Stages in Lichen Re-Establishment

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Nitrogen Fixation by Symbiotic Blue-Green Algae Lichens Stages in Lichen RE Establishment Nitrogen Fixation and Assimilation

Stages in Lichen Re-Establishment

	Stages in Lichen Re-establishment The mechanism by which a photobiont acquires a mycobiont or vice-versa has been an interesting point of investigation in microbial ecology. When ascospores are liberated, some of them germinate to form a mycelial mat, at which stage, contact with alga; cells is established. An algal binding protein (lectin) which binding the photobiont cell wall to the fungal cell wall has been implicated in the process of recognition. The fungal mycelial mat eventually envelops the phycobiont cell.
Experiment son resynthesis of lichens in culture have revealed that green alga photobionts which happen to be the incorrect symbionts turn yellow and die while appropriate symbiotic photobionts remain green and healthy thereby suggesting that some sort of recognition phenomenon is operating. The establishment of symbiosis begins by carbohydrate transfer to the fungus and modification of symbiosis begins by carbohydrate transfer to the fungus and modification of the structure and physiology of symbiont cells. For example, cultured Nostoc cells are smaller than those in a symbiotic state.
In another case, in the lichen Nephroma laevigatum, the cyanobiont (Nostoc) gets enlarged and shapeless remaining as single cells whereas the same cyanobiont assumes a filamentous form in culture medium. The next step is the formation of a primordial lobe leading to the development of a mature thallus in about 5-6 months followed by spore formation.

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Blue Green Algal Association with Bryophytes Blue Green Algal Association with Higher Plants Aazolla Anabaena Asociation Survial of Aazolla Limitations of Aazolla Anabaena Asociation