PLANT EXPERTS: How are metals absorbed by plants?

Question

We just did an experiment in Biology to determine whether or not plants could absorb heavy metals, such as lead and nickel. We determined through chromatography tests that these metals can be absorbed.

Now we need to know how.

SOURCES WOULD BE GREAT.

Answer 1

Hmm well. To be absorbed by plants metals need to be in a soluble form ie ions/salts.

I'm not quite sure on what sorts soluble salts would be naturally occurring for lead/nickel but maybe you could  ask in chemistry about that.

Once the ions are in the soil they are actively taken up by the plant via the root hair cells or more passively absorbed via diffusion. It seems to depend on the concentration of ions in the plant, in some cases this is 1000's of times greater than in the soil.

http://www.soils.umn.edu/academics/class...

The rate at which these metals are taken up is heavily dependent on the pH of the soil, as at certain pH levels these nutrients become 'locked up' in solid form and are unavailable to the plants.

You may be interested to know that this process has been harnessed in some places to clean up soil contaminated with heavy metals.

Answer 2

Systemic would be one way. Iron is often applied in this manner.