CANON: A Canonical Composition for Building Plant Shoots From the Bottom Up
Crop Modeling and Decision Support
The phytomer concept has been useful for understanding plant development and architecture. Commonly the phytomer has been viewed as a vegetative unit consisting of a leaf, node, internode, and axillary bud, with this unit repeated within and among shoots. This definition can be extended to the inflorescence structure. Based on available knowledge and objectives, models may not fully incorporate phytomer concepts, rather some phytomers may be aggregated into a single component such as a grain
... such as a grain component. The continuing development of object-oriented (00) design and associated programming languages is providing opportunities for better incorporating phytomer concepts into models. For instance, the use of a Composite Pattern in an object-oriented (00) design facilitates implementation of different scales from the phytomer to a mixture of single and aggregated phytomers for different plant components. The objectives of this paper are to use winter wheat (Triticum aestivum L.) to illustrate 0 1 how plants build their canopies by the appearance, growth, and abortion/senescence of phytomer units, and © present a conceptual prototype for translating this botanical abstraction into an 00 design of a plant model, CANON, so called because the interplay of repeating phytomers is analogous to the repeating melodies of a musical composition called a canon. In CANON 00 design, the canopy is built by the addition of phytomer units that have a consistent type of communication with adjoining phytomers. This communication matches the 00 structural composite design pattern described, where objects are represented in part-whole hierarchies by tree structures, with uniform treatment of individual objects and compositions of objects. At any point, the following sub-hierarchy is viewed as a single entity thus allowing parts of the hierarchy to be replaced with a single object, without affecting the preceding part of the hierarchy. This approach allows specification of sub-models of different levels of detail which could be selected at implementation or run-time. Initial implementation of the proof-of-concept using winter wheat (Triticum aestivum L.) vegetative phytomers is presented.