Chamier Anne-Carole, Dixon Peter A, Archer Simon A
Department of Botany, Royal Holloway College, Egham, Surrey, U.K.
Department of Pure and Applied Biology, Imperial College, Prince Consort Road, S.W.7, London, U.K.
Oecologia. 1984 Sep;64(1):92-103. doi: 10.1007/BF00377550.
Transects were cut from alder leaves incubated in a freshwater stream and plated as quadrats so that fungal isolates could be mapped by reconstruction of each transect. Initially there was fewer than one aquatic hyphomycete colonist per quadrat, but the mode increased to 6-7 then progressively decreased to <1. Numbers of species of aquatic hyphomycetes per quadrat rose and fell similarly with a maximum mode of 3-4, as did species per transect with a maximum of 11 and a diversity of 16, comprising 6 'dominant' species and about 10 'occasional' species. The latter showed no pattern of appearance but the dominant group was established early and persisted in a dynamic equilibrium. Aquatic hyphomycetes were initially randomly distributed but developed progressively into clumped consortia which persisted after peak colonization, declining as leaf degradation became total. Colonies of the most persistent aquatic hyphomycete species were initially discrete,developing into a complex network of overlapping colonies and species, no two of which showed positive association. These complexes broke down to large colonies of a few species and finally to 1-2 small colonies. The pattern of isolates of the 18 genera of other fungi was the reverse of that for aquatic hyphomycetes. Only Cladosporium, Epicoccum and Fusarium were important colonizers. The first two appear to be inhibited by aquatic hyphomycetes, but were found to degrade substrates representative of cell-wall polymers vigorously whereas aquatic hyphomycetes showed varied degradative ability. Leaf transects were examined by S.E.M. and epifluorescent microscopy so that hyphal colonization could be followed at progressive stages of leaf degradation. Bacteria on transects were patchily distributed, the temporal pattern indicating inhibition by aquatic hyphomycetes and colonization of senescent hyphae.
从在淡水溪流中培养的桤木叶上切取横断面，并以样方形式进行接种，以便通过重建每个横断面来绘制真菌分离株的分布图。最初，每个样方中水生真菌的定殖者少于1个，但随后这一数值增加到6 - 7个，然后逐渐减少至小于1个。每个样方中水生真菌的物种数量也有类似的增减，最高模式为3 - 4种，每个横断面的物种数量最多为11种，多样性为16种，其中包括6种“优势”物种和约10种“偶见”物种。后者没有出现规律，但优势菌群建立较早并在动态平衡中持续存在。水生真菌最初随机分布，但逐渐发展成簇状群落，在定殖高峰期后持续存在，随着叶片完全降解而减少。最持久的水生真菌物种的菌落最初是离散的，发展成一个由重叠菌落和物种组成的复杂网络，其中没有两个显示出正相关。这些复合体分解为少数物种的大菌落，最终变为1 - 2个小菌落。其他18属真菌的分离株模式与水生真菌相反。只有枝孢属、附球菌属和镰刀菌属是重要的定殖者。前两者似乎受到水生真菌的抑制，但发现它们能有力地降解代表细胞壁聚合物的底物，而水生真菌的降解能力各不相同。通过扫描电子显微镜（S.E.M.）和落射荧光显微镜对叶片横断面进行检查，以便在叶片降解的不同阶段追踪菌丝定殖情况。横断面上的细菌分布不均，时间模式表明受到水生真菌的抑制以及衰老菌丝的定殖。
