Dead pipes can still regulate plants’ water

In a new twist on zombie botany, Harvard University physiologists have found that the pipes in a plant’s water plumbing can regulate the flow speed, despite the disability of being dead.

Round spots (lower left), which contain a pectin hydrogel, change porosity when ion concentrations vary in the water flowing through. Zwieniecki

The stack of dead cells, called xylem vessel members, respond to what’s in the water whipping through, report Maciej A. Zwieniecki and his colleagues. When the cells carry high concentrations of calcium, potassium, or other ions, the researchers say, membranes between cells become more porous, speeding the stream.