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LI-600N

Porometer/ Fluorometer

For needles, narrow leaves, and grasses

The LI-600N Porometer/ Fluorometer is the only instrument specifically optimized to measure the stomatal conductance and chlorophyll fluorescence of a single needle, narrow leaf, or blade of grass.

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Leaf sizes

Width: 1-3.5 mm

Length: minimum 14.2 mm

Thickness: maximum 2.8 mm

Diagram showing the features of the LI-600N Porometer/Fluorometer

How it's different

The LI-600N is designed to quickly survey needles, narrow leaves, and grasses under ambient conditions.

Reaches stability in 5-15 seconds across a range of g_sw rates.
Utilizes user-configurable stability criteria.
Log a measurement with the press of a button.

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.

Figure 1. Survey measurements of well-watered (WW) or water-stressed (WS) single loblolly pine (Pinus taeda) needles. Each point is the mean (±SE) of four measurements on four different greenhouse-grown seedlings measured at growth irradiances of 150-200 µmol m^-2 s^-1 PPFD.

Figure 2. Autumn diurnal measurements of stomatal conductance (gsw) and quantum yield of PSII (PhiPS2) of Pinus mugo needles measured on a clear day using the LI-600N. The points are the means of 3 needles (±SE) on the same plant. Each measurement period was about a minute to collect the data.

Figure 3. A high-quality Multiphase Flash™ (MPF) measurement on a single blade of greenhouse-grown buffalograss (Bouteloua dactyloides) at ambient PPFD of 670 µmol m^-2 s^-1.