入侵植物光梗蒺藜草对土著丛枝菌根真菌群落的影响

摘要

运用 T -RFLP 及定量 PCR 的方法探讨了内蒙古温带草原上光梗蒺藜草（Cenchrus incertus M.A.）入侵对AM真菌群落的影响。研究结果表明，光梗蒺藜草能够与 AM真菌形成良好共生关系，但与本土优势植物相比，光梗蒺藜草根际土壤中的 AM真菌丰度显著降低，AM真菌群落结构也发生明显变化。两种植物根际土壤中 AM真菌优势种相同，均属于 Glomus 属，T -RFLP 带型为 T -RF 524 bp 和280 bp，与 Maarj AM数据库匹配的 AM真菌虚拟种（virtual taxa）为 VT109及 VT287。此外，Rhizophagus intraradices（VT113，T -RF141 bp）及 Diversispora sp.（VT60，T -RF136，141 bp）在入侵植物根际土壤及根系中均显著高于本土植物，而 Glomus 属的其它 T -RFLP 带型在本土植物根际土壤和根系中显著高于入侵植物。两种植物根际和根中 AM真菌群落结构一致。初步揭示了光梗蒺藜草对本土 AM真菌的影响，为探明光梗蒺藜草入侵机制及其防治提供了一定研究基础。%The AMfungal community composition both in roots and rhizosphere soils of the invasive plant Cenchrus incertus and the dominant native plant Setaria viridis in a typical steppe in Inner Mongolia were examined by using terminal restric-tion fragment length polymorphism analyses (T -RFLP).The results showed that AMfungal abundance in the rhizosphere soil of C.incertus was significantly lower than that of S.viridis.The AM fungal community composition in the rhizosphere soil of the two plant species also largely differed.In general,AM fungal community structures in roots corresponded very well to that in rhizosphere soils for both plant species.The dominant AMfungal type both in invasive and in native plants was T -RFLP 524 bp,which represents Glomus sp.(Virtual taxa 109 and 287).Three specific T -RF types (280,190 and 141 bp)were significantly higher with C.incertus,representing three clusters in Glomus which also named as VT (vir-tual taxa)287,64 and 214,Rhizophagus intraradices(VT 113)and Diversispora sp.(VT 60).While the specific T -RF types,189 and 279 bp,for S.viridis,only existed in Glomus cluster 1 (VT 156 ),were significantly lower with C.incertus.These results indicated that AMfungi may play an important role in the invasion process of C.incertus,which still need further investigations.