Abstract: We measured the sap flow of Prunus armeniacaL. in Turpan Basin, using the PS-TDP8 pintype thermal diffusion probe technology, and recorded the meteorological factors of the orchard synchronously, with the aim to establish the relationship between sap flow and environmental factors. Results from this study can provide a basis for efficient and water saving cultivation of P. armeniaca in arid areas. The results showed that sap flow rate of P. armeniaca showed obvious diurnal variation. The peak value of sap flow rate occurred in June and July, being 0.71 and 0.78 g·s^-1, respectively. The sap flow rate was higher on a sunny day than on a cloudy day, and the start-up time of sap flow on a sunny day was 1 h earlier than that on a cloudy day. The starting time of sap flow in summer was around 07:30-08:00, which was 1 h earlier than that of spring and autumn, with a long duration and large flow amount per unit time. Such changes caused the average unit time sap flow, daily average sap flow, and monthly sap flow of P. armeniaca being the largest in summer, which were 0.461 L·h^-1, 11.062 L·d^-1, and 331.68 L·month^-1, respectively. The variations of air temperature, solar radiation, and water pressure deficit were basically consistent with the variations of sap flow rate, with a significant positive correlation between them (P<0.01). The variations of relative humidity were negatively correlated with the diurnal variations of sap flow rate (P<0.01). Stepwise regression models between stem sap flow rate and environmental factors were established. The model well fit the relationship between sap flow rate of P. armeniaca and environmental factors, with the coefficient of determination (R²) in each month was larger than 0.85 in the regression model. To sum up, the sap flow rate of P. armeniaca was quickened and transpirational water consumption was increased by strong solar radiation and high temperature in summer. Therefore, we should increase the irrigation frequency in summer days. The irrigation time should be selected before sunrise or after sunset to reduce water loss due to evaporation.

Key words: Prunus armeniacaL., sap flow, environmental factor, Turpan Basin.