Understanding intraspecific variation in plant defense across resource gradients

植物通过在叶子和树枝上的刺中注入毒素来保护自己免受饥饿动物的伤害。它们还有很多其他的保护自己的方法。生态学家长期以来一直想知道，为什么不同种类的植物采取截然不同的保护策略。为什么没有最好的办法呢？即使是同一物种的不同个体也会以不同的方式保护自己。因此，生态学的一个主要挑战是弄清楚植物防御差异的原因和后果。一种观点认为，在生长速度不快的地方，植物可以将更多的能量用于防御。相比之下，在有大量水分和营养的地方，植物可以快速生长和繁殖——生命是好的，所以它们不需要那么多的防御。参与这个项目的科学家将检验这个想法。他们将研究同一物种的不同个体在压力大的地区和物质丰富的地区生长时如何改变它们的防御策略。他们将通过测量这些植物对昆虫的美味程度来测试这些防御措施的效果。研究结果可能揭示保护农作物免受害虫侵害的新策略。研究人员将让高中生和大学生参与这个项目，训练他们如何做科学研究。此外，公众将通过各种自然历史和保护项目参与其中。该项目涉及在8个高资源环境和8个低资源环境中复制种群的6种共生原生草地植物相互移植到每个区域的公共花园中。资源（降雨）也将在一个位于低资源区域的普通花园中进行操纵，以评估植物生长和防御对非生物因子的响应在多大程度上是可塑的。草食动物丰度和草食动物对植物适应性的影响（通过昆虫减少实验获得）将在两个资源区域包含焦点物种的种群中进行量化。总的来说，这些实验将评估资源环境如何影响：1)物种内的生长和防御（包括耐受性和抗性）进化和可塑性；2)种群间生长与防御呈正相关；3)昆虫食草性丰度及其对植物适应性的影响。最终，采用的多物种方法将有助于调和物种之间和物种内部经常观察到的不同生长-防御关系。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants defend themselves from hungry animals by putting poisons in their leaves and thorns on their branches. There are many other ways they protect themselves, too. Ecologists have wondered for a long time why different species of plants adopt very different strategies of protection. Why wouldn't there be one best way? Even different individuals of the same species defend themselves differently. Thus, a major challenge in ecology is to figure out the causes and consequences of differences in plant defense. One idea is that plants in places where they can't grow fast, can invest more energy in defense. In contrast, plants in places with lots of water and nutrients can grow and reproduce quickly -- life is good, so they don't need as much defense. Scientists with this project will test that idea. They will look at how different individuals of the same species may change their strategies of defense when grown in stressful areas and areas of plenty. They will test how well the defenses work by measuring how tasty the plants are to insects. Results may reveal new strategies for protection of farm crops from insect pests. The researchers will involve high school and college students in the project, training them how to do science. Also, the public will be engaged through various natural history and conservation programs.This project involves reciprocally transplanting six co-occurring native grassland plant species from populations replicated within eight high- and eight low-resource environments into common gardens located in each region. Resources (rainfall) will also be manipulated in a common garden located in the low-resource region to evaluate the extent to which responses of plant growth and defense to abiotic factors are plastic. Herbivore abundance and the impacts of herbivores on plant fitness (accessed via insect-reduction experiments) will be quantified within populations containing the focal species across the two resource regions. Collectively, these experiments will evaluate how the resource environment influences: 1) growth and defense (both tolerance and resistance) evolution and plasticity within species; 2) positive growth and defense correlations across populations, and 3) insect herbivore abundance and the impacts of herbivory on plant fitness. Ultimately, the multispecies approach employed will help to reconcile the different growth-defense relationships often observed among vs. within species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.