Evidence of delayed selfing in Cistaceae

Several aspects of the reproductive biology of Fumana juniperina were analyzed to find out whether delayed selfing occurs within a representative natural population in southwest Sardinia. Similar fruit set was obtained after autonomous, within-flower, and between-flower self-pollination (0.35, 0.53, and 0.46, respectively), cross-pollination (0.45), and control (0.39). Seed set and seed mass did not differ significantly between pollination treatments (P > 0: 05). Autonomous self-pollination was favored at the end of floral anthesis, when the petals fell and the sepals closed and pushed the anthers onto the stigma, making contact. No pollinators were seen visiting the flowers during the 42-h observation period, and the stigmatic pollen load on open-pollinated flowers, collected after the petals had fallen and before anther and stigma contact had occurred, was not enough to fertilize all the ovules. Low levels of inbreeding depression were found for fruit set (delta = -0.167), seed set (delta = -0.086), seed mass (delta = -0.008), and seed germination (delta = -0.052). These results support the idea that F. juniperina is self-compatible and capable of autonomous self-pollination through changes in the position of the stigma and anthers at the end of floral anthesis. This is a case of how delayed selfing can be an efficient mating strategy that ensures reproduction in this plant when pollinators are scarce. This is the first time that a mechanism of delayed selfing has been described within the family Cistaceae.