Measuring Stomatal Conductance with FLIR Lepton Thermal Arrays
How non-invasive radiometric thermal imaging explores stomatal transpiration changes before visual symptoms appear in tropical houseplants.
The Physics of Stomatal Transpiration
Plants exchange water vapor and carbon dioxide through microscopic leaf pores called stomata. When a plant photosynthesizes under optimal atmospheric conditions, continuous evaporative cooling lowers the leaf surface temperature relative to ambient room air by 1.5°C to 3.2°C.
When root water uptake declines or vapor pressure deficit (VPD) rises above tolerable thresholds, guard cells lose turgor pressure, forcing stomata to seal tight to prevent desiccation. This stomatal closure halts evaporative cooling, causing the leaf surface temperature to immediately spike toward or above ambient room temperature.
Micro-Radiometric Thermal Arrays in NIH-01 Concept
Traditional soil moisture probes measure electrical conductivity in substrate surrounding roots, missing local root hair hypoxia, soil channeling, or VPD-induced transpiration stress. The FLIR Lepton 3.5 sensor array target in NIH-01 measures true leaf surface radiant thermal energy at 160x120 thermal pixel resolution.
By evaluating spatial thermal patterns across leaf laminae at regular intervals, the NIH-01 edge processor investigates subtle thermal changes indicative of early transpiration shutdown—giving plant owners early insight before physical leaf drooping or tip browning occurs.