An improved cuvette for individual evaluations of gas exchange parameters on adaxial and abaxial leaf surfaces under different air currents

For individual evaluations of gas exchange parameters on adaxial and abaxial leaf surfaces, the Parkinson leaf cuvette (PP Systems. Ltd., UK) was improved by providing individual air paths to the respective upper (adaxial) and lower (abaxial) leaf cuvettes, where air current in each cuvette was also adjustable independently. The performance of the improved cuvette system was examined by using a wetted filter paper and a cucumber leaf. The three different modes of measurement, i.e. the upper cuvette mode, the lower cuvette mode and the both cuvettes mode, were selected successively, and leaf boundary layer conductance on each surface was arbitrarily adjusted in the range of 0.3 mol m^<-2>s^<-1> to 1.0 mol m^<-2>s^<-1>. The heterogeneity between adaxial and abaxial surfaces of the cucumber leaf was found in gas exchange parameters such as stomatal conductance and rates of transpiration and photosynthesis, and further stomatal response to air current was revealed quantitatively by change in stomatal conductance.