The Sensitivity of Adaxial and Abaxial Stomatal Resistance in Wheat Leaf to Soil Water Stress

Stomata control the rate of water vapour and CO_2 transfer out of and into, respectively, plant leaf. The study of the sensitivity of ada- xial stomatal and abaxial stomatal resistance to soil water stress is a very important aspect of plant physiological response to changes of en- vironmental factors. During the growing sea- son we measured the sotmatal resistance on both sides of wheat leaf with MK-3 porometer at two plots watered at different levels. The results show that: 1. There are obvious differences between the responses of adaxial and abaxial stomatal resistance to changes of environmental factors when there is soil water deficit (Fig.2). 2. The abaxial stomatal resistance increases faster and to a larger extent than abaxial one with a decrease of soil water potential in root zon? (Fig.6). 3. The ratio of abaxial stomatal res- istance to adaxial stomatal resistance are cons tant when soil water potential in root zone is higher than -50 kPa, and increase linearly with decrease of soil water potential when it is low e? than -50 kPa (Fig.7).