The effects of gender and plant architecture on allocation to flowers in dioecious Silene latifolia (Caryophyllaceae)

In dioecious species, reproductive allocation in females and males may differ as a result of the different reproductive functions and needs of the two sexes. In Silene latifolia (Caryophyllaceae), males invested a total of 11% more biomass in flowers than females. However, individual female Bowers were 2.6 times heavier than individual male flowers (on a dry mass basis), had significantly heavier sepals and pedicels, but not petals, and exceeded male flowers for five linear measures. Individual female flowers also contained 2.7 times more N and 2.9 times more P than individual male flowers. In females, N (on a mg/mg basis) was concentrated in ovules, nectary, petals, and styles and P was concentrated in ovules, nectary, styles, and petals. In males, N and P were concentrated in anthers, anthophor, and petals. Within flowers, the three currencies did not always predict each other, as anthers in males and ovules and styles in females contained higher, while sepals in both sexes contained lower, proportions of both nutrients than of biomass. Flower number was highly influenced by gender, pollination, and architecture. Males produced 2.9 times more flowers than unpollinated females and 14.3 times more flowers than pollinated females. In females, pollination of flowers on one of the two main inflorescence branches significantly reduced the number of flowers produced on that branch, both in comparison to the other inflorescence branch on the same plant and in comparison to the corresponding branch on control plants. Flower number also differed between the two inflorescence branches on control plants, indicating the importance of plant architecture on dower production. It is clear that selection can lead to different reproductive allocation patterns in females and males and that these patterns may vary depending on currency and in response to pollination and architecture in females.