Modularity Versus Emergence: How to Cope with Complexity in Whole-Plant Physiology?

  • Lars H. WegnerEmail author


Complex, multigenic traits like growth, yield, or photosynthetic carbon assimilation are of central importance for our understanding of plant biology and are highly relevant for plant breeding, agriculture, and other applied plant sciences. Therefore, scientific description of complexity and the elucidation of its molecular basis have recently received increasing interest. Surprisingly though, less attention is given to the classical concepts of ‘modularity’ and ‘emergence’. Modular features of a biological system result from more or less autonomously acting (molecular) components, whereas novel, ‘emergent’ features emanate from their interaction. In the very limited work published on this issue, modularity and emergence were considered as strictly opposing concepts. Here, a new, semi-quantitative, heuristic approach is introduced describing the contribution of individual proteins to a complex trait (‘protein-trait relationships’). On a phenomenological basis, criteria are defined that allow to decide whether a protein is affecting the trait rather in a modular or emergent way, treating them as gradual, rather than mutually exclusive, features. The approach is exemplified by case studies related to photosynthetic carbon assimilation, making use of empirical data that are available from the literature.


CO2 Carbon assimilation Rubisco Control theory Growth Plant systems biology Photosynthesis: carbon reactions 



I would like to thank Prof. Dr. Rainer Matyssek, Weihenstephan, Germany; Prof. Dr. Sergey Shabala, Hobart, Australia; and Dr. Vadim Volkov, Davis, USA, for discussion and for critical reading of a draft version of the manuscript.


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© Springer Nature Switzerland AG 2019

Authors and Affiliations

  1. 1.Karlsruhe Institute of Technology, Institute for Pulsed Power and Microwave Technology (IHM)Eggenstein-LeopoldshafenGermany

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