Under no water deficit,the sap flow of Juglans mandshurica is affected by microclimatic factors,especially the relative humidity,air temperature and solar radiation.The diurnal pattern of sap flow rate of Juglans mandshurica is similar with that of air temperature and relative humidity. Juglans mandshurica has several sap flow rate peaks with the maximums value of 1600g/h,occurring at 15:00.At the night time,the flow still happens,indicating that the root pressure of Juglans mandshurica functions...