Cuevas Julián, Polito Vito S
Department of Crop Production, University of Almería, Almería, Spain.
Ann Bot. 2004 May;93(5):547-53. doi: 10.1093/aob/mch079. Epub 2004 Mar 22.
Andromonoecy, as a breeding system, has generated a considerable body of theory in terms of sexual selection, but extended records comparing the performance of pollen grains from staminate versus hermaphrodite flowers are still sparse. The objective in this study was to elucidate the role of staminate flowers in the andromonoecious breeding system of olive (Olea europaea).
To determine the meaning of staminate flowers, an evaluation was made of resource allocation to, and phenology of, staminate and hermaphrodite flowers in the cultivar 'Mission', and a comparison was made of the male function between both kinds of flowers.
Dry weight of hermaphrodite flowers was 19 % greater than dry weight of staminate flowers arising in comparable positions of the panicle. This difference was mainly due to pistil and petal weight; there were no significant differences in stamen weight. There were no significant differences between staminate and hermaphrodite flowers in either amount of pollen per anther, or pollen quality as determined by pollen viability, germinability or ability to fertilize other flowers. There was no significant link between gender and time of anthesis. However, position of the flower within the panicle correlated with time of anthesis and gender. Flowers at the apex and at primary pedicels tended to be hermaphrodite and open earlier, whereas flowers arising in secondary pedicels were mainly staminate and were commonly the last to reach anthesis.
It is proposed that the main advantage provided by production of staminate flowers in olive is to enhance male fitness by increasing pollen output at the whole plant level, although a relict function of attracting pollinators cannot be completely discarded.
作为一种繁育系统，雄花两性花同株现象在性选择方面已经产生了大量理论，但比较雄花与两性花花粉粒表现的长期记录仍然很少。本研究的目的是阐明雄花在油橄榄（Olea europaea）雄花两性花同株繁育系统中的作用。
为了确定雄花的意义，对‘使命’品种中雄花和两性花的资源分配及物候进行了评估，并比较了两种花的雄性功能。
两性花的干重比在圆锥花序相同位置产生的雄花干重大19%。这种差异主要归因于雌蕊和花瓣的重量；雄蕊重量没有显著差异。雄花和两性花在每花药花粉量或由花粉活力、发芽能力或给其他花授粉能力所确定的花粉质量方面均无显著差异。性别与开花时间之间没有显著关联。然而，花在圆锥花序中的位置与开花时间和性别相关。圆锥花序顶端和一级花梗上的花倾向于是两性花且开放较早，而二级花梗上产生的花主要是雄花，通常是最后达到开花期的。
有人提出，油橄榄产生雄花的主要优势在于通过在整株水平上增加花粉产量来提高雄性适合度，尽管吸引传粉者的残留功能也不能完全排除。
