CO2assimilation rate of a ‘Hayward’ kiwifruit(Actinidia deliciosa(A. Chev.) C.F. Liang et A.R. Ferguson) adult vine was measured during the summer of 1989 by two methods. One, an open‐system chamber enclosing a whole vine canopy, was designed for continuous investigation of photosynthesis via the monitoring of external light, humidity, air flow, and air CO2concentration. The other was the ADC‐LCA1 system, which sampled only a part of a single leaf. The results indicate that photosynthesis rate value increases with light intensity in both instances, but, with respect to the single‐leaf CO2measurements, the whole canopy CO2exchange measurement shows lower variability. Also absolute values for single leaf photosynthesis are higher than those observed for the whole plant.