Resorption Efficiencies of Nitrogen and Phosphorus of Leaves During Senescence for Two Growth Forms of Avicennia marina
- 生命科学－已发表论文 
对广西北海大冠沙两种生长型(矮型:成熟林树高<1.5 m;过渡型:成熟林树高1.5~2 m)的红树植物白骨壤(Av-icennia marina)成熟叶和衰老叶的N、P含量、N∶P比及内吸收率进行研究.结果表明:(1)两种生长型白骨壤成熟叶具有较高的N含量,分别为(20.45±1.10)mg/g和(22.25±1.12)mg/g;P含量分别为(1.42±0.03)mg/g和(1.31±0.03)mg/g;叶片衰老过程中,N、P含量明显下降;(2)叶片衰老过程中,N∶P有增加的趋势;两种生长型成熟叶的N∶P分别为14.41±0.85和16.97±0.86,显示两种生长型白骨壤均为N、P共同限制;(3)两种生长型白骨壤的N、P内吸收率在60%以上,内吸收率的高低与生长型没有明显关系.Nitrogen and phosphorus concentrations,N∶P ratio and nutrient resorption efficiency of leaves during senescence for two growth forms(a dwarf form with tree height of below 1.5 m,and a transition form with tree height from 1.5 m to 2 m at maturity) of Avicennia marina were studied at Daguansha,Beihai,Guangxi.The results showed as follows:(1)Mature leaves had the relatively high N concentration,with(20.45±1.10) mg/g for dwarf form and(22.25±1.12) mg/g for transition form;P concentration of mature leaves was(1.42±0.03) mg/g for dwarf form and(1.31±0.03) mg/g for transition form,respectively;N and P concentrations decreased with leaf senescence.(2) N∶P ratio increased with leaf senescence,N∶P ratio of two growth forms was 14.41 ± 0.85 and 16.97 ± 0.86,respectively.(3) Resorption efficiency of N or P was above 60%,and there was no significant effect of growth form on resorption efficiency.