Functional Control of Photosynthetic Nitrogen in Heterogeneous Plant Canopies

Research output: Thesis › Doctoral thesis

Authors

  • Yi-Chen Pao

Research Organisations

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Details

Original languageEnglish
QualificationDoctor rerum horticulturarum
Awarding Institution
Supervised by
  • Hartmut Stützel, Supervisor
Date of Award23 Sept 2021
Place of PublicationHannover
Publication statusPublished - 2021

Abstract

Acclimation of leaf photosynthetic traits to fluctuating environments is a key mechanism to maximize fitness. Constant tracking of light environments is crucial for species with continuously leaf-forming nature, such as greenhouse cucumber (Cucumis sativus L.). To capture the acclimation dynamics, we propose that light interception and leaf ontogeny shape the acclimation processes through nitrogen investment in light capture and utilization functions, which determines the rate-limiting step in the photosynthetic machinery. Based on this concept, a dynamic model of protein turnover (synthesis and degradation) was implemented to simulate nitrogen investment in three photosynthetically functional pools depending on light, nitrogen supply and leaf age, in conjunction with a 1D light model using multilayer model (MLM) and a 3D light model using a functional-structural model (FSM). The light dependency of protein synthesis was able to explain the photosynthetic acclimatory response to fluctuating light, and to predict canopy photosynthesis with comparable accurracy using either the MLM or the FSM. Using the MLM, the degree of optimality of photosynthetic nitrogen use for maximizing daily canopy photosynthesis was quantified by manipulating the protein synthesis rates. Photosynthetic nitrogen distribution between leaves was found optimal in the greenhouse cultivar Aramon, except that canopy photosynthesis could be improved by enhanced acropetal reallocation under nitrogen-limiting conditions. Photosynthetic nitrogen partitioning within induvidual leaves was optimal for the cultivar Aramon but not for the field cultivar SC-50 when grown in a single-stem structure, probably due to the coordination of function with structure developed during breeding. In contrast to Aramon, SC-50 has less total photosynthetic nitrogen but a partitioning strategy more sensitive to light. The proposed modelling framework provides an interpretation for acclimatory mechanisms under fluctuating light, and enables in silico manipulations and tests of photosynthetic acclimation in heterogeneous canopies. Possible extensions to the framework are also discussed.

Cite this

Functional Control of Photosynthetic Nitrogen in Heterogeneous Plant Canopies. / Pao, Yi-Chen.
Hannover, 2021. 177 p.

Research output: Thesis › Doctoral thesis

Pao, Y-C 2021, 'Functional Control of Photosynthetic Nitrogen in Heterogeneous Plant Canopies', Doctor rerum horticulturarum, Leibniz University Hannover, Hannover. https://doi.org/10.15488/11344
Pao YC. Functional Control of Photosynthetic Nitrogen in Heterogeneous Plant Canopies. Hannover, 2021. 177 p. doi: 10.15488/11344
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