A canopy porometer for photosynthesis studies in field crops

A portable, modular porometer for whole-plant or canopy photosynthetic and respiratory gas exchange estimation is described. The system features within-chamber light and temperature measurement and in its present configuration permits analysis of carbon dioxide and water vapour exchange by an extension of the syringe-based "CO2 depletion" technique. Operating characteristics of the system and potential modifications are discussed, along with limitations and applications.