Floral color change and asexual seed production in Fuchsia thymifolia (Onagraceae)

Abstract

Floral color change and the asexual seed production (apomixis) are two phenomena rarely studied in angiosperms. In this study we assess both phenomena in Fuchsia thymifolia, a gynodioecious species where female plants, that only produce female flowers, and hermaphroditic plants coexist. To explore the floral color change, flower buds were marked on female and hermaphrodite plants, which were censused and daily photographed. To determine seed production by apomixis, in two natural populations from Michoacán, female plants were used where flower buds were excluded from pollinators and fruit production was subsequently evaluated. We found that floral color change occurs in both female and hermaphroditic flowers and this change occurs regardless of pollination. When the flowers open, the flowers were white, and then changed to pink during the third and fourth day and finally to deep reddish the last days of the flowers (day 5 to 7-8). In addition, female flowers were more long-lived than hermaphrodite ones. Regarding apomixis, in both populations studied and for two years, between 16 and 20% of the bagged flowers produced ripe fruits. The floral color change is similar to that detected in other species and, in general, the dark coloration coincides with the absence of floral rewards in the hermaphrodite flowers or with the loss of stigma receptivity in the female flowers. Regarding apomixis, molecular studies are required to confirm that the seeds obtained are genetically identical to the female plants, as is expected in this phenomenon.