Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China.
Ann Bot. 2012 Oct;110(5):1017-25. doi: 10.1093/aob/mcs181. Epub 2012 Aug 7.
Stamen movements directly determine pollen fates and mating patterns by altering positions of female and male organs. However, the implications of such movements in terms of pollination are not well understood. Recently, complex patterns of stamen movements have been identified in Loasaceae, Parnassiaceae, Rutaceae and Tropaeolaceae. In this study the stamen movements in Ruta graveolens (Rutaceae) and their impact on pollination are determined.
Pollination effects of stamen movements were studied in Ruta graveolens, in which one-by-one uplifting and falling back is followed by simultaneous movement of all stamens in some flowers. Using 30 flowers, one stamen was manipulated either to be immobilized or to be allowed to move freely towards the centre of the flower but be prevented from falling back. Pollen loads on stigmas and ovule fertilization in flowers with or without simultaneous stamen movement were determined.
Pollen removal decreased dramatically (P < 0·001) when the stamen was stopped from uplifting because its anther was seldom contacted by pollinators. When a stamen stayed at the flower's centre, pollen removal of the next freely moved anther decreased significantly (P < 0·005) because of fewer touches by pollinators and quick leaving of pollinators that were discouraged by the empty anther. Simultaneous stamen movement occurred only in flowers with low pollen load on the stigma and the remaining pollen in anthers dropped onto stigma surfaces after stamens moved to the flower's centre.
In R. graveolens pollen removal is promoted through one-by-one movement of the stamen, which presents pollen in doses to pollinators by successive uplifting of the stamen and avoids interference of two consecutively dehisced anthers by falling back of the former stamen before the next one moves into the flower's centre. Simultaneous stamen movement at the end of anthesis probably reflects an adaptation for late-acting self-pollination.
雄蕊的运动通过改变雌、雄蕊的位置直接决定花粉的命运和交配模式。然而，这种运动对传粉的影响还没有得到很好的理解。最近，在茄科、卫矛科、芸香科和旱金莲科中发现了雄蕊运动的复杂模式。本研究旨在确定筋骨草（筋骨草科）雄蕊的运动及其对传粉的影响。
研究了筋骨草中雄蕊运动的传粉效应，其中一朵花中的一朵雄蕊依次向上抬起和落下，然后所有雄蕊同时向花的中心移动。使用 30 朵花，将一朵雄蕊固定或允许其自由向花的中心移动，但防止其落下。测定了有或没有雄蕊同时运动的花中柱头的花粉负荷和胚珠受精情况。
当阻止雄蕊向上抬起时，花粉去除率显著下降（P<0.001），因为其花药很少被传粉者接触。当雄蕊停留在花的中心时，下一个自由移动的花药的花粉去除率显著下降（P<0.005），因为传粉者接触较少，而且由于空花药的阻碍，传粉者很快离开。雄蕊的同时运动仅发生在柱头花粉负荷较低的花朵中，并且在雄蕊移动到花的中心后，剩余的花粉落在柱头表面。
在筋骨草中，雄蕊的逐个运动促进了花粉的去除，通过雄蕊的逐个向上抬起，将花粉以剂量的形式呈现给传粉者，并通过前一个雄蕊在随后的雄蕊进入花的中心之前落下，避免了两个相继开裂的花药之间的干扰。在花期结束时的雄蕊同时运动可能反映了对迟发性自交的适应。
