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CNN Live Saturday

Scientists Identify a Plant Whose Genes Help Clean Up Polluted Industrial Sites

Aired August 18, 2001 - 12:20   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
DONNA KELLEY, CNN ANCHOR: We turn to a powerful plant, its genes could enable scientists to engineer plants that clean up polluted industrial sites or add essential micronutrients to food.

Scientists at Purdue University have identified and cloned the genes. And joining us live from Purdue University is David Salt. He's professor of plant molecular physiology. And he is the principal investigator of the project.

Professor Salt, hi.

DAVID SALT, PURDUE UNIVERSITY: Good morning.

KELLEY: You know, it's interesting to me. Tell us a little bit. This is some plant that grows just in the Austrian Alps. Tell us a little bit more about this and how you found it?

SALT: Sure, this is actually a group of -- one of a group of plants called metal hyperaccumulators. And these plants are extraordinary in the fact they're able to accumulate from their natural environments extremely high levels of certain metals, particularly nickel and zinc.

And when I say high, I'm talking about 1,000 times more than most other plants, about 1 percent of their dry weight.

KELLEY: And what's the theory on this plant, why it does it?

SALT: Well, there's been some thought and some experiments. And the general opinion I think is that this is basically a feeding deterrent. And what I mean by that is if you're a bug and you're creeping around on this plant, and you jump into it, it's going to taste pretty terrible. And so it's going to basically deter insects from feeding on the plant, which obviously is a good thing for the plant.

KELLEY: So now, what do you want to take this plant and do with it? What do you think the applications for it are?

SALT: OK, what we are hopeful about is this idea to develop a plant which we can actually plant on a polluted site and actually use the plant to draw out the metal from the soil, accumulate it in the plant. We can harvest the plant, remove the plant from the site, thereby leaving a clean soil behind.

KELLEY: Have you tried it at any sites?

SALT: It's been tested over a number of years. This is certainly not an idea that I just came up with yesterday. The problem is being in the past, there are certain limiting factors, which we're trying to overcome. And I think that recent discoveries are certainly putting on us on road to getting this work now.

KELLEY: But what were limiting factors then? And what discoveries did you find? It was a slow-growing plant I think I read. And so now, you've speeded that up as well?

SALT: Well, OK, the basic problem is that we know this plant exists in nature. The trouble is it's a very small, slow growing plant. So even though it contains these large amounts of metal, the total amount of metal that can be removed is limited.

So what we hope to do is with these genes that we've cloned, to move those genes into a plant which we know can grow rapidly and to a large size, thereby maximizing the amount of metal we hope to take up from the soil.

KELLEY: In the experiments that you've done so far then, can you tell us how much it's soaked up when you put in maybe some of these toxic places?

SALT: So right now, we haven't done any field trials. We're still waiting to go into the field. There are still more preliminary -- we're moving these genes into plants right now. So I would think in the next six months, we'll have plants that we can actually test out at least in soil in the greenhouse. And we should come up with some numbers by then.

KELLEY: OK. In addition to that, quickly if you can, what about food? And I know we talked about the bugs wouldn't like it because of the taste of metal, but could humans use this for food?

SALT: Right. Yes, well, it may seem kind of counterintuitive. And kind of cross the other side of the coin here. But one of the problems which has been termed the hidden hunger in the world is that a lot of staple foods like rice, soy beans, corn, etcetera, actually have been bred for yield and not for food quality.

So these plants are now turning out to be deficient in some essential metals like zinc and iron. And we hope to use these genes to help enhance the levels of these essential micronutrients in the food. We'd only make the food contain sufficient for human consumption. Obviously, these wouldn't contain the same amount of metal that we would use for remediation.

KELLEY: All right. We'll have to see what kind of salad we're having.

SALT: Absolutely.

KELLEY: Professor David Salt, associate professor at Purdue University. A pleasure to have you join us. Thank you very much.

SALT: Thank you very much.

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