DISSERTATION RESEARCH: Local adaptation and fitness trade-offs in the California annual, Leptosiphon parviflorus

适应性研究对于理解自然生态系统的生物多样性和农业发展都至关重要。一个常见的观察是，生物体的特征不同，使它们独特地适合生活在特定的栖息地。这个过程被称为局部适应，通常被认为是适应性“权衡”的结果，即在一个环境中提高性能的特性在另一个环境中降低了性能。目前的研究探讨了适应性的权衡在一对当地适应人口的一年生野花，细管小花，生活在两个对比鲜明的土壤类型，砂岩和蛇纹石，在加州草原。这项研究有几个广泛的影响。首先，了解适应性特征如何促进生物多样性，以及它们在交替环境中是否具有适应性后果，对于预测物种如何应对环境变化非常重要。虽然人们认为植物可能会因气候变化而改变其分布范围，但重要的是要了解对特定土壤类型（如蛇纹石）的适应如何限制其合适的栖息地。此外，了解性状如何影响不同环境中的适应性对农业也有意义。育种者需要了解在一个环境中增加作物产量的性状是否会对另一个环境中的产量产生负面影响。通过这项研究将研究的许多生理特性是重要的农业特性，例如在劣质土壤上生存的能力，或在干旱时期生存的能力。增加对这些特征在不同生境中对生长和生存的影响的了解，可能会扩大适合耕种的地区。最后，该项目的合作PI通过NSF GK-12计划在一所农村中学工作，该计划旨在向K-12学生教授科学探究。该项目的成果将通过课程计划和研讨会介绍给学生和教师。砂岩土壤具有足够的营养水平，而蛇纹石土壤的重要植物营养素含量低，镁含量高，对植物有毒。此外，蛇纹岩土壤比砂岩土壤更容易干燥。 由于这些特性，许多独特的植物生活在蛇纹土中。虽然目前研究中的种群非常接近，但它们的花色和开花时间不同，这表明这些特征可能有助于适应性权衡。这项研究调查了这些性状对每种土壤类型的生长，生存和繁殖的影响，以及为什么在一种土壤类型中适应的性状会降低另一种土壤类型的性能。将使用几种方法。首先，在温室中进行实验性进化研究，用代表两种亲本基因组混合物的植物在两种类型的土壤上生长品系。5代后，为了确定温室实验品系的选择程度，将它们与对照非选择品系一起沿着生长在田间的两种生境中。如果植物在它们被选择的土壤上具有更高的适应性，而在相对于非选择系的外来土壤上具有更低的适应性，则对土壤类型的适应性导致适应性权衡。这些权衡的幅度可以测量，以确定是否适合优势在本土土壤上的大小相似的健身劣势在外国south.Interestingly，花的颜色似乎并不影响传粉者的访问，这表明它可能有助于通过对耐旱性或养分吸收的间接影响土壤适应。将使用从一系列异花授粉中产生的植物进一步研究花色，这些异花授粉将花色从一个种群中分离出来，并将其培育到另一个种群的遗传背景中。这使我们能够独立于其他特征来衡量这种特征的影响。来自蛇纹石种群的粉红色花色位点的植物将渗入砂岩种群的遗传背景中。使用这些植物，可以测量两种栖息地中花色的适合度效应，以确定由于这一单一性状而产生的权衡程度。此外，我们将探索花色基因影响其他性状的可能性，如水分利用效率和养分吸收使用这些线，因为它们涉及土壤耐受性和潜在的共享生化途径与花色素。

The study of adaptation is central both to understanding the biological diversity of natural ecosystems and to the development of agriculture. A common observation is that organisms differ in traits that make them uniquely suited to live in a particular habitat. This process, called local adaptation, is often thought to result from adaptive "trade-offs", where traits that improve performance in one environment reduce it in another. The current study examines adaptive trade-offs in a pair of locally adapted populations of an annual wildflower, Leptosiphon parviflorus, which lives on two contrasting soil types, sandstone and serpentine, in a California grassland. There are several broad impacts to this research. First, understanding how adaptive traits contribute to biological diversity and whether they have fitness consequences in alternate environments is important for predicting how species will respond to environmental change. Although it is believed that plants may shift their ranges as a result of climate change, it is important to understand how adaptation to a particular soil type, such as serpentine, can limit their suitable habitat. In addition, understanding how traits affect fitness in different environments has implications for agriculture. Breeders need to understand whether traits that increase crop yields in one environment can negatively impact yields in another environment. Many physiological traits that will be studied through this research are important agricultural traits, such as the ability to live on poor quality soils, or to survive periods of drought. Increased knowledge of the consequences of these traits on growth and survival in different habitats may expand suitable areas for farming. Finally, the co-PI for this project works in a rural middle school through the NSF GK-12 program, a program that aims to teach scientific inquiry to K-12 students. Results from this project will be introduced to students and teachers through lesson plans and workshops.Sandstone soils have adequate levels of nutrients, while serpentine soils are low in vital plant nutrients and have high levels of magnesium, which can be toxic to plants. In addition, serpentine soils dry out more easily than sandstone soils. Due to these characteristics, many unique plants live in serpentine soils. Although the populations in the current study are in close proximity, they differ in their flower color and flowering times, indicating that these traits may contribute to adaptive trade-offs. This research investigates the effects that these traits have on growth, survival and reproduction within each soil type, and why traits that are adaptive in one soil type decrease performance in the other. Several methods will be used. First, an experimental evolution study in the greenhouse with plants that represent a genomic mixture of the two parents, will grow lines on both types of soil. After 5 generations, to determine the extent of selection in the greenhouse experimental lines, they will be grown in both habitats in the field along with a control non-selected line. If plants have higher fitness on the soil from which they were selected and reduced fitness on the foreign soil relative to the non-selected line, then adaptation to soil type results in fitness trade-offs. The magnitude of these trade-offs can be measured to determine if fitness advantages on the home soil are similar in magnitude to fitness disadvantages on foreign soil.Interestingly, flower color does not appear to affect pollinator visitation, suggesting that it may contribute to soil adaptation through indirect effects on drought tolerance or nutrient uptake. Flower color will be studied further using plants produced from a series of cross-pollinations that have isolated the flower color from one population and bred it into the genetic background of the other. This allows us to measure effects of this trait independently of others. The plants with the pink flower color locus from the serpentine population will be introgressed into the genetic background of the sandstone population. With these plants, the fitness effects of flower color in both habitats can be measured to determine the magnitude of trade-offs due to this single trait. Furthermore, we will explore the possibility that the flower color gene affects other traits such as water use efficiency and nutrient uptake using these lines, as they are implicated in soil tolerance and potentially share biochemical pathways with floral pigments.