Warren C R, Adams M A
Department of Botany, University of Western Australia, Nedlands, WA 6907, Australia e-mail:
Oecologia. 2000 Sep;124(4):487-494. doi: 10.1007/PL00008874.
We investigated interspecific variation in leaf lifespan (persistence) and consequent differences in leaf biochemistry, anatomy, morphology, patterns of whole-tree carbon allocation and stand productivity. We tested the hypothesis that a species with short-lived foliage, Pinus radiata D. Don (mean leaf lifespan 2.5 years), grows faster than P. pinaster Ait., a species with more persistent foliage (leaf lifespan 5.6 years), and that the faster growth rate of P. radiata is associated with a greater allocation of nitrogen and carbon to photosynthetic tissues across a range of scales. In fully sunlit foliage, the proportion of leaf N in the major photosynthetic enzyme Rubisco (ribulose-1, 5-bisphosphate carboxylase) was greater in P. radiata than in P. pinaster, and, in mid-canopy foliage, the proportion of leaf N in thylakoid proteins was greater in P. radiata. A lesser proportion of needle cross-sectional area was occupied by structural tissue in P. radiata compared to P. pinaster. Foliage mass in stands of P. radiata was 9.7 t ha compared with 18.2 t ha in P. pinaster while leaf area index of both species was similar at 4.6 m m, owing to the compensating effect of differences in specific leaf area. Hence trade-offs between persistence and productivity were apparent as interspecific differences in patterns of whole-tree carbon allocation, needle morphology, anatomy and biochemistry. However, these interspecific differences did not translate into differences at the stand scale since rates of biomass accumulation were similar in both species (P. radiata 6.9±0.9 kg year tree; P. pinaster 7.4±0.9 kg year tree). The similarities in performance at larger scales suggest that leaf area index (and radiation interception) determines growth and productivity.
我们研究了叶寿命（持久性）的种间差异以及由此导致的叶片生物化学、解剖结构、形态、整株树碳分配模式和林分生产力的差异。我们检验了以下假设：叶寿命较短的辐射松（Pinus radiata D. Don，平均叶寿命2.5年）比叶寿命更长（叶寿命5.6年）的海岸松（P. pinaster Ait.）生长更快，并且辐射松较快的生长速率与在一系列尺度上向光合组织分配更多的氮和碳有关。在完全光照的叶片中，主要光合酶核酮糖-1,5-二磷酸羧化酶（Rubisco）中叶片氮的比例在辐射松中比在海岸松中更高，并且在树冠中部的叶片中，类囊体蛋白中叶片氮的比例在辐射松中更高。与海岸松相比，辐射松针叶横截面积中被结构组织占据的比例较小。辐射松林分中的叶量为9.7吨/公顷，而海岸松为18.2吨/公顷，同时由于比叶面积差异的补偿作用，两个物种的叶面积指数相似，均为4.6平方米/平方米。因此，持久性和生产力之间的权衡在整株树碳分配模式、针叶形态、解剖结构和生物化学的种间差异中很明显。然而，这些种间差异并没有转化为林分尺度上的差异，因为两个物种的生物量积累速率相似（辐射松6.9±0.9千克/年·株；海岸松7.4±0.9千克/年·株）。在较大尺度上表现的相似性表明叶面积指数（以及辐射截获）决定了生长和生产力。
