Leaf photosynthetic traits scale with hydraulic conductivity and wood density in Panamanian forest canopy trees
Leaf photosynthetic traits scale with hydraulic conductivity and wood density in Panamanian forest canopy trees
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DOI：
10.1007/s00442-004-1624-1
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发表时间：
2004-07
期刊：
影响因子：
2.7
通讯作者：
Louis S. Santiago;Louis S. Santiago;Guillermo Goldstein;F. Meinzer;Jack B. Fisher;K. Machado;D. Woo
中科院分区：
文献类型：
--
作者：
Louis S. Santiago;Louis S. Santiago;Guillermo Goldstein;F. Meinzer;Jack B. Fisher;K. Machado;D. Woo
我们调查了水的运输能力，木材密度和木材解剖学相关的叶片光合特性在巴拿马的两个低地森林。在20种冠层乔木中，上部枝的叶片比导水率（kL）与单位叶面积CO2净同化率（Aarea）和气孔导度（gs）的最大值呈正相关。MaximumkL与Aarea的相关性比initialL强，说明光合势分配与最大水分运输能力成正比。顶枝kL与Aarea/g呈负相关，与单位氮光合作用呈正相关，表明水分运输效率不同，光合作用中水分利用效率与氮利用效率存在权衡关系。由木质部解剖特征计算的比导水率（ktheoretical）与Aarea和kL呈正相关，与生理测量值之间的关系一致。分支材密度与木材饱和储水量、kL、Aarea、单位叶质量净CO2同化量（Amass）和覆盖叶上测得的最小叶水势呈负相关，表明木材密度将生理功能限制在特定的操作范围内。因此，分支水运输能力的动态和静态指数表现出相当大的协调与分配潜在的碳收益。我们的研究结果表明，了解树的水力结构提供了更多的见解，比较物种之间的叶水平测量，并链接光合分配模式与分支水力过程。
We investigated how water transport capacity, wood density and wood anatomy were related to leaf photosynthetic traits in two lowland forests in Panama. Leaf-specific hydraulic conductivity (kL) of upper branches was positively correlated with maximum rates of net CO2assimilation per unit leaf area (Aarea) and stomatal conductance (gs) across 20 species of canopy trees. MaximumkLshowed stronger correlation withAareathan initialkLsuggesting that allocation to photosynthetic potential is proportional to maximum water transport capacity. Terminal branchkLwas negatively correlated withAarea/gsand positively correlated with photosynthesis per unit N, indicating a trade-off of efficient use of water against efficient use of N in photosynthesis as water transport efficiency varied. Specific hydraulic conductivity calculated from xylem anatomical characteristics (ktheoretical) was positively related toAareaandkL, consistent with relationships among physiological measurements. Branch wood density was negatively correlated with wood water storage at saturation,kL,Aarea, net CO2assimilation per unit leaf mass (Amass), and minimum leaf water potential measured on covered leaves, suggesting that wood density constrains physiological function to specific operating ranges. Kinetic and static indices of branch water transport capacity thus exhibit considerable co-ordination with allocation to potential carbon gain. Our results indicate that understanding tree hydraulic architecture provides added insights to comparisons of leaf level measurements among species, and links photosynthetic allocation patterns with branch hydraulic processes.