Stamen movements and pollination in Ruta

Stamen movements and pollination in Ruta

Stamen movements and pollination in Ruta

In Ruta graveolens each stamen elevates to above the flower’s centre for anther dehiscence and then falls back before the next stamen elevates, producing a one-by-one rising and falling pattern of movement. Ren and Tang manipulate individual stamens and find that these movements can enhance pollen removal by presenting pollen in doses to pollinators. If a stamen is prevented from falling back, removal of pollen from the next anther to rise is reduced as pollinators are deterred by the presence of the empty anther and make shorter visits. Some flowers show simultaneous rising of all stamens at the end of anthesis and anthers touch the stigma, which may provide reproductive assurance by delayed self-pollination.