中文摘要：

为了解根外追肥对常绿阔叶树种养分再吸收的影响,以7.5年生刨花楠（Machilus pauhoi,MP）人工林为研究对象,设置不同的氮（N）、磷（P）梯度对叶片进行根外追肥,并分别于6月、9月、12月对成熟新叶与衰老叶进行采样,测定其N、P含量,计算其N、P再吸收效率;采用双因素方差分析法分析不同喷施处理与不同季节对刨花楠叶片N、P再吸收效率的影响.结果表明：（1）除低N且N、P配施与中N且N、P配施处理外,其余N、P喷施处理对刨花楠叶片N、P再吸收效率有显著影响（P〈0.05）;同一处理组内刨花楠在不同季节,其叶片N、P再吸收效率也存在显著差异（P〈0.05）（单施P除外）;（2）生长旺季时叶面喷施N肥能够促进叶片对P元素的吸收,叶面喷施P肥能够促进叶片对N元素的吸收;N、P再吸收效率之间呈显著正相关（P〈0.05）;（3）叶片在衰老过程中存在明显的N再吸收现象.可见不同喷施处理对于不同季节的叶片N、P再吸收效率的影响机制不同.本研究结果可为探讨亚热带珍稀常绿阔叶树种养分循环利用以及贫瘠立地环境植物养分保存机制等提供理论依据.表3参40

英文摘要：

For a comprehensive understanding of the nutrient conservation mechanism of Machilus patlhoi in subtropicalzone, we need to know the response of leaf nutrient resorption efficiency to the environment and fertilizer. This research aimed to study the variation of leaf nutrient resorption efficiency with nitrogen and phosphorus spraying in different seasons. A 7.5-year-old M, pauhoi plantation in Fujian Province was taken as research object. Different levels of N and P were set by tbliage top-dressing to the plantation. Samples were taken to determine their nutrient contents in June, September and December. Two-factor Variance Analysis was used to analyze the effect of the seasons and N, P spraying on the leaf nutrient resorption efficiency. The results showed that 1） different levels of N, P spraying had significant effects on leaf N, P resorption efficiency except for the low level N with N/P combined addition, and the medium level N with N/P combined addition; there were significant differences in N and P resorption efficiency of different seasons under different levels of fertilization （except for P addition. 2） N spraying could help vegetation to absorb P efficiently, and vise versa, in growing season; there was a positive relation between the resorption efficiency of N and P. 3） In mature leaves N resorption efficiency was positively related to N content, but in senesced leaves N resorption efficiency was negatively related to N content. An obvious N, P resorption phenomenon existed in M. pauhoi leaves in the process of senescing. The N and P resorption efficiency showed significant differences responding to fertilization and seasons. This research added our knowledge about the nutrient conservation qlechanism of evergreen broad-leaved forest in subtropical zone.