Defining the scope for altering rice leaf anatomy to improve photosynthesis: a modelling approach

Leaf structure plays an important role in photosynthesis. However, the causal relationship and the quantitative importance of any single structural parameter to the overall photosynthetic performance of a leaf remains open to debate. In this paper, we report on a mechanistic model, eLeaf, which successfully captures rice leaf photosynthetic performance under varying environmental conditions of light and CO2. We developed a 3D reaction-diffusion model for leaf photosynthesis parameterised using a range of imaging data and biochemical measurements from plants grown under ambient and elevated CO2 and then interrogated the model to quantify the importance of these elements. The model successfully captured leaf-level photosynthetic performance in rice. Photosynthetic metabolism underpinned the majority of the increased carbon assimilation rate observed under elevated CO2 levels, with a range of structural elements making positive and negative contributions. Mesophyll porosity could be varied without any major outcome on photosynthetic performance, providing a theoretical underpinning for experimental data. eLeaf allows quantitative analysis of the influence of morphological and biochemical properties on leaf photosynthesis. The analysis highlights a degree of leaf structural plasticity with respect to photosynthesis of significance in the context of attempts to improve crop photosynthesis.

Automated summary

Leaf structure plays a crucial role in photosynthesis, but the relationship between a single structural parameter and the overall photosynthetic performance is still debated. In this study, a mechanistic model called eLeaf was developed to capture the photosynthetic performance of rice leaves under various environmental conditions. The model successfully quantified the importance of different elements by analyzing imaging data and biochemical measurements. The results showed that photosynthetic metabolism was the major driver of increased carbon assimilation under elevated CO2 levels, and various structural elements made positive and negative contributions. The findings provide theoretical support for experimental data and highlight the significance of leaf structural plasticity in improving crop photosynthesis.