Tiunov Alexei V, Scheu Stefan
Laboratory of Soil Zoology, Institute of Ecology and Evolution, Leninsky Prospect 33, 119071, Moscow, Russia.
Oecologia. 2005 Feb;142(4):636-42. doi: 10.1007/s00442-004-1758-1. Epub 2004 Dec 24.
The functioning of the plant-mycorrhiza system depends on interactions with other organisms, including saprotrophic (ST) soil fungi. The interactions between mycorrhizal and ST fungi are likely affected by fungivorous soil animals, such as Collembola. In a two-factorial laboratory experiment lasting for 30 weeks we assessed the effects of an arbuscular mycorrhizal fungus (Glomus mosseae) and Collembola (Protaphorura fimata, Heteromurus nitidus and Folsomia candida) on the community composition of ST microfungi in soil planted with the invasive grass Cynodon dactylon. The presence of mycorrhiza substantially reduced total plant biomass and reduced N and P availability to the soil microflora, though these effects were less pronounced in the presence of Collembola. The density of Collembola was high (corresponding to about 2x10(5) individuals m-2) and was not affected by the presence of G. mosseae. In spite of the large amount of mycorrhizal mycelium in soil, it contributed little to Collembola nutrition. The presence of mycorrhiza strongly affected the community structure of ST soil fungi. In particular, mycorrhiza reduced the relative abundance of Trichoderma harzianum and Exophiala sp., but increased the abundance of Ramichloridium schulzeri and several sterile forms. However, the difference between fungal communities in mycorrhizal and non-mycorrhizal treatments was much more pronounced in the presence of Collembola. Presumably, the intense grazing by Collembola destabilized the ST fungal community, thereby making it more susceptible to the influence of G. mosseae. These results document for the first time that fungal feeding soil invertebrates can significantly affect the interactions between mycorrhizal fungi and ST soil microorganisms.
植物-菌根系统的功能取决于与其他生物的相互作用，包括腐生（ST）土壤真菌。菌根真菌与ST真菌之间的相互作用可能受到食真菌土壤动物（如弹尾虫）的影响。在一项为期30周的双因素实验室实验中，我们评估了丛枝菌根真菌（摩西球囊霉）和弹尾虫（细角原跳、闪亮异跳和念珠弗氏跳）对种植入侵性禾本科植物狗牙根的土壤中ST微真菌群落组成的影响。菌根的存在显著降低了植物总生物量，并减少了土壤微生物可利用的氮和磷，不过在有弹尾虫存在时这些影响不太明显。弹尾虫的密度很高（相当于约2×10⁵ 个个体/平方米），且不受摩西球囊霉存在的影响。尽管土壤中有大量菌根菌丝体，但对弹尾虫营养的贡献很小。菌根真菌的存在强烈影响了ST土壤真菌的群落结构。特别是，菌根真菌降低了哈茨木霉和外瓶霉属的相对丰度，但增加了舒氏帚梗柱孢和几种不育形态的丰度。然而，在有弹尾虫存在的情况下，菌根处理和非菌根处理中真菌群落之间的差异更为明显。据推测，弹尾虫的强烈取食使ST真菌群落不稳定，从而使其更容易受到摩西球囊霉的影响。这些结果首次证明，以真菌为食的土壤无脊椎动物可显著影响菌根真菌与ST土壤微生物之间的相互作用。
