The AP4 automatic foliar evapotranspiration meter (porometer) directly measures stomatal conductance or stomatal resistance. Simple absolute field calibration reduces leaf stress during measurement. Ideal for phenotyping-based studies, the AP4 features an award-winning user interface and is backed by a 5-year warranty.

Stomatal opening is a key determinant of leaf surface diffusive conductance, which controls water loss from plant leaves and CO2 uptake for photosynthesis. Therefore, measurements of diffusive conductance are important indicators of plant water status and provide valuable insights into plant growth and adaptation to environmental changes.

AP4 Leaf Porometer Features The AP4 Leaf Porometer measures diffusion conductivity by comparing the exact wetting rate in a small chamber with the readings of a calibration plate. The plate has 6 diffusion conductivity settings, the values of which have been precisely determined by finite element analysis.

The accuracy figures quoted for other porometers and gas analysis systems are based on lengthy laboratory setup and calibration that bears little resemblance to field conditions. In contrast, the AP4 Leaf Porometer features a simple direct field calibration against a verified physical standard.

The AP4 Leaf Porometer has a number of other features designed to ensure that accurate, repeatable measurements are made as easily as possible: