Abstract:Studies on the response of stomatal resistance of plants to fertilization under dryland conditions can provide important insight as to the regulation of water use by means of soil fertility management. During the growing season, we measured the stomatal resistance on both sides of the winter wheat leaves with Li-1600 Steady State Porometer at different fertilization levels. The application of N and P fertilizers (Urea, Calcium superphosphate and rapeseed cake) decreased the leaf water potential of winter wheat Fertilization resulted in apparently different responses of abaxial and adaxial stomata1 resistance to the changes of environmental factors when there was a water deficit in crop plants. The abaxial stomatal resistance was more responsive to fertilization than adaxial stomatal resistance. The abaxial stomatal resistance increased more rapidly and to a larger extent than adaxial stomatal resistance with increasing fertilization levels. Both abaxial and adaxial stomatal resistances increased sharply in an immediate response to fertilization. After that, there was a slow but linear increase of stomatal resistances with the increase of fertilization levels. Our results also showed that the ratio of abaxial to adaxial stomatal resistance (Rab/Rad) increased linearly with increasing fertilizer-application levels, regardless of the water potentials that were greatly affected by fertilization. We concluded that, under dryland conditions,fertilization had effect on the improvement of the sensitivity of abaxial stomatal resistance to the changes of environmental factors.