Manipulation of Anthocyanin Production in Saponaria officinalis Using Sun Screen

Indianapolis, IN

Saponaria officinalis is a protandrous perennial herb, meaning individual flowers transition from male to female reproductive stages. Floral gender change is correlated with an increase in anthocyanin pigment concentration in the petals, so that flowers turn pink as the transformation takes place. Previous research has shown the increase in anthocyanins is proportional to the amount of sunlight to which flowers are exposed: lower amounts of anthocyanins are found in flowers from plants grown in shade vs. sun. To determine the effects of floral color change on fitness, it is necessary to be able to manipulate floral color while holding other variables, such as flower size and shape, constant. The experiment presented here tested the effectiveness of applying cosmetic sunscreen chemicals to petals, in order to manipulate the production of anthocyanins in flowers on the same plant. Flowers were treated in their early male phase by brushing petals with an inert oil+sunscreen, oil only, or with nothing as a control. Data was collected when the flowers reached female phase. The reflectance and absorption spectrum were compared for all three treatments. Flowers treated with sunscreen were significantly less pink compared to the control or oil treated flowers. New inert oil needs to be tested because the flowers treated with oil only had some effect on the pinkness and had less biomass compared to the control flowers. Overall, this method holds promise to study the fitness effects of floral color change in this species if petal color affects pollinator behavior.