What are metal-loving plants? Is this a description that involves intimate relationships with tin foil? Not exactly, but not so far off either. I call them metal-loving because these plants' tissues absorb large amounts of metal from the soil--metals like zinc, iron, copper, and selenium. Different plants absorb different metals. By large amounts I mean that some of them collect one hundred times the metal that other plants accumulate.
Large amounts of metals can be toxic; in fact, scientists think that the plants accumulate the metals as means to defend themselves against insect predators. The plants are so concentrated with metal that insects will avoid snacking on them. These plants protect themselves, though, by storing the metals in microscopic containers that are surrounded by a membrane that protects the rest of the plant.
Many of these same metals are also crucial to the human body's everyday functioning. Insufficient amounts of them can lead to malnutrition and disease. Thus enter metal-loving plants. Scientists have identified and cloned the metal-absorbing genes in some of these plants in hopes of introducing them to crop plants. In other words, they want to take plants we already eat and turn them into metal-loving plants that we can use as metal supplements. Scientists are particularly interested in plants that accumulate the metal selenium, which is known to be a potent anti-carcinogen.
Besides being useful to human health, though, these metal-loving plants might also be good for the environment. Scientists hope to use them to clean up industrial lands contaminated by heavy metals and/or radioactive material.