The characteristics of apple tree transpiration rate and its influencing factors on the loess tableland region

This paper reported the experimental results of apple tree transpiration rate measured by TDP mainly in the growing seasons on the Loess Plateau,and the influencing factors to transpiration rate was also analyzed.The results showed that: the change of transpiration rate in clear day was in a form of single-peak curve;the diurnal change of transpiration rate was characterized by an upsurge and followed by a plummet.The transpiration rate,at night,was near 0 g/h,while it changed from 300 g/h to 1 000 g/h in the day time.June,July and August were the main periods for transpiration water consumption.In July,the amounts of daily transpiration reached to 3 038 g/d.Associated with the growth phase of apple trees,the maximum daily transpiration amounts appeared in the fruit expanding process stage,then the growing stages of shoots and young fruit in the autumn.In the experimental period,the transpiration rate of apple trees increased with the increasing of global solar radiation and atmospheric temperature.