Functional control of nitrogen distribution in heterogeneous plant canopies

光能是光合作用的驱动力，而氮素往往是光合作用装置构建的限制因素。为了有效地利用光合作用中的光能，植物不断地调整它们的叶片性状以适应不同的冠层内光照条件。这些适应机制体现在氮素在光合作用功能、叶片氮素浓度和叶面积/叶质量比之间分配的改变上。通过模拟方法预测，当冠层中氮素和光强的梯度协调时，整个植物的光合作用达到最大。然而，这些模型没有考虑到冠层结构和光照分布的空间(水平)异质性，这在许多高价值作物中是现实的。该项目旨在通过功能-结构植物模型(FSPM)对(异质)冠层结构的显式表达，更好地了解冠层中氮素的分布和光合氮的分配。所获得的知识应该为量化光环境、氮素有效性和基因变异对氮素分配和氮素分配的影响提供基础。这一改进的数量认识旨在应用于以科学为基础的改良作物管理措施，如氮肥、补光、种植安排或整枝制度，并帮助根据预期的生长光照条件选择品种。

Light energy is the driving force of photosynthesis, and nitrogen is often a limiting factor for the construction of the photosynthetic apparatus. Plants continuously adjust their leaf traits to the variable intra-canopy light conditions in order to utilize the light energy efficiently for photosynthesis. These adaption mechanisms can be observed in the modifications of nitrogen partitioning between photosynthetic functions, leaf nitrogen concentration, and the ratio between leaf area and leaf mass. It has been predicted by modelling approaches that when the gradients of nitrogen and light intensity are coordinated in the canopy, whole plant photosynthesis reaches its maximum. However, these models do not take into account spatial (horizontal) heterogeneity in canopy structure and light distribution, which is the reality in many high value crops. This project aims to better understand canopy nitrogen distribution and photosynthetic nitrogen partitioning in heterogeneous plant canopies, using an explicit representation of (heterogeneous) canopy structure by a functional-structual plant model (FSPM). The knowledge gained should provide the basis for quantification of the influence of light environment, nitrogen availability and genotypic variation on nitrogen partitioning and nitrogen distribution. The improved quantitative understanding is intended to be applied for a science-based improvement crop management measures like nitrogen fertilization, supplemental lighting, planting arrangement or training system, and to assist in the choice of the cultivars according to the expected growth light conditions.