Mehrskalige Funktions-Struktur-Modellierung von Pflanzen am Beispiel von Apfelbäumen
Biochemie und Biophysik der Pflanzen
Softwaretechnik und Programmiersprachen
Statistik und Ökonometrie
Zusammenfassung der Projektergebnisse
Functional-structural plant models (FSPMs) are simulation models representing the 3-dimensional structure, growth and (aspects of) physiological functioning of single plants or plant stands. They are a versatile tool to study the adaptive significance of morphological traits, to test hypotheses about the connection between structure and function, and to represent knowledge about different aspects of plant behaviour in a coherent way. We started a collaborative research project with three partners from France (Agrocampus Ouest in Angers, UMR AGAP in Montpellier and Centrale Supélec in Paris) to model apple trees. Since FSPMs are usually technically implemented within dedicated software environments on computers and different teams use different software platforms for this purpose, a major technical task was first to create a generalizable interface between FSPM-platforms. In our case, the widelyused platforms OpenAlea (from UMR AGAP) and GroIMP (from our team in Göttingen) were involved and were the first to link by an information-exchange mechanism which was designed to enable cross-platform joint model runs, including a data flow in both directions in a way that each model, hosted on its platform, can provide the simulation results of the processes for which it is specialized and send it to the other model, thus resulting in a synergistic, iterated interplay of models, which then become submodels of a compound model ("retroaction scenario"). To build such a "bridge" between models (and underlying software platforms), several technical challenges had to be mastered: Translation of the syntax of model descriptions on the platforms, adaptation to the semantics of objects in the participating models, definition of sufficiently generic data structures and file formats for the information exchange (with the perspective to define a standard), and enhancement of the efficiency of calculations by exploiting parallelism. In a joint work with UMR AGAP, we created such a bridge and tested it successfully at (currently) simple test plants and larger apple trees, where the growth was simulated by a model running on OpenAlea and colour or light calculations for single leaves were executed on GroIMP. Light is already very important for determining where and how much a plant will grow. To enable the inclusion of other factors, namely water supply and local availability of carbohydrates, a second focus of our work was the numerical simulation of water flow in the xylem and assimilate flow in the phloem in an apple branch. In a first step, we were able to implement (in joint work with our partner from Agrocampus Ouest) a model on GroIMP, based on differential equations, representing both flows and their interconnection in a single branch of an apple tree, including its organs (leaves, fruits, internodes) and at high temporal resolution. The model is coupled with GroIMP's light model and is driven by transpiration; it shows already a reasonable qualitative behaviour, but its parameterization has still to be improved and the input to be made dynamically dependent on the course of lighting, temperature and stomatal conductance. It will then become part of an integrated apple tree model by the interface mentioned above. A third field of work is the analysis of simulation models. FSPMs tend to become complex and computationally demanding. A way to simplify them is to find out which of the model parameters are essential and which of them have only small influence on the output. For this "sensitivity analysis", refined rigorous mathematical methods were adapted and further developed by our partner at Centrale Supélec. They created also a software platform providing access to these techniques, but again, to be able to apply them to our models, a software interface to our platform had to be implemented first. After doing this, we were able to analyze an FSPM simulating light interception of a tree (albeit not our apple tree model, since this was not yet developed far enough). All three lines of research – linking models from different platforms, simulating transport processes in fruit trees, and analyzing and simplifying complex FSPMs – will flow together in the future. The goal is to obtain a better understanding of apple tree growth and physiology in relation to lighting conditions (i.e., competition by other trees), water supply (or drought stress) and management practices which change the 3-d structure of the trees. This can then potentially help to improve fruit yield and quality.
Projektbezogene Publikationen (Auswahl)
- (2016): Impact of geometrical traits on light interception in conifers: analysis using an FSPM for Scots pine. In: Proceedings 2016 IEEE International Conference on Functional-Structural Plant Growth Modeling, Simulation, Visualization and Applications (FSPMA 2016), 7-11 Nov. 2016, Qingdao (China), IEEE Press, Beijing 2016, pp. 194-203
Katarína Streit, Michael Henke, Benoit Bayol, Paul-Henry Cournède, Risto Sievänen, Winfried Kurth
(Siehe online unter https://doi.org/10.1109/FSPMA.2016.7818307) - (2016): Multiscale functional-structural plant modelling at the example of apple trees. Project description. In: Proceedings 2016 IEEE International Conference on Functional-Structural Plant Growth Modeling, Simulation, Visualization and Applications (FSPMA 2016), 7-11 Nov. 2016, Qingdao (China), IEEE Press, Beijing 2016, pp. 1-5
Benoît Bayol, Paul-Henry Cournède, Julien Sainte-Marie, Gautier Viaud, Faustino Chi, Winfried Kurth, Qinqin Long, Johannes Merklein, Katarína Streit, Evelyne Costes, Vincent Migault, Benoît Pallas, Gerhard Buck-Sorlin, Magalie Poirier-Pocovi, Christophe Pradal
(Siehe online unter https://doi.org/10.1109/FSPMA.2016.7818281) - (2017): A design pattern in XL for implementing multiscale models, demonstrated with a fruit tree simulator. In: Proceedings X Int. Symp. on Modelling in Fruit Research and Orchard Management, Acta Horticulturae, 1160 (2017), pp. 35-41
Winfried Kurth, Yongzhi Ong
(Siehe online unter https://doi.org/10.17660/ActaHortic.2017.1160.6) - (2017): A logical data exchange model for adapting different methods abstracting plant architecture. In: 2017 2nd International Conference on Knowledge Engineering and Applications ICKEA 2017, Oct. 21-23, 2017, Imperial College London, UK (IEEE 2017), ISBN 978-1-5386-2149-3, pp. 39-43
Qinqin Long, Winfried Kurth
(Siehe online unter https://doi.org/10.1109/ICKEA.2017.8169899) - (2018): A dynamic model of xylem and phloem flux in an apple branch. In: 6th Internat. Symposium on Plant Growth Modeling, Simulation, Visualization and Applications PMA 2018, 4-8 Nov. 2018, Hefei, China, Proceedings, Pages: S. 50 - 55
Johannes Merklein, Magalie Poirier-Pocovi, Gerhard Buck-Sorlin, Winfried Kurth, Qinqin Long
(Siehe online unter https://doi.org/10.1109/PMA.2018.8611561) - (2018): An architecture for the integration of different functional and structural plant models. In: Proceedings of the 7th Internat. Conf. on Informatics, Environment, Energy and Applications IEEA 2018, 28-31 March 2018, Beijing, China, ACM Press, Beijing 2018, ISBN 978-1-4503-6362-4, pp. 107-113
Qinqin Long, Winfried Kurth, Christophe Pradal, Vincent Migault, Benoît Pallas
(Siehe online unter https://doi.org/10.1145/3208854.3208875)
