Analysis of Cellular Changes Associated with Morphological Changes in Color and Size of Petals of Saponaria officinalis

Saponaria officinalis is an angiosperm that produces flowers that undergo morphological changes in petal size, shape, and color, while transitioning from a male to female reproductive phase. The focus of this research study was to investigate the cellular mechanisms by which these changes occur. Petals were collected from flowers in male and female phases on plants growing in a disturbed site in Indianapolis. Epidermal peels were obtained from each petal and mounted on microscope slides. The cells in view were measured to determine the cell size and number as well as pigment distribution among the samples. The variables selected to test these differences include medium, gender, side of petal (top or bottom), and area (proximal or distal) on the petal. Preliminary data has shown male flowers to exhibit smaller cell size compared to female flowers as well as adaxial cells exhibiting larger cell size compared to abaxial cells. An increase in pigment accumulation was evident within the cells of petals from female phase flowers compared to male phase, resulting in the pink color seen in female phase flowers. Plasmolyzing the cells by mounting the tissue in saline helped demonstrate the pigments are mostly concentrated in water vacuoles of epidermal cells. Investigating the cellular mechanisms behind these morphological changes gives insight on how these changes impact the plant metabolically. If these changes are metabolically costly, it can be inferred these morphological changes offer an appropriate rise in plant fitness to outweigh these costs in order for natural selection to maintain them