Searching for quantified observations

In this chapter the predictions made using the model are compared with the data available on spiral systems. A good agreement is found whenever a comparison is possible. In the last decade, theoretical consideration of phyllotaxis has attained a high degree of elegance which contrasts with a lack of quantitative evidence. However, conclusions may be drawn from a comparison between factual and theoretical phyllotaxis, as we will see. These may stimulate future observations, as well as a dialogue between the observer and the modeler.

Theories and models in phyllotaxis are meant to be compared with reality. There are many possible ways to test models. If for example a model is based on the hypothesis that a substance is responsible for the generation of phyllotactic patterns, then this hypothesis can be directly tested by trying to identify the substance and its pathways in the plant. A model for the photorealistic reproduction of plants and patterns is tested directly by a visual comparison between the computer–generated images and the plants themselves. If a model is based on the assumption that the energy costs paid by plants are responsible for the various patterns that can arise, then the model would be tested directly by measuring the wavelengths absorbed by chloroplasts and carotenoids of each species.