomass in monoculture and mixed sowing systems.In a mixed sowing system,the aboveground competition ratio of B.inermis was larger than that of M.sativa.AMF inoculation had no effect on that of M.sativa,but decreased the aboveground competition ratio of B.inermis by 56.41%.AMF inoculation significantly enhanced the shoot P uptake of M.sativa,but did not alter that of B.inermis.In summary,in the M.sativaand B.inermis mixed(1∶1)sowing system,AMF inoculation can inhibit the aboveground competitiveness of B.inermis,and it is conducive to the maintenance of the legume-grass mixed sowing system.