Dynamic simulation water storage of different parts in peach tree under drought stress

Abstract

The simulation of stored water in various parts of fruit trees under drought stress could be described in detail by the application of mathematical modeling. Under drought stress, tissue water storage provides information on water status, water demand pattern and water regulation capacity by each part of the tree. In the present study, the potted peach (Prunus persica (L.) Batsch) tree was used as the test material, and the water operation model of each part of the tree was constructed based on the resistance-capacitance (RC) model. By analyzing transpiration rate, water potential and stored water during a drying cycle, we found that the water potential in different organs of the potted peach trees were all decreased with the increase in transpiration rate but showing an opposite trend to the transpiration. In the daytime, the stored water flowed out from various tissues, and at night, the water runs into the tissues via root absorption. With the worsening of drought, the regulation capacity of tissue water storage kept decreasing. There was a big difference in the trend of water storage change among different parts. The difference also existed in the amount of tissue stored water entering the transpiration and the amount of water absorption at night among different parts. With an adequate soil water supply, the water storage change of trunk (including the main root) accounted for 42.3% of the total water storage change, followed by 20.6%, 15.4%, 15.3% and 6.7% by the root system, fruits, branches and leaves, respectively. This difference was a result of cooperative actions of both water storage resistance and capacity. Estimated the total of absorbed water of tissue at night were approximately 10% of the daily total transpiration, and it could go above 20% for severely dry soil.