Chilvers G A, Lapeyrie F F, Horan D P
Department of Botany, Australian National University, P.O. Box 4, Canberra City, A.C.T. 2601, Australia.
New Phytol. 1987 Oct;107(2):441-448. doi: 10.1111/j.1469-8137.1987.tb00195.x.
Vesicular-arbuscular (VA) mycorrhizal fungi and ectomycorrhizal fungi were observed together in the same root system, and even within the same root apices, of seedlings of Eucalyptus dumosa A. Cunn. ex Schau. On a population basis, there was a succession of two overlapping mycorrhizal epidemics-VA mycorrhizas followed by ectomycorrhizas. This succession was interpreted as follows. Early build-up of VA mycorrhizas was related to initial higher inoculum potential of that fungus and to rapidity of colonization of individual roots. The ectomycorrhizal fungus was more successful later in achieving secondary infections by hyphal spread and in colonization of lateral root branches. The ectomycorrhizal fungus had no difficulty infecting pre-existing VA mycorrhizas, but the ectomycorrhizal sheath provided a barrier to subsequent VA mycorrhizal infections. While the proportion of VA mycorrhizas to ectomycorrhizas changed between two and five months, the overall proportion of mycorrhizal roots remained constant, suggesting that there could be competition between the different fungi for limiting substrate.
在杜氏桉（Eucalyptus dumosa A. Cunn. ex Schau.）幼苗的同一根系中，甚至在同一根尖内，都同时观察到了泡囊-丛枝（VA）菌根真菌和外生菌根真菌。从种群角度来看，存在着两种重叠的菌根流行序列——先是VA菌根，随后是外生菌根。这种序列可作如下解释。VA菌根的早期形成与该真菌最初较高的接种潜力以及单个根系的定殖速度有关。外生菌根真菌后来通过菌丝蔓延实现二次感染以及在侧根分支上定殖更为成功。外生菌根真菌感染先前已有的VA菌根并无困难，但外生菌根鞘为随后的VA菌根感染提供了一道屏障。虽然在两到五个月期间VA菌根与外生菌根的比例发生了变化，但菌根根系的总体比例保持不变，这表明不同真菌之间可能会竞争有限的底物。
