Flower color polymorphism in Iris pumila - Why we definitely need in situ reflectance spectroscopy in population analysis and evolutionary studies of this model system

Abstract

Dwarf bearded iris - Iris pumila L. is a perennial clonal plant that exhibits huge flower colour polymorphism with white, yellow and various shades of purple and violet flowers. Maintenance of such polymorphism is very interesting evolutionary question in its own right. Moreover, flower colour is also used in determining individual clones, their size and population diversity - all very important aspects of further population and evolutionary studies on this model system. However, visual identification or use of digitalized images, while being a necessary first step, is not sufficient for this task. They are often subjective, dependent on light conditions, and covering only part of the spectrum - one that is visible to humans. In published papers that utilized flower colour in I. pumila, number of analyzed different colour variants ranged from nine to only three colour classes. Chemical analysis of different colour variants is a very useful tool and has also been applied, but it is hardly applicable for most population level analyses. We therefore consider portable reflectance spectrometer as the best available tool for those multiple tasks, and present preliminary results of its application in situ with wavelengths chosen to match the visible spectrum of I. pumila main pollinators.