Phenotypic plasticity rather than locally adapted ecotypes allows the invasive alligator weed to colonize a wide range of habitats
Phenotypic plasticity rather than locally adapted ecotypes allows the invasive alligator weed to colonize a wide range of habitats
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DOI：
10.1007/s10530-006-9029-1
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发表时间：
2007-04-01
影响因子：
2.9
通讯作者：
Song, Zhi-Ping
中科院分区：
文献类型：
--
作者：
Geng, Yu-Peng;Pan, Xiao-Yun;Song, Zhi-Ping
表型可塑性和局部适应的生态型都可能有助于入侵物种在广泛的生境中取得成功。在这里，我们进行了常见的花园实验和分子标记分析，以验证两种替代假说在侵袭性鳄鱼草中的存在，这种杂草同时定居在水生和陆地生境中。利用ISSR标记对中国南部3对水生与陆生种群的90个个体进行了中性基因座的群体分化分析。建立了两个模拟水生和陆地生境的普通花园，以研究种群在数量性状上的分化。在中性座位和数量性状上均未发现群体分化的证据。大多数个体具有相同的ISSR基因。同时，来自不同栖息地的植物在两个共同的花园中表现出相似的反应规范。特别是，与水生环境相比，陆地环境中的植物向地下根分配的生物量要多得多，因为在陆地环境中，由于周期性或偶然的干扰，鳄鱼杂草可能会失去部分或全部地上芽。来自分子标记分析和普通花园实验的联合证据支持可塑性假说而不是生态型假说来解释鳄鱼杂草在广泛的生境中的适应性。
Both phenotypic plasticity and locally adapted ecotypes may contribute to the success of invasive species in a wide range of habitats. Here, we conducted common garden experiments and molecular marker analysis to test the two alternative hypotheses in invasive alligator weed (Alternanthera philoxeroides), which colonizes both aquatic and terrestrial habitats. Ninety individuals from three pairs of aquatic versus terrestrial populations across southern China were analyzed, using inter simple sequence repeat (ISSR) marker, to examine population differentiation in neutral loci. Two common gardens simulating aquatic and terrestrial habitats were set up to examine population differentiation in quantitative traits. We found no evidence of population differentiation in both neutral loci and quantitative traits. Most individuals shared the same ISSR genotype. Meanwhile, plants from different habitats showed similar reaction norms across the two common gardens. In particular, plants allocated much more biomass to the belowground roots in the terrestrial environment, where alligator weed may lose part or all of the aboveground shoots because of periodical or accidental disturbances, than those in the aquatic environment. The combined evidence from molecular marker analysis and common garden experiments support the plasticity hypothesis rather than the ecotype hypothesis in explaining the adaptation of alligator weed in a wide range of habitats.