Evolution of fungi/plants

JASON K. DOBRANIC c0hx at UNBSJ.CA
Tue May 17 17:09:06 EST 1994


In reply:

	I was taught that the Ascomycetes evolved from red algae, 
specifically parasitic forms.

	Another interesting idea which has come about is the evolution of 
vascular plants from an algal-fungal mutualism. Basically, it is thought 
that land plants originated from a green algae and an aquatic fungus, 
probably an oomycete. We can think of vascular plants like "inside-out" 
lichens. Much of this theory was devised from Peter Atsatt at UofCalifornia.
He got interested in the evolution of vascular plants from observations that 
there are many fungal-like cells in present day plants. The haustoria of 
parasitic plants are one example. Also, pollen tubes are strinkingly fungal 
in nature. Growth of the pollen tube is slow and involves enzymatic 
activity. Callose tissue forms in the wall surroundingthe developing 
microspore which is odd because callose is normally formed in response to 
wounding or parasitic infection. Therefore, the formation of callose may be 
seen as a reaction to parasitic elements carried by the elongation pollen 
tube. 
	This is all outlined in Peter Atsatt's paper entitled:" Are vascular 
plants "inside-out" lichens?" Ecology 69 (1), 1988, pp.17-23. I would 
recommend it to anyone interested in this idea. 
	I would like to hear your thoughts and/or concerns with is theory.



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