Flowering phenology influences seed production and outcrossing rate in populations of an alpine snowbed shrub, Phyllodoce aleutica: effects of pollinators and self-incompatibility
Flowering phenology influences seed production and outcrossing rate in populations of an alpine snowbed shrub, Phyllodoce aleutica: effects of pollinators and self-incompatibility
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DOI：
10.1093/aob/mcp037
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发表时间：
2009-06-01
期刊：
影响因子：
4.2
通讯作者：
Kudo, Gaku
中科院分区：
文献类型：
--
作者：
Kameyama, Yoshiaki;Kudo, Gaku
由于融雪时间的差异，高山植物的生殖物候在当地种群之间存在很大差异，种群之间的结实率也存在很大差异。在不同融雪条件下，紫茎泽兰的开花物候、传粉媒介的利用率、结实率、开花季节的变化、传粉媒介的利用率、结实率、开花季节的变化、传粉媒介的利用率、传粉媒介的利用率和异交率进行了比较（自交亲和性或异种亲和性与一个共同发生的同属种）。开花发生顺序之间的人口反映融雪时间从7月中旬至8月下旬。7月下旬工蜂出现时，大黄蜂的造访频率大幅增加。结实率和异交率均随花期的推进而增加。虽然花是自交亲和和异源亲和，混合授粉实验表明，受精与同种，异交花粉优先于自交和杂交，表明一个隐藏的自交不亲和。在早期的融雪人群，种子生产是有限的花粉和自花受精是常见的。然而，遗传分析表明，自交后代并没有有助于维持人口，由于后期作用的近交depression.Great变化，在结实率和异交率的人口是由传粉者在本赛季的时间和神秘的自交不亲和性。尽管密集的花粉限制在早期的季节，自花受精的繁殖保证是不明显的。在传粉者利用率和开花结构的波动条件下，桐花树通过同种异交维持遗传组成。
Because of differences in snowmelt time, the reproductive phenologies of alpine plants are highly variable among local populations, and there is large variation in seed set across populations. Temporal variation in pollinator availability during the season may be a major factor affecting not only seed production but also outcrossing rate of alpine plants.Among local populations of Phyllodoce aleutica that experience different snowmelt regimes, flowering phenology, pollinator availability, seed-set rate, and outcrossing rate were compared with reference to the mating system (self-compatibility or heterospecific compatibility with a co-occurring congeneric species).Flowering occurred sequentially among populations reflecting snowmelt time from mid-July to late August. The visit frequency of bumble-bees increased substantially in late July when workers appeared. Both seed set and outcrossing rate increased as flowering season progressed. Although flowers were self-compatible and heterospecific compatible, the mixed-pollination experiment revealed that fertilization with conspecific, outcrossing pollen took priority over selfing and hybridization, indicating a cryptic self-incompatibility. In early snowmelt populations, seed production was pollen-limited and autogamous selfing was common. However, genetic analyses revealed that selfed progenies did not contribute to the maintenance of populations due to late-acting inbreeding depression.Large variations in seed-set and outcrossing rates among populations were caused by the timing of pollinator availability during the season and the cryptic self-incompatibility of this species. Despite the intensive pollen limitation in part of the early season, reproductive assurance by autogamous selfing was not evident. Under fluctuating conditions of pollinator availability and flowering structures, P. aleutica maintained the genetic composition by conspecific outcrossing.