Introduced populations often experience lag times before invasion, but the mechanisms constraining rapid expansions of introduced populations are unclear. Solidago altissima is a North American native plant with highly invasive Japanese populations and introduced Australian populations that are not invasive despite the climatic and ecological suitability of the region. By contrasting Australian with Japanese populations, we tested the hypothesis that Australian population growth is limited by a lack of long-distance dispersal via seeds owing to a limited number of compatible mates. In the field, Australian populations rarely produced viable seeds. A cross-pollination experiment found that Australian plants are fertile, yet lack compatible mates within Australia. Genetic analysis revealed that Australian individuals descend from a small set of self-incompatible genetic clones, which explains the negligible seed set within Australia. Our results show that low genetic diversity, leading to mate incompatibility, inhibits invasiveness of Australian S. altissima, and provides compelling evidence for genetic, rather than ecological, factors constraining invasion in Australia.

中文翻译：

---

缺乏遗传相容的配偶会限制杂草的扩散。

引入的种群通常在入侵之前经历滞后时间，但是限制引入种群快速扩张的机制尚不清楚。一枝黄花（Solidago altissima）是北美本土植物，具有高度侵袭性的日本种群，并且引入了尽管该地区的气候和生态适宜性仍无侵害性的澳大利亚种群。通过比较澳大利亚人和日本人的人口，我们检验了以下假设：由于可交配的伴侣数量有限，澳大利亚人缺乏通过种子进行远距离散播而受到限制。在田间，澳大利亚人口很少生产可行的种子。异花授粉实验发现，澳大利亚的植物肥沃，但在澳大利亚内部却缺乏相容的伴侣。遗传分析表明，澳大利亚人来自一小群自我不相容的基因克隆，这解释了澳大利亚境内种子数量可忽略不计的原因。我们的结果表明，低遗传多样性导致配偶不亲和，抑制了澳大利亚S. altissima的入侵，并为约束澳大利亚入侵的遗传而非生态因素提供了令人信服的证据。