State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing, China.
College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
Ecol Appl. 2024 Jan;34(1):e2903. doi: 10.1002/eap.2903. Epub 2023 Aug 30.
Rapid adaptive evolution and phenotypic plasticity are two mechanisms that often underlie invasiveness of alien plant species, but whether they can co-occur within invasive plant populations under altered environmental conditions such as nitrogen (N) enrichment has seldom been explored. Latitudinal clines in plant trait responses to variation in environmental factors may provide evidence of local adaptation. Here, we inferred the relative contributions of phenotypic plasticity and local adaptation to the performance of the invasive plant Ambrosia artemisiifolia under different soil N levels, using a common garden approach. We grew A. artemisiifolia individuals raised from seeds that were sampled from six invasive populations along a wide latitudinal cline in China (23°42' N to 45°43' N) under three N (0, 5, and 10 g N m ) levels in a common garden. Results show significant interpopulation genetic differentiation in plant height, number of branches, total biomass, and transpiration rate of the invader A. artemisiifolia across the N treatments. The populations also expressed genetic differentiation in basal diameter, growth rate, leaf area, seed width, root biomass, aboveground biomass, stomatal conductance, and intercellular CO concentration regardless of N treatments. Moreover, plants from different populations of the invader displayed plastic responses in time to first flower, hundred-grain weight, net photosynthetic rate, and relative biomass allocation to roots and shoots and seed length under different N treatments. Additionally, individuals of A. artemisiifolia from higher latitudes grew shorter and allocated less biomass to the roots regardless of N treatment, while latitudinal cline (or lack thereof) in other traits depended on the level of N in which the plants were grown. Overall, these results suggest that rapid adaptive evolution and phenotypic plasticity in the various traits that we quantified may jointly contribute to invasiveness of A. artemisiifolia under different levels of N availability. More broadly, the results support the idea that phenotypic plasticity and rapid adaptive evolution can jointly enable invasive plants to colonize a wide range of environmental conditions.
快速适应进化和表型可塑性是外来植物物种入侵的两个主要机制，但在氮（N）富集等环境条件改变下，它们是否能够在入侵植物种群中共存，这一问题很少被探讨。植物对环境因子变化的性状响应在纬度上的梯度变化可能为局部适应提供证据。在这里，我们使用了一种共同培养的方法，推断了表型可塑性和局部适应对入侵植物豚草在不同土壤 N 水平下表现的相对贡献。我们从中国（23°42'N 至 45°43'N）的六个入侵种群中采集了种子，并在一个共同的花园中，在三个 N（0、5 和 10 g N m ）水平下，对这些种子培育的个体进行了生长。结果表明，在 N 处理下，植物高度、分枝数、总生物量和蒸腾速率在入侵植物豚草的种群间存在显著的遗传分化。这些种群在基部直径、生长率、叶面积、种子宽度、根生物量、地上生物量、气孔导度和胞间 CO 浓度上也表现出遗传分化，而与 N 处理无关。此外，在不同 N 处理下，入侵植物的不同种群的个体在首次开花时间、百粒重、净光合速率以及根系和地上部分相对生物量分配和种子长度上表现出可塑性反应。此外，无论 N 处理如何，来自较高纬度的个体的 A. artemisiifolia 生长得更矮，分配给根部的生物量更少，而其他性状的纬度梯度（或缺乏）则取决于植物生长的 N 水平。总的来说，这些结果表明，我们量化的各种性状的快速适应进化和表型可塑性可能共同促进了 A. artemisiifolia 在不同 N 供应水平下的入侵性。更广泛地说，这些结果支持了这样一种观点，即表型可塑性和快速适应进化可以共同使入侵植物能够在广泛的环境条件下进行殖民化。
