Evolution of fungi/plants
JASON K. DOBRANIC
c0hx at UNBSJ.CA
Tue May 17 17:09:06 EST 1994
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
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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