7 fig 138 fig 137 le scanning electron micrograph of

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: e media –  Have lifle to no ability to degrade cellulose and lignin •  Rarely have high degree of host ­specificity Ectomycorrhizas •  Grouped into two types –  Mature •  Host restricted •  Mature trees •  Release proteases –  Providing ectomycorrhiza plants with nitrogen in the form of amino acids Ectomycorrhizas •  Grouped into two types –  Generalists •  Wide host range •  Young trees –  Such as Laccaria, Hebeloma, Thelephora terrestris Ectomycorrhizas •  Fungal Networking –  Extensive network of hyphae and mycelial cords •  Link different plants within a habitat •  Mycelial connec8ons retain mineral nutrients –  Withdraws nutrients from degenera8ng mycorrhizas –  Transports nutrients to other func8oning mycorrhizas •  Fungal network extends beyond root zone –  Mycelial cords transport water from deeper in the soil, beyond the reach of the roots 3 11/23/09 Fig 13.7 Fig 13.8 Fig. 13.7. Le>: Scanning electron micrograph of a cross sec8on of part of a mycorrhizal root, showing the fungal sheath that surrounds the root. Right: Thin sec8on of part of an ectomycorrhizal root. The arrowheads show hyphae invading between the root cor8cal cells, forming the Har8g net. Nutrient ­exchange between the fungus and the root is thought to occur in this interfacial region. Figure 13.8 A young larch seedling, about 3 cm high, growing in a peatbased substrate against a sloping face of an observa8on chamber. Mycoohizas can be seen at the base of the stem but almost all the visible growth is mycelial cords that explore the soil for nutrients. Ericoid Mycorrhizas Fig 13.10 •  Typical host families –  Ericaceae –  E...
View Full Document

This document was uploaded on 03/02/2014 for the course BIOL 4848 at Youngstown State University.

Ask a homework question - tutors are online