Plant Tolerance of Herbivory: Fitness Costs and Mechanisms

小行星9527900 植物对疾病或草食动物的反应可以是抵抗，从而降低损害的程度，或者它们可以通过减少其对繁殖的影响来容忍损害。 很少有人致力于了解植物如何忍受或补偿损害。 然而，许多植物生态学家坚持认为，补偿损害是植物对植食性反应的一个重要机制。 最近的研究揭示了自然植物种群中耐受性的遗传变异，以及与耐受性相关的权衡：当植物在存在损害的情况下表现相对较好时，它们的兄弟姐妹在无损害的环境中表现相对较差。 这项建议描述了两个主要的实验，旨在探索机制的这种权衡野生芜菁芥菜，芜菁。 为了测量耐受性，将半同胞暴露于由昆虫和人工手段产生的损伤的仔细控制的水平和时间。 这些操作将在各种环境中进行，以确定哪些环境因素影响基因型补偿损害的能力。 定量遗传分析将被用来测试两个假设：H1：宽容是更昂贵的比电阻，因为宽容的成本与主要的生活史权衡;和H2：宽容的成本是由之间的权衡能力，以补偿损害和竞争能力。 这项研究的结果将大大提高对植物如何应对食草动物和病原体的理解。 此外，由于耐受性和补偿性生长已被公认为重要的农艺性状，这项研究将提供重要的见解，以权衡可能涉及这些性状育种到作物品种。

9527900 Simms Plants may respond to disease or herbivory either with resistance, which reduces the level of damage, or they may tolerate damage by reducing its effect on reproduction. Little effort has been devoted to understanding how plants tolerate or compensate for damage. Nevertheless, many plant ecologists have maintained that compensating for damage is an important mechanism by which plants respond to herbivory. Recent studies have revealed genetic variation for tolerance within natural plant populations, as well as trade-offs associated with tolerance: when plants do relatively well in the presence of damage, their siblings do relatively poorly in a damage-free environment. This proposal describes two major experiments designed to explore mechanisms underlying this trade-off in the wild turnip mustard, Brassica rapa. To measure tolerance, half sibs will be exposed to carefully controlled levels and timing of damage produced by both insects and artificial means. These manipulations will be performed in various environments to determine what environmental factors influence the ability of genotypes to compensate for damage. Quantitative genetic analyses will be used to test two hypotheses: H1: Tolerance is more costly than resistance because costs of tolerance are associated with major life-history trade-offs; and H2: The cost of tolerance is caused by a trade-off between ability to compensate for damage and competitive ability. Results from this study will significantly improve understanding of how plants respond to herbivores and pathogens. Furthermore, as tolerance and compensatory growth have become recognized as important agronomic traits, this study will provide important insights as to what trade-offs might be involved in breeding these traits into crop varieties.