Resuscitating an old thread, if anyone is still interested. This week's
Nature has an article that appears likely to be relevant :
http://www.nature.com/nature/journal...ture04590.html

In article _kIQf.196$Km6.54@trnddc01, Hanson wrote:
From: "hanson"
Newsgroups: sci.bio.botany,sci.chem,sci.geo.geology
Subject: Metals/Inorganics in Plants
Date: Sat, 11 Mar 2006 22:39:54 GMT

element or compound in tree bark that it burns with too much ash

"Bob" wrote in message
...
"Farooq W"
| More surprising the uptake of heavy metals especially
| Th and U by the plants...Barium is abnormally high or the
| soil on which that tree grew was rich in barium ores!

On Sat, 11 Mar 2006 02:27:31 GMT, "donald haarmann"
wrote:
The up take of uranium by plants is well know. See for example :-
Botanical Prospecting for Uranium on La Ventana Mesa, Sandoval
County New Mexico. US Geological Survey Bulletin 1009-M. 1956.
Some plants uptake serious amounts of selenium.

[Bob]
A Berkeley group is developing the use of a plant for Se
decontamination of soil. It is in field testing. (I could probably
find a ref if someone wants it.)
Then there are the Ni accumulators, which have several percent Ni in
their sap, nicely chelated (citrate, I think).
bob

[hanson]
=1= I posted this into sci.geo.geology in hope to get some views
from the geos' camp about the popularity & effectiveness of BP.
=2= As what/which compound does Si get into solution from the
calcogen silicates, considering that SiO4-- is stable only at
pH 11 in aq?
=3= in what soluble or sol-gel form is Silicon taken up
and transported in/to the plant (at a pH range ~ 7)
=4= As what/which compound is Si stored in the plant?
=5= and what function does the Si have in the plants?


Abstract:
Nature 440, 688-691 (30 March 2006) | doi:10.1038/nature04590; Received
5 September 2005; ; Accepted 18 January 2006
A silicon transporter in rice

Jian Feng Ma, Kazunori Tamai, Naoki Yamaji, Namiki Mitani, Saeko
Konishi, Maki Katsuhara, Masaji Ishiguro, Yoshiko Murata and Masahiro
Yano

Silicon is beneficial to plant growth and helps plants to overcome
abiotic and biotic stresses by preventing lodging (falling over) and
increasing resistance to pests and diseases, as well as other stresses.
Silicon is essential for high and sustainable production of rice, but
the molecular mechanism responsible for the uptake of silicon is
unknown. Here we describe the Low silicon rice 1 (Lsi1) gene, which
controls silicon accumulation in rice, a typical silicon-accumulating
plant. This gene belongs to the aquaporin family and is constitutively
expressed in the roots. Lsi1 is localized on the plasma membrane of the
distal side of both exodermis and endodermis cells, where casparian
strips are located. Suppression of Lsi1 expression resulted in reduced
silicon uptake. Furthermore, expression of Lsi1 in Xenopus oocytes
showed transport activity for silicon only. The identification of a
silicon transporter provides both an insight into the silicon uptake
system in plants, and a new strategy for producing crops with high
resistance to multiple stresses by genetic modification of the root's
silicon uptake capacity.

--
Aidan Karley, FGS
Aberdeen, Scotland,
Location: 57°10'11" N, 02°08'43" W (sub-tropical Aberdeen), 0.021233