Cátedra de Botánica, Laboratorio de Biología Reproductiva, Facultad de Ciencias Naturales, Universidad Nacional de Salta, Salta, Argentina.
Plant Biol (Stuttg). 2012 Jan;14(1):171-8. doi: 10.1111/j.1438-8677.2011.00489.x. Epub 2011 Jul 25.
The pollen:ovule ratio (P/O) has traditionally been used as a rough estimator of plant breeding systems. It has been shown that plant breeding systems are associated with particular floral traits. In this study, we determined the P/O in 21 Leguminosae species from Argentina and explored relationships between P/O and taxonomic position, flower size, floral rewards, pollen presentation and pollination mechanisms. According to the results, 15 out of the 21 species classified were obligate xenogamous, although some of them have been recorded as facultative xenogamous in previous studies. There was a significant effect of taxonomic position (genus), reward type and pollination mechanism on P/O. Species offering only nectar as a floral reward (which were species with a brush mechanism) had a significantly lower P/O than species offering pollen or pollen and nectar. Species with the brush pollination mechanism had the lowest P/O, while species with valvular and pump mechanism had the highest P/O. However, pollen presentation (primary and secondary) and flower size did not have a significant effect on P/O. Our results demonstrate that P/O variability is determined by taxonomic position and pollination mechanism in this plant group.
胚珠比（P/O）一直被用作植物繁殖系统的粗略估算指标。已经表明，植物繁殖系统与特定的花部特征有关。在这项研究中，我们确定了来自阿根廷的 21 种豆科植物的 P/O，并探讨了 P/O 与分类位置、花的大小、花的报酬、花粉展示和传粉机制之间的关系。根据结果，21 种分类的物种中有 15 种是强制性异交的，尽管其中一些在之前的研究中被记录为兼性异交。分类位置（属）、报酬类型和传粉机制对 P/O 有显著影响。仅提供花蜜作为花的报酬的物种（具有毛刷机制的物种）的 P/O 明显低于提供花粉或花粉和花蜜的物种。具有毛刷传粉机制的物种具有最低的 P/O，而具有瓣膜和泵机制的物种具有最高的 P/O。然而，花粉展示（初级和次级）和花的大小对 P/O 没有显著影响。我们的结果表明，在这个植物群中，P/O 的变异性是由分类位置和传粉机制决定的。
