Stomatal response and photosynthetic capacity of maize leaves at low temperature. A study on varietal differences in chilling sensitivity

The impairment of the turgor operated modulation of stomatal movement and changes in photosynthetic capacity were studied using two maize (Zea mays L.) varieties of different chilling sensitivity. In the tolerant variety stomatal opening exhibited characteristic transients, while in the more susceptible strain chilling induced a monotonous increase of stomatal apertures. Photosynthetic capacity of the leaves (expressed in terms of 14CO2 incorporation at 25°C) declined as a result of chilling regardless of stomatal opening. Nevertheless, tolerance was reflected in the preservation of a higher level of CO2 fixation capacity and in a more successful recovery.