A long time ago, when I was learning about plant ecotypes, I heard of
research on the adaptation of plants to high lead levels found in piles of
mine tailings. If I remember correctly, local races of plants were forming
that were able to adapt to toxic soils. This raises these questions: if
plants ARE NOT taking up the heavy metals, what is the mode of toxicity?
(Are ions in the soil blocking the uptake of needed substances?) What is
the mechanism of resistance that was evolving? If it involved the blocking
of uptake of lead and other metals, that implies that other, non-adapted
plants DO take them up.
Can any one comment on this aspect of the issue?
Martin M. Meiss
2011/4/15 Judy Che-Castaldo <[email protected]>
> Hi Ben,
> In general you are unlikely to find lead in the shoots of plants, because
> it
> is not very soluble and most plants exclude heavy metals. The edible
> plants
> that may have Pb would likely be leafy vegetables (grown close to the
> ground) and root vegetables (as mentioned earlier) because of the
> associated
> soil particles containing Pb.
>
> There are some plants that uptake heavy metals into their shoots but few
> for
> Pb, and even those may only do so under rare circumstances (such as
> phosphorous deficiency - Chaney 2007 J. Environ. Qual. 36:1429–1443). If
> you are interested in other contaminants you can look into the metal
> hyperaccumulation literature. Many of these plants are in the mustard
> family but probably are not normally eaten.
>
> best,
> Judy
>
>
> Judy Che-Castaldo
> BEES program, Biology Dept.
> University of Maryland
> (301)351-8290
> http://www.life.umd.edu/grad/BEES/students/che.html
>
