7.1 How the Leaf Porometer Works
The Leaf Porometer measures the stomatal conductance of leaves by
putting the conductance of the leaf in series with two known conductance
elements. By measuring the humidity difference across one
of the known conductance elements, the water vapor flux is known.
The conductance of the leaf can be calculated from these variables.
We know the humidity at three places: inside the leaf, and at both of
the humidity sensors. The Leaf Porometer effectively calculates the
resistance between the inside and outside of the leaf: the stomatal
conductance. It measures resistance between the leaf and the first
humidity sensor and the first and second sensors. The Leaf Porometer
Function diagram represents these measurement process.