The Leaf Porometer is a battery-operated, menu-driven device that
measures stomatal conductance of leaves. Stomatal conductance is a
function of the density, size, and degree of opening, of stomata, which
are pores in plants that open to the outside air. The Leaf Porometer
measures stomatal conductance by putting the conductance of a leaf
in series with two known conductance elements, and comparing the
humidity measurements between them. It can display information in three selectable units: