Patterns of root respiration rates and morphological traits in 13 tree species in a tropical forest
Patterns of root respiration rates and morphological traits in 13 tree species in a tropical forest
复制标题
DOI：
10.1093/treephys/tps008
复制
发表时间：
2012-03-01
期刊：
影响因子：
4
通讯作者：
Nik, Abdul Rahim
中科院分区：
文献类型：
--
作者：
Makita, Naoki;Kosugi, Yoshiko;Nik, Abdul Rahim
林木根系是由直径不等、生理特性各异的根系组成的。然而，各种热带物种的细根和粗根的根呼吸速率模式仍然未知。为了阐明呼吸作用与根系形态特征的关系，我们研究了比根呼吸作用及其与不同直径的平均根直径（D）和根组织密度的关系（RTD;单位根体积的根质量; gcm（-3））和比根长（SRL;每单位根质量的根长; mg（-1））的细根之间和内部的13个物种的14棵树，从一个原始的热带雨林在Pasoh森林保护区在马来西亚半岛。粗根（2- 269 mm）的呼吸速率随D的降低而增加，说明不同树种的粗根呼吸与直径之间存在显著的相关性。基于粗根呼吸速率径向梯度的模型模拟了呼吸随直径的指数下降。细根（<2 mm）的呼吸速率比粗根的呼吸速率高，且变异性大。对于细根，各树种的平均呼吸速率随D的减小而增大。细根的呼吸速率随RTD的增加而显著下降，随SRL的增加而增加，这解释了13个物种的14个树木之间的呼吸变化的一个重要部分。我们的研究结果表明，粗根呼吸在树种遵循的基本关系与D跨物种和细根呼吸的物种之间的变化大部分是由D，RTD和SRL解释。我们发现，根呼吸和形态性状之间的关系提供了一个定量的基础，从粗根细根和模式，在不同的物种。
The root systems of forest trees are composed of different diameters and heterogeneous physiological traits. However, the pattern of root respiration rates from finer and coarser roots across various tropical species remains unknown. To clarify how respiration is related to the morphological traits of roots, we evaluated specific root respiration and its relationships to mean root diameter (D) of various diameter and root tissue density (RTD; root mass per unit root volume; gcm(-3)) and specific root length (SRL; root length per unit root mass; mg(-1)) of the fine roots among and within 14 trees of 13 species from a primary tropical rainforest in the Pasoh Forest Reserve in Peninsular Malaysia. Coarse root (2-269mm) respiration rates increased with decreasing D, resulting in significant relationships between root respiration and diameter across species. A model based on a radial gradient of respiration rates of coarse roots simulated the exponential decrease in respiration with diameter. The respiration rate of fine roots (< 2mm) was much higher and more variable than those of larger diameter roots. For fine roots, the mean respiration rates for each species increased with decreasing D. The respiration rates of fine roots declined markedly with increasing RTD and increased with increasing SRL, which explained a significant portion of the variation in the respiration among the 14 trees from 13 species examined. Our results indicate that coarse root respiration in tree species follows a basic relationship with D across species and that most of the variation in fine root respiration among species is explained by D, RTD and SRL. We found that the relationship between root respiration and morphological traits provides a quantitative basis for separating fine roots from coarse roots and that the pattern holds across different species.