How it works

The LI-600N brings together numerous innovative technologies to deliver fast, accurate, and dependable measurements in a compact, handheld device.

Stomatal conductance

The LI-600N uses an open flow-through differential measurement for quantifying transpiration (E) and stomatal conductance around the needle or narrow leaf. First, E is quantified by measuring the flow rate and water vapor mole fraction of air that enters and leaves the chamber. Meanwhile, total conductance to water vapor (g_tw) is computed as a function of E and vapor pressure in the leaf and cuvette. Finally, stomatal conductance to water (g_sw) is computed as a function of g_tw and the boundary layer conductance to water vapor (g_bw).

The advantages of the LI-600N measurement flow path include the following:

• Flow rates quickly flush through the small chamber volume and result in rapid stabilization for quick measurements
• A differential measurement in close to ambient conditions
• Minimally disturbed light, CO₂, and H₂O during the measurement eliminate the need for desiccant chambers or corrections for large diffusion gradients
• Automatic matching accounts for drift between the reference and sample sensors

High accuracy at low conductance

Get high-quality, accurate measurements from single needles and blades of grass, even at extremely low conductance.