Intracellular Landfills
(Apple and orange as props)
My message is very straightforward - it should take me only a minute. When you bite into an apple or drink the juice from an orange most of what you get is vacuolar sap. Plant vacuoles represent more than 50% of
total cell volume - they are major intracellular warehouses for the good stuff. That's one side of the equation. The other side is the part the vacuole plays in protecting the plant from the bad stuff - its own toxic waste, and the waste of others, ourselves included. In the US, alone, there are some 40,000 uncontrolled waste sites - land polluted with heavy metals, such as mercury, arsenic and cadmium, that will have to be cleaned up. The traditional approach to soil remediation is very simple...to dig it up and stockpile it elsewhere. However, despite its simplicity, this option is prohibitively expensive - $1-2 million per acre! Hence the urgent need for technologies based on phytoremediation - the use of native or engineered plant species for the unobtrusive, aesthetically appealing, inexpensive, extraction and accumulation of pollutants. But if this is to work for heavy metals that cannot be made into something else, cannot be metabolized, advantage will have to be taken of the fact that plants not only deploy the vacuole as a warehouse but also as a high capacity intracellular landfill for the sequestration of materials that would otherwise poison the thing that's doing the cleaning up - the plant itself.