Maturation timing of stamens and pistils in the dioecious plant Silene latifolia

Abstract

The dioecious plant Silene latifolia depends on nocturnal insects for pollination. To increase the chance of cross-pollination, pollen grains seem to be released and stigmas seem to be receptive simultaneously at night. We divided the floral development of S. latifolia into 1-20 stages, and determined the timetables of male and female function. The corolla of both male and female flowers opens at sunset (1900hours) and closes at sunrise (0900hours). To investigate the period of the reproductive phase of male and female function, we measured the germination rate on a pollen medium and the pollen germination rate on stigma during the period when stamens and stigmas were viable in the timetable. Male flowers had early- and late-maturing stamens that had the highest pollen viability, germination rate and pollen tube growth at midnight (0000hours) at 1day after flowering (DAF) and 0000hours at 2 DAF. In contrast, female flowers maintained a germination rate of nearly 100% from 1800hours at 1 DAF to 1200hours at 3 DAF. These results suggested that S. latifolia transferred the matured pollen grains from male flowers to female flowers only at night.