Research investigates the chemical nanostructure of water conducting vessels.
Plant cells are encased in a structure called the cell wall, composed mainly of cellulose and lignin. Among other functions, this wall gives structural stability to the cells and controls the entry of water, minerals and other substances. When they die, the cells leave behind their cell wall, forming different structures that support the plant giving rigidity to the stems and that facilitate the transport of substances from the roots to the leaves and vice versa. One such structure is the xylem: a continuous network of conduits about 100 micrometers in diameter that carries the water absorbed by the roots to the leaves.
When they lose water by transpiration, the leaves generate tension in the water column within the xylem. The pressure difference between the interior and exterior of the conduit causes the molecules to behave as links in a current: when a molecule of water evaporates, the rest of the “current” is pulled up.
Image: Schematic figure of the technique of infrared nanospectroscopy.