How do plants excrete?
Do living vegetables or, to put it more broadly, living plants excrete? Not necessarily in the sense that animals do. But like all other organisms they process certain inputs and produce certain outputs, some of which we may characterize as waste. Figuring out where the waste went puzzled some early naturalists. In the late 18th century, the pioneering naturalist Erasmus Darwin (grandfather of Charles) wrote, “Others have believed [the leaves to be] excretory organs of excrementitious juices, but as the vapor exhaled from vegetables has no taste, this idea is [not] probable.” But there may be something to the notion that leaves perform an excretory function, as we shall see. Eventually biologists learned that plant cells have internal sacs called vacuoles that are used for storage, and that a lot of what gets stored is waste–vacuoles can account for as much as 90 percent of cell volume in a mature plant. But the waste is being stored on site, so to speak. Some scientists claim that he
