Institute of the Environment and Sustainability, University of California Los Angeles, 619 Charles E. Young Dr., Los Angeles, 90024, CA, USA.
Department of Ecology and Evolutionary Biology, University of Connecticut, 75 N. Eagleville Rd, Storrs, 06269, CT, USA.
Am J Bot. 2024 Nov;111(11):e16430. doi: 10.1002/ajb2.16430. Epub 2024 Nov 6.
To survive climate change and habitat loss, plants must rely on phenotypic changes in response to the environment, local adaptation, or migration. Understanding the drivers of intraspecific variation is critical to anticipate how plant species will respond to climate change and to inform conservation decisions. Here we explored the extent of local adaptation and phenotypic plasticity in Heteromeles arbutifolia, toyon, a species endemic to the California Floristic Province.
We collected leaves from 286 individuals across toyon's range and used seeds from 37 individuals to establish experimental gardens in the northern and southern parts of toyon's range. We measured leaf functional traits of the wild-collected leaves and functional and fitness traits of the offspring grown in the experimental gardens. We then investigated the relationships between traits and source environment.
Most traits we investigated responded plastically to the environment, and some traits in young seedlings were influenced by maternal effects. We found strong evidence that variation in leaf margins is a result of local adaptation to variation in temperature and temperature range. However, the source environment was not related to fitness traits or survival in the experimental gardens.
Our findings reiterate the adaptive role of toothed leaf margins in colder and more seasonally variable environments. Additionally, we provide evidence that fitness of toyon is not dependent on where they are sourced, and thus toyon can be sourced across its range for restoration purposes.
为了应对气候变化和栖息地丧失，植物必须依靠表型变化来适应环境、进行局部适应或迁移。了解种内变异的驱动因素对于预测植物物种对气候变化的反应以及为保护决策提供信息至关重要。在这里，我们探讨了加州特有物种 Heteromeles arbutifolia（玩具熊果）的局部适应和表型可塑性的程度。
我们从玩具熊果的分布范围内收集了 286 个个体的叶片，并从 37 个个体的种子中建立了实验花园，分别位于玩具熊果分布范围的北部和南部。我们测量了野生采集叶片的叶功能性状以及在实验花园中生长的后代的功能和适应性状。然后，我们研究了性状与源环境之间的关系。
我们研究的大多数性状对环境具有可塑性，一些幼苗的性状受到母本效应的影响。我们有强有力的证据表明，叶片边缘的变异是对温度和温度范围变化的局部适应的结果。然而，源环境与实验花园中的适应性状或存活率无关。
我们的研究结果再次强调了锯齿状叶片边缘在较冷和季节性变化较大的环境中的适应作用。此外，我们提供了证据表明，玩具熊果的适应能力并不取决于它们的来源地，因此可以在其分布范围内为恢复目的而获取玩具熊果。
