中文摘要：

探讨油松水分传输效率和安全性对养分和水分添加的响应是揭示其适应性的基础。该试验采用新改进的离心机技术,以2年生油松幼苗当年生枝为材料,试验设置对照（CK,不施肥、自然降水）、氮磷养分添加（F,按每年120kg/hm^2纯N和60kg/hm^2纯P水平添加N和P素,自然降水）及养分和水分同时添加（FI,按每年120kg/hm^2纯N和60kg/hm^2纯P水平添加N素和P素,且补水100mm）3个处理,研究了油松幼苗水分传输效率和栓塞脆弱性对氮磷养分和水分添加的响应。结果表明：（1）与CK相比,氮磷养分添加（F）增加了油松幼苗地径、冠幅和地上部生物量,但对比导水率（Ks）、比叶导水率（LSC）、Huber值、抵抗栓塞能力（P50）及水分传输安全阈值均影响不大。（2）氮磷和水分同时添加处理（FI）的地径、株高、冠幅和地上部生物量显著高于CK和F处理,其Ks、LSC和Huber值与CK及F处理相比并无显著差异,但P（50）比CK和F处理增加0.2MPa左右,且水分传输安全阈值相对变小。研究表明,养分添加对油松幼苗当年生枝的水分传输效率和安全性影响不大,水分添加对水分传输效率亦无显著影响,但降低了水分传输的安全性,原因主要与管胞长度增加及管胞壁抗爆破阻力下降有关。

英文摘要：

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 120kg/hm^2 pure N and60kg/hm^2 pure P per year,natural precipitation）,N and P addition plus irrigation（FI,fertilizers were applied with the application rate as 120kg/hm^2 pure N and 60kg/hm^2 pure P per year,100 mm water was irrigated excluding local precipitation）,we studied the responses of transport efficiency and vulnerability toembolism of current-year 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（P（50））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,LSCand Huber value,but P（50） 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.