Intra- and Inter-Plant Level Correlations among Floral Traits in Iris Gracilipes (Iridaceae)

Abstract

Although the sizes of individual flowers within one plant vary, few studies to date have investigated correlations among floral traits at the intra-plant level. Variations of the pleiotropic genes or linkage disequilibrium of genes, those have been said to create larger correlations between some combinations of traits than others at the inter-plant level, cannot predict intra-plant level correlations. In this study, correlations between several combinations of floral traits, including the number and volume of pollen grains and ovules, were investigated at both intra- and inter-plant levels in Iris gracilipes. The pattern of intra-plant level correlations was similar to that of inter-plant level correlations with some exceptions; correlations between functionally related traits tended to be larger than others at both levels. For example, correlations between sepal and petal size, and between petaloid style and filament length were large at both levels. This may be explained by the genetic and the developmental relationships between some combinations of traits, rather than by (co)variations of the peculiar properties of the individual plants such as genetic variations.