不同林龄马尾松针叶养分含量及其再吸收效率

以福建漳州南靖国有林场不同林龄马尾松为研究对象,探讨了马尾松养分含量及其内吸收的林龄效应。结果表明(:1)成熟针叶中,43a的马尾松针叶的平均N含量最高,而5a的则最低。马尾松成熟叶片的N含量表现出随树木年龄的增加而增加。5、10和20a的马尾松针叶P含量显著高于30和43a的树木(P0.05),P含量随着林分年龄的增长而逐渐下降,这与氮的趋势正好相反(。2)随着林分的生长,N含量呈现先下降后增加的趋势。5a的衰老针叶中P含量最高,而20a的最低。(3)43和30a马尾松树木叶片的N再吸收效率差异不明显,其再吸收效率都在65%左右,显著低于10a和20a的马尾松;叶片P的再吸收效率其随着林龄变化的规律与N的再吸收规律相似,除43a外,P的再吸收率均要小于氮的再吸收率。从总体上看,43a马尾松树木叶片对养分(N、P)的再吸收效率都显著低于其他4个年龄,而10、20a马尾松表现了最大的再吸收效率。

Nutrients and Their Resorption Efficiencies in Leaves of Pinus. massoniana of Different Ages

Research on Pinus massoniana in different ages of forest in forestry farm of Nanjing, Zhangzhou, Fujian, it explored to the effect on Pinus massoniana by ages of forest between nutrient content and internal absorption. The result indicates that, （ 1 ） The average N contents of Pinus, massom＇ana in 43 years stand was maximum and S years stand was minimum, which in mature leaves increased significantly during stand development. P contents ofPinus. Massoniana in 5,10,20 years stand were higher than those in 30 and 43 years stand（P〈0.05） obviously, while P contents were decreased with stand development. （ 2 ） Along with the growth of stands, the content of N assumed fall-rise trend, the content of P was the highest in the senile needles of five years old tree and reached the lowest in that of twenty years old. （ 3 ） There were no significant difference of the reabsorption rate of N between the 30 years old and 43 years oldPinus massoniana, which were about 65% and significant lower than that in ten years and twenty years old ones. The variance of the re-absorption rate of P in leaves which was lower than that of N except for 43 years stand tree was similar to the variance of N. Generally, the re-absorption rate of nutrients like N and P in leaves of 43 years old Pinus massoniana was significant lower than that of the other 4 age ones, whereas that of ten years and twenty years old Pinus massoniana reached the peak.