AgroParisTech, UMR Environnement et Grandes Cultures, Thiverval-Grignon, France.
Ann Bot. 2011 Apr;107(5):765-79. doi: 10.1093/aob/mcq205. Epub 2010 Oct 27.
This study aimed to characterize the interaction between architecture and source-sink relationships in winter oilseed rape (WOSR): do the costs of ramification compromise the source-sink ratio during seed filling? The GreenLab model is a good candidate to address this question because it has been already used to describe interactions between source-sink relationships and architecture for other species. However, its adaptation to WOSR is a challenge because of the complexity of its developmental scheme, especially during the reproductive phase.
Equations were added in GreenLab to compute expansion delays for ramification, flowering of each axis and photosynthesis of pods including the energetic cost of oil synthesis. Experimental field data were used to estimate morphological parameters while source-sink parameters of the model were estimated by adjustment of model outputs to the data. Ecophysiological outputs were used to assess the sources/sink relationships during the whole growth cycle.
First results indicated that, at the plant scale, the model correctly simulates the dynamics of organ growth. However, at the organ scale, errors were observed that could be explained either by secondary growth that was not incorporated or by uncertainties in morphological parameters (durations of expansion and life). Ecophysiological outputs highlighted the dramatic negative impact of ramification on the source-sink ratio, as well as the decrease in this ratio during seed filling despite pod envelope photosynthesis that allowed significant biomass production to be maintained.
This work is a promising first step in the construction of a structure-function model for a plant as complex as WOSR. Once tested for other environments and/or genotypes, the model can be used for studies on WOSR architectural plasticity.
本研究旨在描述冬油菜（WOSR）中结构与源库关系之间的相互作用：分枝的成本是否会在种子灌浆期间影响源库比？GreenLab 模型是解决这个问题的一个很好的候选者，因为它已经被用于描述其他物种的源库关系和结构之间的相互作用。然而，由于其发育方案的复杂性，特别是在生殖阶段，将其应用于 WOSR 是一个挑战。
在 GreenLab 中添加了方程来计算分枝的扩展延迟、每个轴的开花和荚果的光合作用，包括油脂合成的能量成本。实验田间数据用于估计形态参数，而模型的源库参数则通过调整模型输出与数据来估计。生理生态输出用于评估整个生长周期的源库关系。
初步结果表明，在植物尺度上，该模型正确地模拟了器官生长的动态。然而，在器官尺度上，观察到了误差，这些误差要么可以通过未纳入的次生生长来解释，要么可以通过形态参数（扩展和生命的持续时间）的不确定性来解释。生理生态输出强调了分枝对源库比的巨大负面影响，以及尽管荚果包膜光合作用允许维持大量生物量的产生，但在种子灌浆期间源库比的下降。
这项工作是为像 WOSR 这样复杂的植物构建结构-功能模型的一个有前途的第一步。一旦在其他环境和/或基因型下进行测试，该模型就可以用于研究 WOSR 的结构可塑性。
