Phytochelatin Synthase and chelation

[plasmodesmata11]

All right, I need a little help:
Chelation is a process, in plants at least, where trace elements (heavy metals) are absorbed in a soluble, but bound manner.
How does the plant utilize them from there? Also, uptake of iron, I hear, is necessary through a chelating agent because it will form a precipitate with phoshphorous. Why?
And a few other things:
Where is PCS located?
Are only three amino acids (glycine, glutamic acid, and cysteine) present in phytochelatins?
What are some of the effcts of mycorrhizal fungi on TE uptake? and general info (like habitat, etc.)
Also, general info on Metallothioneins would be appreciated.
Thanks

[vietknight]

Phytochelatins are oligomers of Glutathione, so yes they consist of just Glycine, glutamic acid and cysteine. Most organisms in general do not utilize heavy metals, infact they are quiet toxic especially to humans and plants. Plants chelate the heavy metals to keep them from disrupting and competing with other essential metals such as Ca+/Na+ transport channels.

http://www.healthatoz.com/healthatoz/At ... soning.jsp

http://en.wikipedia.org/wiki/Phytochelatin
http://en.wikipedia.org/wiki/Metallothionein

[plasmodesmata11]

Thank you!