Wells John M, Harris Melanie J, Boddy Lynne
School of Pure and Applied Biology, University of Wales, Cardiff, PO Box 915, Cardiff CF1 3TL, UK.
To whom correspondence should be addressed. E-mail:
New Phytol. 1998 Oct;140(2):283-293. doi: 10.1046/j.1469-8137.1998.00268.x.
Mycelial cord systems, up to 50-cm diameter, of the basidiomycete Phanerochaete velutina (DC.: Pers.) Parmasto, a common woodland saprotroph, grown on non-sterile soil in model laboratory microcosms were baited, after 27 d, with pairs of fresh beech wood blocks (baits), placed at 10 d intervals behind the foraging colony margin. System development was quantified by image analysis. Mean radial extent and hyphal cover increased linearly with time until day 21, but declined before the mycelial systems reached the edges of the laboratory microcosms. The mass (D ) and border (D ) fractal dimensions of the mycelial systems changed with time but the ratio D ∶D became constant after 14 d. A separate central compartment containing the inoculum was supplied with P orthophosphate and its translocation to wood baits monitored non-destructively for 73 d. Whilst total P acquisition by wood baits increased linearly with time, the proportion of total allocated to baits varied significantly both temporally and according to the length of time that baits had been in contact with the mycelium. Most recently supplied wood baits were not the main sink for supplied phosphorus; rather, the rate of P acquisition was initially greatest in baits from which egress of the fungus had already occurred. The rate of P acquisition by the most recently added baits increased with time, supported by efflux from other wood baits, which had initially been the main sinks for translocated phosphorus. The results raise important questions about the ecological and functional significance of nutrient partitioning in cord systems and imply that 'observed' translocation, rather than being an absolute measure, indicates the degree to which phosphorus is loaded from a translocation stream in regions where it is being actively utilized and/or stored.
在模型实验室微观环境中的非无菌土壤上生长的担子菌绒盖拟层孔菌（Phanerochaete velutina (DC.: Pers.) Parmasto），一种常见的林地腐生菌，其直径达50厘米的菌丝索系统在27天后，用成对的新鲜山毛榉木块（诱饵）进行诱捕，诱饵每隔10天放置在觅食菌落边缘后方。通过图像分析对系统发育进行量化。平均径向范围和菌丝覆盖面积在第21天之前随时间呈线性增加，但在菌丝系统到达实验室微观环境边缘之前下降。菌丝系统的质量（D）和边界（D）分形维数随时间变化，但D∶D的比值在14天后变得恒定。一个单独的包含接种物的中央隔室供应正磷酸盐，并对其向木诱饵的转运进行73天的无损监测。虽然木诱饵对总磷的获取量随时间呈线性增加，但分配给诱饵的总磷比例在时间上以及根据诱饵与菌丝体接触的时间长短均有显著变化。最近供应的木诱饵并非供应磷的主要储存库；相反，磷获取率最初在真菌已经从中逸出的诱饵中最高。最近添加的诱饵的磷获取率随时间增加，这得益于其他木诱饵的磷外流，而其他木诱饵最初是转运磷的主要储存库。这些结果引发了关于菌丝索系统中养分分配的生态和功能意义的重要问题，并表明 “观察到的” 转运并非绝对测量值，而是表明在磷被积极利用和 / 或储存的区域中，磷从转运流中被加载的程度。
