Lichen is usually cited as an example of 'symbiosis' in plants where an algal and a fungal species live together for their mutual benefit. Whcih of the following will happen if algal and fungal partners are seperated from each other?
(a) Both will survive and grow normally and independent from each other.
(b) Both will die
(c) Algal component will survive while the fungal component will die.
(d) Fungal component will survive while algal partner will die.
Based on your answer how do you justify this association as symbiosis?
(b) is correct, lichen is symbiotic association between an alga and a fungi, which live together for their mutual benefit. If both are seperated from each other then they will die. The fungus holds water, provides protection and ideal housing to the alga.
The alga in turn supplies carbohydrate food for the fungus. If the alga is capable of fixing nitrogen (e.g., Nostoc), it supplies fixed nitrogen to the fungus. The kind of mutual interdependence helps lichen to grow on dry, barren rocks, where the other plants fail to exist. Morever, the algae or the fungi alone cannot grow in such places. Thus, both the partners cannot survive without each other.