Hu Yi, Barrett Spencer C H, Zhang Da-Yong, Liao Wan-Jin
State Key Laboratory of Earth Surface Processes and Resource Ecology and MOE Key Laboratory for Biodiversity Science and Ecological Engineering College of Life Sciences Beijing Normal University Beijing 100875 China.
Department of Ecology and Evolutionary Biology University of Toronto 25 Willcocks Street Toronto Ontario M5S 3B2 Canada.
Ecol Evol. 2015 Nov 2;5(22):5423-5431. doi: 10.1002/ece3.1801. eCollection 2015 Nov.
Hermaphrodite plants commonly practice self-fertilization (selfing), but the mechanisms responsible vary depending on the mode of self-pollination, pollinator behavior, and degree of clonality. Whether selfing occurs within (autogamy) or between flowers (geitonogamy) is of evolutionary significance because their fitness consequences differ. We used floral manipulations and genetic markers to determine the relative contribution of autogamy and within- versus between-ramet geitonogamy to the selfing rate of the bumblebee-pollinated, clonal herb . Data on flowering phenology and bumblebee foraging were also collected to determine opportunities for different modes of self-pollination. Autogamy accounted for only 12% of the selfing rate with the remainder resulting from geitonogamy. Whole-ramet emasculation of clones with multiple ramets reduced selfing by 78%, indicating that within-ramet geitonogamy contributed significantly (68%) to total selfing. Selfing of single-ramet plants was 44% less than multiple-ramet plants, indicating that the contribution of between-ramet geitonogamy was substantially less (20%) than within-ramet geitonogamy, probably because of bumblebee foraging behavior. Our results demonstrate for the first time in a clonal plant that within-ramet geitonogamy is substantially greater than between-ramet geitonogamy and highlight the importance of considering the influence of clonal architecture and pollinator foraging on modes of self-pollination.
雌雄同体植物通常进行自花受精（自交），但其机制因自花授粉方式、传粉者行为和克隆程度而异。自交发生在花朵内部（闭花受精）还是花朵之间（同株异花授粉）具有进化意义，因为它们的适合度后果不同。我们通过花部操作和遗传标记来确定闭花受精以及分株内与分株间同株异花授粉对这种由大黄蜂传粉的克隆草本植物自交率的相对贡献。我们还收集了开花物候和大黄蜂觅食的数据，以确定不同自花授粉方式的机会。闭花受精仅占自交率的12%，其余部分来自同株异花授粉。对具有多个分株的克隆体进行全分株去雄使自交率降低了78%，这表明分株内同株异花授粉对总自交的贡献显著（68%）。单分株植物的自交率比多分株植物低44%，这表明分株间同株异花授粉的贡献（20%）远低于分株内同株异花授粉，可能是由于大黄蜂的觅食行为。我们的结果首次在一种克隆植物中证明，分株内同株异花授粉远大于分株间同株异花授粉，并强调了考虑克隆结构和传粉者觅食对自花授粉方式影响的重要性。
