Partner give up to 90 of photosynthate to fungal

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: rs •  Trebouxia –  Most common genus associated with lichen partnerships –  Single ­celled rarely found as free ­living –  Found in temperate regions •  Trentepohlia –  Found in tropical regions Cyanobacteria Lichen Partners •  Found in about 10% of lichens •  Pel9gera –  Most common genus –  Found in dog lichen •  Some lichens have green algae & cyanobacteria •  Cephalodia – wart ­like structures on lichen surface –  Thought to use nitrogen fixing abili8es of cyanobacteria Forms of Lichens •  Lichen thallus – body of lichen •  Categories –  Foliose •  Flat & leaf ­like –  Fru8cose •  Erect & branch ­like –  Squamulose •  Small & scale ­like –  Crustose •  Flat & crust ­like 6 11/23/09 Structural OrganizaUon •  Many have well ­defined structures •  Typical structure –  Upper cortex –  Medulla –  Lower cortex –  Rhizinae •  Algal associa8ons also require gas exchange Physiology: Water Requirements •  Lack of water –  Lichens containing green algae absorb water from humid air & resume photosynthesis –  Lichens containing cyanobacteria must absorb liquid water to resume photosynthesis –  Drought tolerance is likely conferred by hydrophobins produced by lichen fungi –  Hydrophobin coated fungal hyphae create spaces for gas exchange Physiology: Nutrient Exchange Physiology: Nutrient Exchange •  Lichen fungi protect photosynthe8c partner & absorb nutrients •  Photosynthe8c partners provide sugars for the growth of lichen –  Very efficient at absorbing nutrients from limited environmental resources –  Unfortunately for lichens, also absorb toxins &...
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