Question

Who are the two partners in :a) lichen mutualism and b) mycorrhizal mutualism? what does each partner contribute to each of these relationships? Given the fungal lifestyle as an absorptive heterotroph, why might fungal associations with photosynthetic organisms, as in mycorrhizae and lichens, be an alternative to being a decomposer?

Answer 1

Ans 1. (a) in Lichen mutualism two parteners are fungus and alga (cynobacteria)
           (b) in mycorrhizal mutualism two parteners are fungi and plant roots

Ans 2. lichen mutualism : Fungus provides rooted structural protection includina a base on which the algae grows and attached to a tree, wall
Algae supplied fungus with nutrients such a s glucose from photosynthesis and oxygen from respiration.
mycorrhizal mutualism : fungus receives products of photosynthesis from plant and at same time fungus grows out in to the soil and retrieves nutrients and passes back to the plant .

Ans 3 The absorptive lifestyle of fungi is associated with two important characterstics
production of spores and hypha (mycelial growth)
The production of many tiny spores increases the chance that at least a few will fall onto a suitable food source, germinate, and start absorbing food, and then growing into a thread-like hypha , which develops right after spore germination, puts out powerful enzymes needed to digest food for the fungus.the mycelium is well-suited to absorbing food. It has a high surface-volume ration permitting the surface exposed to the external food source to absorb enough food to nourish the enclosed body of cytoplasm.

As decomposers, the fungi are vitally important members to the plant and animal kingdoms. When a dead leaf drifts to the forest floor or an animal dies of disease, fungal and bacterial spores floating in the air have already settled on it. These spores quickly germinate and begin to break down the dead organism, releasing small organic molecules that can be used as food, as well as minerals that may be absorbed by the decomposer or by nearby plants.
Fungi, together with bacteria, are responsible for most of the recycling which returns dead material to the soil in a form in which it can be reused.
And in fungal association with other photosynthetic organism they work together for absorbing food and balancing the ecosystem.