Photosynthesis in Sitka Spruce (Picea sitchensis (Bong.) Carr.) VI. Response of stomata to temperature.
The experimental material (all of Queen Charlotte Islands provenance) consisted of seedlings grown for three months in growth chambers and detached shoots taken from the S.-facing side of a forest road in Aberdeen, Scotland. The steady-state stomatal conductance (ks) of illuminated needles was found to be at a maximum with temperatures of 5-15 deg C in summer and 0-10 deg C in winter, partly as a result of higher leaf/air vapour-pressure differences outside this range; it was also influenced by the previous temperature regime. Possible mechanisms by which temperature can influence ks are discussed.