The relative contribution of low soil and air temperatures towards the overall inhibition of hotosynthesis in soybean is still unclear. The mechanisms involved in the dark chilling-induced inhibition ofphotosynthesis were explored further in a chilling tolerant (Highveld Top) and ensitive (PAN809) soybean genotype in experiments where low soil temperatures were present (whole plant chilling, WPC) or absent (shoot-localised chilling, SC). Initially (after three nights of chilling) both the WPC and SC treatments induced the same symptoms in PAN809. These symptoms could thus be ascribed to chilling stress effects on the shoots. Typical symptoms included reduced CO2 assimilation capacity, inhibition of photosystem II function and lower chloroplast fructose-1,6-bisphosphatase (cFBPase) and ucrosephosphate-synthase (SPS) activity. When the nodulated root systems of PAN809 were also exposed to lowtemperatures (WPC treatment), additional constraints gradually developed, which were not observed inHighveld Top. Novel evidence is provided showing that the response in PAN809 is influenced by whether whole-plant or shoot-localised dark chilling occurs and that cFBPase is specifically targeted resulting insevere inhibition of CO2 assimilation capacity.