Dynamics of a Native Iris-Herbivore Association: Effects of Salinity, Herbivory, and Genetic Variation

这个项目将调查在一系列盐分条件和食草性条件下生长的本地虹膜种群中不同类型植物胁迫之间的相互作用。盐分和食草性都是植物逆境的重要来源，都能诱导脱落酸(ABA)和茉莉酸(JA)的产生。这些激素在个体植物中的产生差异似乎受到遗传因素的影响。胁迫诱导反应的大小直接影响植物的生长繁殖以及对食草动物攻击的抗性。该项目将野外实验与实验室分析相结合，以1)检验植物激素诱导与虹膜和食草动物性能之间的关系，2)量化虹膜和食草动物种群中的基因流和遗传结构，以及3)确定虹膜和虹膜食草动物是否局部适应它们的微环境。ABA和JA都是生长调节剂，影响植物对环境和食草动物介导的胁迫的耐受性。因此，该项目的成果具有重要的经济意义。这项研究将首次确定胁迫诱导的ABA和JA在自然植物种群中的浓度和波动，从而促进我们对植物激素在植物逆境耐受性中所起作用的总体理解。植物对病虫害的抗性既有遗传基础，也有环境基础。通过量化盐分胁迫和确定植物和食草动物种群的遗传结构，本研究可以确定哪些植物基因型与对盐分和草食胁迫的耐受性和敏感性有关，以及哪些植食性基因类型与毒力有关。然后，这些信息可以应用于压力耐受性是重要组成部分的管理型系统。

This project will investigate the interaction between different types of plant stress in a population of native iris growing under a range of salinity conditions and herbivory. Both salinity and herbivory can be important sources of plant stress, and both can induce the production of abscisic acid (ABA) and jasmonic acid (JA). Variation in the production of these hormones among individual plants appears to be genetically influenced. The magnitude of the stress induction response can directly affect plant growth and reproduction as well as resistance to herbivore attack. This project combines field experiments with laboratory analyses to 1) examine the relationship between phytohormone induction and iris and herbivore performance, 2) quantify gene flow and genetic structure in the iris and herbivore populations, and 3) determine if iris and iris herbivores are locally adapted to their microenvironment. Both ABA and JA are growth regulators that influence plant tolerance to environmental and herbivore-mediated stress. Thus the results of this project have important economic implications. This study will be the first to determine the concentrations and fluctuations of stress-induced ABA and JA in a natural plant population, and can therefore advance our general understanding of the role played by phytohormones in plant stress tolerance. Plant resistance to pests and pathogens is both genetically and environmentally based. By quantifying salinity stress and determining the genetic structure of the plant and herbivore populations, this study can determine what plant genotypes are associated with tolerance and susceptibility to salinity and herbivory stress, as well as the herbivore genotypes associated with virulence. This information can then be applied to managed systems in which stress tolerance is an important component.