DISSERTATION RESEARCH: Carbon allocation strategies in understory native and invasive woody plants

美国东部天然林最大的管理问题之一是来自欧洲和亚洲的观赏灌木的入侵。这些植物在资源方面胜过当地物种，减少了植物物种的多样性，并改变了森林养分的循环。这个项目将探索本地和入侵灌木物种之间的能源使用差异，以促进我们对外来植物何时以及为什么将本地植物排除在外的理解。研究结果将帮助森林管理者在面对环境变化时做出最好地保护美国森林的决策。该项目将支持博士生的研究和培训，扩大学生的实验和分析技能。来自代表性不足群体的本科生将参与实践研究；通过这种参与，研究将培养新一代具有批判性思维的年轻科学家。该项目描述了生长在落叶森林林下的原生和入侵木本植物的碳分配模式。它将评估增长率和碳储存分配之间的关系，以及国防分配如何调节这种关系。研究人员将测试一个普遍的假设，即入侵植物为生长分配了更多的碳，而牺牲了存储分配，以便在资源竞争中胜过本地植物。淀粉和单糖形式的储存化合物对于组织损伤的恢复和霜冻事件的保护至关重要。初步数据显示，入侵物种的生长速度更快，对去叶的反应也会产生更多的叶子，但目前尚不清楚这是否以失去促进生存的储存化合物为代价。将在一系列本地和入侵物种的叶片上进行昆虫取食实验，以评估物理和化学防御的分配，冻结实验将阐明不同物种的茎淀粉和糖浓度之间的关系以及它们耐受低温的能力。这些活动将检验这样一个假设，即入侵物种比本地物种拥有更低的碳储存和防御分配，这种差异导致对叶片移除和冰冻事件的低存活率，以及对草食动物摄食的低抵抗力。

One of the largest management concerns in natural forests of the Eastern U.S. is the invasion of ornamental shrubs from Europe and Asia. These plants outcompete native species for resources, reducing plant species diversity and altering the cycling of forest nutrients. This project will explore differences in energy use between native and invasive shrub species to advance our understanding of when and why exotic plants will exclude native plants. Research findings will help forest managers make decisions that will best protect U.S. forests in the face of environmental change. The project will support the research and training of a doctoral student, expanding the student's experimental and analytical skills. Undergraduate students from underrepresented groups will participate in hands-on research; through this engagement, the research will foster a new generation of critically thinking young scientists. This project characterizes carbon allocation patterns in native and invasive woody plants growing in deciduous forest understories. It will evaluate the relationship between growth rates and carbon storage allocation, and how allocation to defense mediates this relationship. Researchers will test the general hypothesis that invasive plants allocate more carbon toward growth at the expense of storage allocation in order to outcompete native plants for resources. Storage compounds, in the form of starches and simple sugars, are critical for recovery from tissue damage and protection from frost events. Preliminary data show that invasive species have higher growth rates and produce more leaves in response to leaf removal, but it is unknown whether this comes at a loss of storage compounds that promote survival. An insect feeding experiment on a range of native and invasive species' leaves will be carried out to assess allocation to physical and chemical defenses, and a freezing experiment will elucidate the relationship between stem starch and sugar concentrations in different species and their ability to tolerate cold temperatures. These activities will test the hypothesis that invasive species possess lower carbon storage and defense allocation than native species, and that this difference leads to lower survival in response to leaf removal and freezing events, and lower resistance to herbivore feeding.