Ontogeny of flower parts on naturally growing Iris pumila clones: implications for population differentiation and...

Previous studies revealed significant phenotypic plasticity, genetic variability and population differentiation of flower morphometric traits on dwarf bearded iris Iris pumila. Also, study of I. pumila flowering phenology revealed significant impact of habitat type as well as population differentiation for flowering time. Since the flowering time can influence other flower traits, we performed this analysis of flower morphometric traits in three time points during the flower bud ontogenic development in two habitat types (open vs. shaded). Analysis revealed that for most of the traits greater trait values were recorded for open habitat but only on latter time points. For most of the analyzed traits direction of differences in bud stage was the opposite to the direction of differences in mature flower stage detected in previous studies. However, length of the stem, a trait that showed the greatest variability between habitats and populations and therefore greatest genetic differentiation and phenotypic plasticity, was significantly greater in the samples from the late flowering shaded habitat in all time samples, indicating that in case of this trait different mechanisms were involved. Those findings have implications for design of the future studies on I. pumila.