THOUGHTS ON THE PROCESSES THAT MAINTAIN LOCAL SPECIES-DIVERSITY OF ECTOMYCORRHIZAL FUNGI
THOUGHTS ON THE PROCESSES THAT MAINTAIN LOCAL SPECIES-DIVERSITY OF ECTOMYCORRHIZAL FUNGI
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DOI：
10.1007/bf02183055
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发表时间：
1995-03-01
期刊：
影响因子：
4.9
通讯作者：
BRUNS, TD
中科院分区：
文献类型：
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作者：
BRUNS, TD
外生菌根真菌即使在小型的单作林中也表现出很高的多样性。大约有20到35个物种通常占据这样的位置。对这种多样性的解释可以基于资源分配、干扰、竞争或与其他生物的相互作用。菌根真菌竞争两大类资源：宿主来源的碳和土壤或碎屑来源的矿物质营养。两种类型的资源都在空间中排列（例如，土壤深度、距树的距离）和时间（例如，赛季，主持连续系列赛）。一些物种似乎在这些尺度上在空间和时间上被分割，但这些模式有多普遍的问题在很大程度上仍然没有答案。矿物资源分布在土壤、凋落物和其他土壤微生物中的离散基质中;真菌表现出的生物化学多样性可能转化为物种之间获得这些资源的差异。小规模的自然干扰，切断根，混合土壤层和凋落物层，或改变当地的pH值和养分的可用性，可能会创造外生菌根真菌的额外栖息地。从结果模式和殖民策略的差异的证据表明，这种干扰可能是重要的建立一些物种。物种之间的竞争性替代网络在理论上具有增加多样性的潜力。物种更替的频率，观察到的单一宿主根外生菌根真菌的共感染，和高速率的小根周转都表明，竞争是重要的，但它是否发挥了创造性的作用，在保持多样性仍有待证明。其他生物可能是重要的多样性的维护，如果它们之间的竞争影响菌根真菌。细菌和土壤无脊椎动物是最有可能发生这种相互作用的群体。根系观察和PCR鉴定真菌的技术进步使许多这些理论可以检验。
Ectomycorrhizal fungi exhibit high diversity even in small monoculture forests. Roughly 20 to 35 species typically occupy such sites. Explanations for this diversity can be based on resource partitioning, disturbance, competition, or interaction with other organisms. Mycorrhizal fungi compete for two general classes of resources: host-derived carbon and soil or detritus derived mineral nutrients. Both types of resources are arrayed in space (e.g., soil depth, distance from tree) and time (e.g., season, host successional series). Some species seem to be partitioned in space and time at these scales, but the question of how widespread these patterns are remains largely unanswered. Mineral resources are distributed in discrete substrates in soil, litter, and within other soil microorganisms; the biochemical diversity exhibited by fungi may translate into differences in access to these resources among species. Small-scale natural disturbances that sever roots, mix soil horizons and litter layers, or change local pH and nutrient availability, are likely to create additional habitats for ectomycorrhizal fungi. Evidence from fruiting patterns and differences in colonization strategies suggest that such disturbances may be important for establishment of some species. Competitive replacement networks among species have the theoretical potential to increase diversity. The frequency of species replacements, observed co-infections of ectomycorrhizal fungi on single host roots, and high rates of rootlet turn-over all suggest that competition is important, but whether it plays a creative role in maintaining diversity remains to be demonstrated. Other organisms could be important in the maintenance of diversity, if they effect competition among mycorrhizal fungi. Bacteria and soil invertebrates are the most likely groups for such interactions. Technological advances in root observation and PCR methods for identification of mycorrhizae make many of these theories testable.