The potential for genetic assimilation of a native dandelion species, Taraxacum ceratophorum (Asteraceae), by the exotic congener T-officinale
The potential for genetic assimilation of a native dandelion species, Taraxacum ceratophorum (Asteraceae), by the exotic congener T-officinale
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DOI：
10.3732/ajb.91.5.656
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发表时间：
2004-05-01
影响因子：
3
通讯作者：
Brock, MT
中科院分区：
文献类型：
--
作者：
Brock, MT
外来植物物种可以通过不对称杂交和随后的回交，即所谓的遗传同化，威胁到密切相关的本地同类植物。我探讨了这一过程的初始阶段，在蒲公英ceratophorum（菊科），本地高山植物，和入侵无融合生殖T。officinale。在科罗拉多中部，七个T。ceratophorum种群均与T. officinale。在宾夕法尼亚山的一个大的人口，调查进一步显示，开花物候和来访的昆虫类群几乎完全重叠的蒲公英物种。这些结果表明，异源花粉传递是可能的。杂交试验表明，7：ceratophorum是专性异交种，种间人工授粉结实率为37.3%。然而，对F1后代的分子分析表明，只有33.2%的发芽种子是杂交种;其余的是自交不亲和性（导师效应）崩溃产生的自交后代。虽然导师效应有助于减少杂种的产生，但杂交的不对称方向创造了T. ceratophorum，T. officinale。
Exotic plant species can threaten closely related native congeners through asymmetric hybridization and subsequent backcrossing, the process known as genetic assimilation. I explore the initial stages of this process in Taraxacum ceratophorum (Asteraceae), the native alpine dandelion, and the invasive apomict T. officinale. In central Colorado, seven T. ceratophorum populations all occur in sympatry with T. officinale. In one large population on Pennsylvania Mountain, surveys further revealed that flowering phenologies and visiting insect taxa overlap almost completely for both Taraxacum species. Together these results indicated that heterospecific pollen transfer is likely. Crossing experiments showed that 7: ceratophorum is an obligate outcrosser, and interspecific hand pollinations resulted in 37.3% seed set. However, molecular analysis of the F1 offspring indicated that only 33.2% of germinating seeds were hybrids; the remainder were selfed offspring produced from a breakdown in self-incompatibility (the mentor effect). Although the mentor effect helps reduce the production of hybrids, the asymmetrical direction of hybridization creates the potential for genetic assimilation of T. ceratophorum by T. officinale.