Buide M L, Guitian J
Department of Botany, Pharmacy, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain.
Ann Bot. 2002 Dec;90(6):691-9. doi: 10.1093/aob/mcf251.
The breeding system of the dichogamous hermaphrodite species Silene acutifolia, endemic to north-west Spain and north and central Portugal, is examined. Pollen germinability and style-stigma receptivity were analysed to determine whether protandry is a barrier to self-fertilization. By 48 h after anthesis, pollen germinability had declined to approx. 10 %. The short straight styles are not receptive when flowers first open. They gradually elongate and curve outwards, develop stigma papillae and become receptive. There is no clear separation between stigma and style: the stigma papillae appear in a line along the length of the style. Fruit set is high regardless of pollen source; however, seed set is significantly reduced after both spontaneous and facilitated autogamy. Seed set following spontaneous autogamy was 30 % (86 % in controls) in 1998 and 33 % (87 % in controls) in 1999. Seed set following facilitated autogamy was 62 % (86 % in controls) in 1998 and 67 % (89 % in controls) in 1999. Thus, separation of the male and female phases does not prevent production of seeds by self-pollination, although it does reduce the likelihood of this. Furthermore, results of the present experiments indicate that this species has no self-incompatibility mechanisms (self-compatibility index = 0.98). The selfing rate in the study population was 0.41, which is supported by the lack of self-incompatibility systems and by the incomplete protandry.
对西班牙西北部以及葡萄牙北部和中部特有的二型雌雄同体物种尖叶蝇子草的繁育系统进行了研究。分析了花粉可萌发率和花柱 - 柱头可授性，以确定雄性先熟是否是自花受精的障碍。开花后48小时，花粉可萌发率已降至约10%。花朵刚开放时，短而直的花柱没有可授性。它们逐渐伸长并向外弯曲，发育出柱头乳突并变得具有可授性。柱头和花柱之间没有明显的区分：柱头乳突沿花柱长度呈线状出现。无论花粉来源如何，坐果率都很高；然而，在自然自花授粉和人工辅助自花授粉后，结实率都显著降低。1998年自然自花授粉后的结实率为30%（对照为86%），1999年为33%（对照为87%）。1998年人工辅助自花授粉后的结实率为62%（对照为86%），1999年为67%（对照为89%）。因此，雄性和雌性功能期的分离虽然确实降低了自花授粉产生种子的可能性，但并不妨碍通过自花授粉产生种子。此外，本实验结果表明该物种没有自交不亲和机制（自交亲和指数 = 0.98）。研究种群中的自交率为0.41，这得到了缺乏自交不亲和系统以及不完全雄性先熟的支持。
