Abstract:The responses of hydraulic transport efficiency and safety to nutrients and water addition are the foundation for probing the mechanisms of extensive acclimation in Pinus tabulaeformis. Using the newlydeveloped centrifuge method and taking three treatments as control (CK, no fertilization, natural precipitation), N and P addition (F, fertilizers were applied with the application rate as 120 kg/hm2 pure N and 60 kg/hm2 pure P per year, natural precipitation), N and P addition plus irrigation (FI, fertilizers were applied with the application rate as 120 kg/hm2 pure N and 60 kg/hm2 pure P per year, 100 mm water was irrigated excluding local precipitation), we studied the responses of transport efficiency and vulnerability to embolism of currentyear stems in Chinese pine seedlings to nutrients and water addition. The results indicated that: (1) N and P addition raised basal diameter, canopy size and aboveground biomass, but had no effect on specific hydraulic conductivity (Ks), leaf specific conductivity (LSC), Huber value, embolism resistance (P50) and safety margin comparing to the control. (2) Concurrent addition of N, P and water increased plant height, basal diameter, canopy size and aboveground biomass, no difference between treatments was found for Ks, LSC and Huber value, but P50 of FI treatment increased by 0.2 MPa and safety margin also narrowed. These results suggest that nutrient addition had no obvious effect on transport efficiency and safety; water addition did not affect transport efficiency but increased the vulnerability to embolism. The reason was mainly related with longer tracheid length and lower implosion resistance in FI treatment.