Fig. 1.

Schematic diagram of the system used to image whole plants for chlorophyll a fluorescence and temperature under controlled conditions. The imaging system was modified to allow the attachment of two cameras, the thermal camera being directly positioned above the plant and the fluorescence camera situated at 90 ° to the thermal camera, utilizing a silver-backed mirror at 45 ° to capture images of F _q′/F _m′. The plant was positioned within an open-topped chamber (photograph insert) where concentrations of O₂, CO₂, and H₂O were maintained at a typical flow rate of ~0.87 l s^–1 N₂, with all gases passing through a humidifying system prior to entering the chamber. Concentrations of O₂, CO₂, and H₂O were measured every second by an IRGA and oxygen sensor.