Correlation between relative growth rate and specific leaf area requires associations of specific leaf area with nitrogen absorption rate of roots
Correlation between relative growth rate and specific leaf area requires associations of specific leaf area with nitrogen absorption rate of roots
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DOI：
10.1111/j.1469-8137.2008.02476.x
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发表时间：
2008-01-01
期刊：
影响因子：
9.4
通讯作者：
Tateno, Masaki
中科院分区：
文献类型：
--
作者：
Osone, Yoko;Ishida, Atsushi;Tateno, Masaki
许多研究报道了比叶面积（SLA）与相对生长率（RGR）之间的密切关系。然而，从理论上讲，SLA本身对RGR的净正效应很小，因为SLA的任何增加都不可避免地导致另一个RGR成分——面积基叶片氮浓度（LNCa）的降低。我们假设SLA与RGR之间的相关性需要与根系比氮吸收率（SAR）相关联，从而抵消了SLA对LNCa的负面影响。以5棵树和6种草本植物为研究对象，在最优条件下生长，利用平衡生长假设模型分析SAR和RGR组分之间的关系。不同物种间的SLA差异为1.9倍。模拟预测，如果SAR与SLA无关，SLA的这种变化将导致LNCa沿SLA梯度下降47%，从而对RGR产生边际净正效应。在现实中，SAR与SLA呈正相关，呈现出3.9倍的变化，这在很大程度上弥补了SLA对LNCa的负面影响。因此，LNCa值在不同物种间几乎是恒定的，SLA-RGR呈正相关。这些结果强调了叶根相互作用在理解RGR种间差异中的重要性。
Close correlations between specific leaf area (SLA) and relative growth rate (RGR) have been reported in many studies. However, theoretically, SLA by itself has small net positive effect on RGR because any increase in SLA inevitably causes a decrease in area-based leaf nitrogen concentration (LNCa), another RGR component. It was hypothesized that, for a correlation between SLA and RGR, SLA needs to be associated with specific nitrogen absorption rate of roots (SAR), which counteracts the negative effect of SLA on LNCa.Five trees and six herbs were grown under optimal conditions and relationships between SAR and RGR components were analyzed using a model based on balanced growth hypothesis.SLA varied 1.9-fold between species. Simulations predicted that, if SAR is not associated with SLA, this variation in SLA would cause a 47% decrease in LNCa along the SLA gradient, leading to a marginal net positive effect on RGR. In reality, SAR was positively related to SLA, showing a 3.9-fold variation, which largely compensated for the negative effect of SLA on LNCa. Consequently, LNCa values were almost constant across species and a positive SLA-RGR relationship was achieved.These results highlight the importance of leaf-root interactions in understanding interspecific differences in RGR.