Evolution of senescence in plants

植物衰老的进化

• 批准号: RGPIN-2021-02967
• 负责人: Laird, Robert
• 金额: $ 3.42万
• 依托单位: University of Lethbridge
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=744778
• 关键词: Evolution; senescence; plants

Senescence, known colloquially as `aging', is the progressive deterioration of individuals leading to decreased rates of survival and reproduction in old age. Senescence is extremely common in diverse organisms including humans, other animals, plants, and even fungi and bacteria. Theory predicts that in addition to age-related declines in survival and reproduction, we should also expect declines in offspring quality. Yet most work on senescence ignores these parental age effects, implicitly assuming that all offspring are of equal quality. This suggests that current approaches underestimate evolutionarily favoured rates of senescence, providing opportunities for innovative research. The long-term goal of my research program is to develop and test evolutionary theories of senescence with a focus on parental age effects. My team combines theory, field, and lab work, and uses floating aquatic plants in the genus Lemna as a model system. Four major objectives support my long-term goal: 1. Test whether offspring of old parents are less stress tolerant than those of young parents. Experiments will focus on three important stressors: salinity, high temperatures, and pH. We will determine whether advanced parental age exacerbates negative effects of stress on offspring. 2. Test whether parental age effects occur in wild plants. Plants will be grown in ponds using floating platforms to determine whether parental age effects observed in the lab also occur in nature, or if they are simply a result of benign lab conditions. 3. Test whether parental age effects alter population growth. We will develop extensions of classic population growth models to incorporate parental age effects. We will then test whether including parental age effects in population growth models improves their predictive power. 4. Test whether parental age effects occur at the whole-clone level. As Lemna is clonally reproducing, prior studies have focused on senescence at the level of physiological individuals. We will manipulate the `effective age' of whole clones (using temperature treatments to vary the number of clonal generations) to test whether older clones produce lower-fitness offspring than younger ones. Senescence is a central topic in ecology and evolution. My ongoing research demonstrates the necessity of considering parental age effects to understand the evolution of senescence. The proposed work builds on this foundation by linking parental age effects to diverse topics such as stress biology, modes of reproduction, and population growth. The discoveries delivered by my research program will be valuable to demographers, evolutionary biologists, and ecologists. Due to my unified conceptual focus, my research will be relevant to understanding senescence in general, not just in plants. Additionally, this research will help advance-and provide training in-the field of biodemography, a discipline of increasing socio-economic importance due to Canada's aging population.

衰老，俗称“衰老”，是指个体的逐渐退化，导致老年时存活率和生殖率下降。衰老在包括人类、其他动物、植物、甚至真菌和细菌在内的各种生物体中非常常见。理论预测，除了与年龄相关的生存和繁殖能力下降外，我们还应该预料到后代质量的下降。然而，大多数关于衰老的研究都忽略了这些父母年龄的影响，含蓄地假设所有的后代都是同等质量的。这表明，目前的方法低估了进化上有利的衰老速度，为创新研究提供了机会。我的研究计划的长期目标是发展和测试衰老的进化理论，重点是父母的年龄效应。我的团队结合了理论，实地和实验室工作，并使用浮萍属的漂浮水生植物作为模型系统。 四个主要目标支持我的长期目标：1。测试年老父母的后代是否比年轻父母的后代更不耐压力。实验将集中在三个重要的压力源：盐度，高温和pH值。我们将确定是否先进的父母年龄加剧了压力对后代的负面影响。2.测试野生植物中是否存在亲本年龄效应。植物将在使用浮动平台的池塘中生长，以确定在实验室中观察到的亲本年龄效应是否也发生在自然界中，或者它们是否只是良性实验室条件的结果。3.测试父母年龄效应是否会改变人口增长。我们将扩展经典的人口增长模型，以纳入父母的年龄效应。然后，我们将测试在人口增长模型中包括父母年龄效应是否会提高其预测能力。4.测试亲本年龄效应是否发生在整个克隆水平。由于浮萍是克隆繁殖，以前的研究集中在生理个体水平的衰老。我们将操纵整个克隆的“有效年龄”（使用温度处理来改变克隆世代的数量），以测试年长的克隆是否比年轻的克隆产生更低适应度的后代。衰老是生态学和进化论的中心课题。我正在进行的研究表明，考虑父母年龄的影响，以了解衰老的演变的必要性。拟议的工作建立在这个基础上，通过将父母年龄效应与压力生物学，繁殖模式和人口增长等不同主题联系起来。我的研究项目所带来的发现将对人口统计学家、进化生物学家和生态学家有价值。由于我统一的概念重点，我的研究将与理解一般衰老有关，而不仅仅是植物。此外，这项研究将有助于推进生物人口学领域，并提供培训，这是一门由于加拿大人口老龄化而日益重要的社会经济学科。