Describe some differences between ectomycorrhizal fungi and arbuscular mycorrhizal fungi.

Question

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Answer 1

Ectomycorrhizae colonize the rhizoplane, the surface of plant rootlets—the most distal part of plant roots. The fungal mycelia never penetrate the root cells. They form a thick mantle surrounding the root and growing between the root cells, then extend long mycelia away from the root to absorb nutrients. Ectomycorrhizal fungi then give plants a portion of these nutrients in exchange for carbon (i.e. sugars from photosynthesis). Arbuscular mycorrhizal fungi also colonize the rhizoplane of plant roots, but unlike ectomycorrhizal fungi, they penetrate the root cells and make structures inside the plant cell for nutrient exchange and storage. Arbuscules are sites of nutrient exchange (obtain sugars as hexoses) and vesicles are storage organs. Like ectomycorrhizal fungi, arbuscular mycorrhizal fungi trade nutrients for carbon with the plant. Unlike ectomycorrhizal fungi (which colonize trees and shrubs), arbuscular mycorrhizal fungi colonize many of our crop plants.

Arbuscular mycorrhizal fungi are also ancestors of other fungi - they form their own monophyletic group. Ectomycorrhizal fungi diverged from saprotrophic fungi at least 50 times, so retain the capacity to break down soil organic matter (unlike arbuscular mycorrhizal fungi).