Laboratorio de Botánica, Facultad de Farmacia, Departamento de Biología Vegetal, Universidad de Santiago de Compostela, Campus Sur s/n, Santiago, E-15706 Spain.
Am J Bot. 2000 Apr;87(4):493-501.
We investigated patterns of fruit and seed production on inflorescences of a population of Pancratium maritimum in northwest Spain over a 2-yr period. Initial findings showed that the earliest opening flowers on an inflorescence are more likely to set fruit and produce more seeds than later opening flowers and that this pattern is maintained throughout the flowering season. Supplementary pollination and flower-removal experiments were performed to investigate whether the observed pattern is attributable (a) to variation in pollen receipt, (b) to sequestration of resources by the earliest flowers on an inflorescence, and/or (c) to "architectural" limitations on the fruit/seed production of later flowers. Supplementary pollination did not improve fruit or seed production by late flowers in either of the 2 yr of study. In flower-removal experiments, the remaining flowers showed improved fruit set and mean number of seeds per flower, by comparison with flowers in the same position on control inflorescences. When all flowers except the latest third were removed, these showed fruit set and seed production similar to those of early flowers on control inflorescences. These results strongly suggest that the observed within-inflorescence patterns of fruit and seed production in P. maritimum are mainly attributable to competition for resources (i.e., explanation b), though other adaptive explanations cannot be ruled out.
我们调查了西班牙西北部一个 Pancratium maritimum 种群的花序上的果实和种子生产模式，为期 2 年。初步研究结果表明，花序上最早开放的花朵比后期开放的花朵更容易结果和产生更多的种子，而且这种模式在整个花期内都保持不变。我们进行了补充授粉和花朵去除实验，以研究观察到的模式是否归因于(a)花粉接收的变化，(b)花序上最早的花朵对资源的掠夺，和/或(c)对后期花朵的果实/种子生产的“结构”限制。在 2 年的研究中，补充授粉都没有改善晚期花朵的果实或种子产量。在花朵去除实验中，与对照花序中同一位置的花朵相比，剩余的花朵表现出更好的结实率和每朵花的平均种子数。当除去除最晚的三分之一之外的所有花朵时，这些花朵的结实率和种子产量与对照花序上的早期花朵相似。这些结果强烈表明，P. maritimum 中观察到的花序内果实和种子生产模式主要归因于资源竞争（即解释 b），尽管不能排除其他适应性解释。
