[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Iron, chelates, and pathways

Oops! I said in the last message that ONLY Fe2+ is absorbed into the
plant root or leaf. That's not quite accurate. There is another
mechanism called Strategy 2 which involves phytosiderophores. I've taken
the liberty of quoting the description:

"Strategy 2 - Monocotyledonous plants (grasses)

This uses Fe complexing compounds called phytosiderophores to mobilize
Fe in the rhizosphere (see the summary diagram below). The
phytosiderophores (negatively charged amino acids) are released by a
specific transporter (an anion antiport ?) into the soil. They then
diffuse towards Fe(OH)3+ where they complex Fe. They can then diffuse
back to the root where the whole complex is taken back up into the root
(by a H+-symporter). The Fe3+ is not reduced to Fe2+ and the chelator
does not return directly back to the soil (as in Strategy 1 plants). In
the soil the phytosiderophores can become sorbed to the anion exchange
phase (as they are strongly negatively charged) or they can be ingested
and decomposed by the soil's microbial biomass. "

Does anyone know if any aquatic plants give off phytosiderophores? Do
all monocots possess this characteristic?

Steve in Vancouver