Tiébré Marie-Solange, Vanderhoeven Sonia, Saad Layla, Mahy Grégory
Laboratory of Ecology, Gembloux Agricultural University, Passage des Déportés 2, B-5030 Gembloux, Belgium.
Ann Bot. 2007 Jan;99(1):193-203. doi: 10.1093/aob/mcl242.
The knotweed complex, Fallopia spp. (Polygonaceae), belongs to the most troublesome invasive species in Europe and North America. Vegetative regeneration is widely recognized as the main mode of reproduction in the adventive regions. However, the contribution of sexual reproduction to the success of these invasive species has only been detailed for the British Isles. An examination was made as to how hybridization may influence the sexual reproduction of the complex in Belgium and to determine how it may contribute to the dispersal of the species.
Studies were made of floral biology, reproductive success, seed rain, seed bank, germination capacity, seedling survival and dispersal capacity in order to characterize the reproductive biology of the species. Moreover, chromosome counts and flow cytometry were used to assess the hybrid status of seedlings produced by sexual reproduction.
In the area investigated, extensive sexual reproduction by hybridization within the complex, including one horticultural species, was demonstrated. A small percentage of seeds may be dispersed outside the maternal clone (>16 m) allowing the formation of genetically differentiated individuals. Seed germination was possible even after a winter cold period.
The extensive sexual reproduction by hybridization could further contribute to the dramatic invasive success of knotweeds in Belgium and should not be underestimated when considering control and management measures.
虎杖复合体，何首乌属（蓼科），是欧洲和北美最棘手的入侵物种之一。营养繁殖被广泛认为是其在入侵地区的主要繁殖方式。然而，仅对不列颠群岛详细研究了有性繁殖对这些入侵物种成功入侵的贡献。本研究旨在探讨杂交如何影响比利时该复合体的有性繁殖，并确定其如何促进该物种的扩散。
通过对花生物学、繁殖成功率、种子雨、种子库、发芽能力、幼苗存活和扩散能力进行研究，以表征该物种的繁殖生物学。此外，利用染色体计数和流式细胞术评估有性繁殖产生的幼苗的杂交状态。
在所研究的区域，证实了该复合体内通过杂交进行广泛的有性繁殖，其中包括一个园艺品种。一小部分种子可能会扩散到母本克隆体之外（>16米），从而形成基因分化的个体。即使经过一个冬季的寒冷期，种子仍有可能发芽。
杂交导致的广泛有性繁殖可能进一步促使虎杖在比利时成功入侵，在考虑控制和管理措施时不应低估这一点。
