Wells John M, Donnelly Damian P, Boddy Lynne
School of Pure and Applied Biology, University of Wales, Cardiff, PO Box 915, Cardiff CF1 3TL, UK.
New Phytol. 1997 Aug;136(4):653-665. doi: 10.1046/j.1469-8137.1997.00776.x.
Development of mycelial cord systems of Phanerochaete velutina (DC.: Pers.) Parmasto from 4-cm inocula on a nutrient-depleted non-sterile soil was studied in laboratory microcosms using image analysis techniques. Cord systems were "baited" after 13d growth with either fresh, non-sterile 4-cm wood baits or control Perspex® blocks of the same contact area placed behind the foraging mycelial front. After 26 d growth, mycelial 'patches' arose by dedifferentiation of consolidated mycelial cords in both wood- and Perspex-baited cord systems. 'Patches' comprised fine, highly branched separate hyphae extending radially from points of aggregated hyphae in cords. 'Patches' and cords could be readily distinguished by image analysis and the areas covered by patches and cords could be measured and compared. Whilst the total hyphal cover of Perspex- and wood-baited systems did not differ significantly (P > 0.05), patch cover in wood-baited systems was up to 10 times greater than in Perspex-baited systems. Patches were temporary structures, regressing more rapidly with age than mycelial cords. Patch development ceased after application of a nutrient solution which replenished phosphate levels in the soil. Wood-baited mycelial systems displayed significant developmental polarity (P≤ 005) of both total hyphal cover (patches plus cords) and hyphae in patches towards the 'baited' sector of cord systems after 42 d, which corresponded with peak patch development. However, significant (P≤ 0.05) developmental polarity of the mycelial systems along the bait-inoculum line could be detected 8 d before patch formation when assessed by fractal geometry. Radiotracer studies showed that mycelial patches were not sinks for supplied P, but that they were sites of increased nutrient uptake capacity compared with that of mycelial cords. We discuss the need for mycelial cord systems to balance allocation of mycelial biomass between the two essential processes of colonizing wood resource units, and the acquisition of soluble inorganic nutrients from soil.
在实验室微观环境中，利用图像分析技术研究了在营养耗尽的非无菌土壤上，由4厘米接种体培养出的绒毛栓菌（Phanerochaete velutina (DC.: Pers.) Parmasto）菌丝索系统的发育情况。在生长13天后，用新鲜的、非无菌的4厘米木饵或相同接触面积的对照有机玻璃块“诱捕”菌丝索系统，将对照有机玻璃块放置在觅食菌丝前端的后方。生长26天后，在木饵和有机玻璃饵诱捕的菌丝索系统中，通过已固结的菌丝索去分化形成了菌丝“斑块”。“斑块”由从菌丝索中菌丝聚集点径向延伸的细小、高度分支的独立菌丝组成。通过图像分析可以很容易地区分“斑块”和菌丝索，并且可以测量和比较斑块和菌丝索覆盖的面积。虽然有机玻璃饵和木饵系统的总菌丝覆盖面积没有显著差异（P > 0.05），但木饵系统中的斑块覆盖面积比有机玻璃饵系统大10倍。斑块是临时结构，随着年龄增长比菌丝索退化得更快。在施用补充土壤中磷水平的营养液后，斑块发育停止。在42天时，木饵菌丝系统在总菌丝覆盖面积（斑块加菌丝索）和斑块中的菌丝方面，朝着菌丝索系统的“诱捕”区域显示出显著的发育极性（P≤0.05），这与斑块发育的高峰期相对应。然而，当通过分形几何评估时，在斑块形成前8天就可以检测到菌丝系统沿着饵 - 接种线的显著（P≤0.05）发育极性。放射性示踪研究表明，菌丝斑块不是供应磷的汇，但与菌丝索相比，它们是营养吸收能力增强的部位。我们讨论了菌丝索系统在定殖木材资源单元这两个基本过程之间平衡菌丝生物量分配以及从土壤中获取可溶性无机养分的必要性。
