The Structure and Function of the Vegetative Mycelium of Ectomycorrhizal Plants

SUMMARY It is increasingly evident that in natural plant communities the vegetative mycelia of ectomy‐corrhizal fungi can form networks of hyphal interconnections which link the root systems of their host plants in both intra‐ and inter‐specific combinations. Root observation chambers have been used to examine the development of these mycelial networks and to assess their functional significance as pathways for the transfer of assimilate between individuals in a range of host‐fungus associations. Carbon transfer between plants of Pinus spp. is significantly increased by the presence of mycelial connections and preliminary evidence suggests that such transfer may be enhanced where concentration gradients are induced by shading. The significance of these experimental results is discussed in relation to nutrient cycling processes in natural ecosystems.