In this paper, nitrogen (N) and phosphorus (P) retranslocation during leaf senescence in 23 mangrove species (15 specific true-mangroves, 8 specific semi-mangroves)are studied. The results are as follows. (1)In contrast to semi-mangroves leaves, mature leaves of true-mangroves are relatively low nutrient (N and P) concentration expressed on a dry mass basis (Nmass and Pmass mg/g),with 17.3 mg/g for N and 1.4 mg/g for P respectively. N and P concentrations decrease with leaf senescence. (2) Leaf N/P ratios are in most instances ~31, suggesting N limitation. (3)N retransloeation efficiency (NRE) is average 63. 6 % in true-mangroves, which is greater than that in semi-mangroves (52. 2 %) or the general evergreen trees (47. 0%). But there are no significant differences of P retransloeation efficiency (PRE) between true-mangroves (53. 4%) and semi-mangroves (49.4%). This suggests that true-mangroves reliably have a high capability in nitrogen-conservation for some factors. And true-mangroves are physiologically adapted to live in lower N-supply environments.%研究了23种红树植物（15种真红树植物,8种半红树植物）叶片衰老过程中氮（N）、磷（P）内吸收率.结果表明：（1）真红树植物与半红树植物相比,其叶片营养元素含量相对较低（Nmass=17.3mg/g;Pmass=1.4mg/g）,N、P含量随叶片衰老而减少;（2）大部分红树植物叶片氮磷比小于31,说明红树植物存在氮限制;（3）真红树植物氮内吸收率平均为63.6%,远高于半红树植物（52.2%）以及一般常绿植物（47.0%）,但真红树植物磷内吸收（53.4%）和半红树植物（49.4%）不存在显著的差异.因此,真红树植物拥有更高的氮保存能力,使其更适应于在缺氮环境下生存.
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