To analyze the tradeoff relationship between twigs and leaves, the traits of Pinus hwang-shanensis including leaf area, leaf number, twig length and twig diameter were investigated in Wuyi Mountains along an altitudinal gradient. The results indicated that leaf number, twig length, twig diameter, leafing intensity and twig stem cross-sectional area of P. hwangshanensis increased gra-dually with the increasing altitude, while individual leaf area decreased gradually. Leafing intensity of P. hwangshanensis at different altitudes had significant negative relationships with leaf area. The cross-sectional area of P. hwangshanensis had significant positive relationship with total leaf area. Twig length and twig diameter of P. hwangshanensis correlated negatively with leafing intensity, but positively with leaf area, leaf number and total leaf area. To enhance the competitiveness and resource utilization efficiency, P. hwangshanensis at low altitude tended to have relatively few large leaves on short twigs, and those at high altitude tended to have a large number of small leaves on long twigs. Such tradeoff between twigs and leaves reflected the strategy of resource utilization and the balance of biomass allocation mechanism of P. hwangshanensis responding to the altitudinal change.
对武夷山自然保护区不同海拔黄山松叶片面积、叶片数量、小枝长度及小枝直径等性状进行测定,分析不同海拔黄山松枝-叶大小间的权衡关系.结果表明: 随海拔升高,黄山松小枝的叶片数量、小枝长度、小枝直径、出叶强度及茎截面积逐渐增大,单叶面积呈逐渐减小趋势;不同海拔黄山松小枝出叶强度与单叶面积均呈显著负相关,不同海拔黄山松小枝茎截面积与总叶面积呈显著正相关;不同海拔黄山松小枝长度、小枝直径与出叶强度呈显著负相关,与单叶面积、叶片数量及总叶面积均呈显著正相关.为提高竞争优势或是资源利用效率,低海拔黄山松倾向于在短枝上着生量少但单叶面积大的针叶,而高海拔黄山松趋向于在长枝上着生量大但单叶面积小的针叶,这体现出不同海拔梯度黄山松小枝的资源利用策略及枝叶间生物量分配的权衡机制.
Keywords: leaf area; leaf number; leafing intensity; twig diameter; twig length.