Does physiological innovation change the fundamental relationships between growth and survival?

生理创新是否改变了生长与生存之间的基本关系？

• 批准号: NE/N003152/1
• 负责人: Colin Osborne
• 金额: $ 76.37万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FN003152%2F1
• 关键词: Does; physiological; innovation; change; fundamental

"Live fast, die young" famously describes the wild excesses of rock stars and Hollywood actors, but also encapsulates an important biological principle. Animals and plants that grow and reproduce quickly are more likely to be killed by natural enemies or environmental extremes. We usually explain this biological trade-off in terms of energy: more energy spent on growth means less energy invested in defence against enemies, the capture of essential resources, or into stores for surviving adverse conditions. A logical extension of this explanation is that, if the same growth could be achieved using less energy, more would be available for defence, resource capture and storage, thereby increasing survival. However, this prediction remains untested, despite its central importance for biology.The evolution of C4 photosynthesis in more than seventy plant lineages has increased the efficiency of photosynthetic energy conversion at high light and hot temperatures, in comparison with the ancestral C3 type of photosynthesis. To understand how this increase in photosynthetic efficiency influences growth, we have developed an experimental approach capable of comparing growth among hundreds of plant species in the same environmental conditions. We have discovered that, as well as a direct physiological effect of C4 photosynthesis in promoting faster growth, C4 leaves are unexpectedly less dense than C3 ones, further increasing growth efficiency. This allows C4 plants to be larger, with more growth invested in roots, which leads us to hypothesize that they may be able to accumulate greater storage, and have better access to water during drought than their C3 counterparts. Together, these hypothesized effects are expected to increase plant survival following repeated defoliation and drought events. If supported by experimental evidence, these ecological differences between C3 and C4 plants would have important global scale implications for the responses of plant communities to environmental change and land management.We propose to test these hypothesis using three large comparative experiments, capitalizing on our recent advances in developing high-throughput experimental screening methods. We are able to measure growth, allocation to roots verses shoots, storage and survival on thousands of plants in the same experimental set-up, and have developed novel statistical methods to analyze the large resultant datasets. We are also the first group to successfully apply metabolomic methods to identify and quantify storage compounds across multiple wild plant species. Our strategy for the proposed work will be to combine these approaches, investigating survival of experimentally imposed drought or repeated defoliation in seventy ecologically important grass species, representing seven independent evolutionary origins of C4 photosynthesis and their C3 sister taxa. Alternative hypothesized survival mechanisms will be tested by using plants of different ages to manipulate size. Since C4 photosynthesis also has a direct physiological effect on plant water use, by reducing stomatal aperture, we will make detailed measurements of plant hydraulics during the drought experiment. Findings from the three experiments will allow us to test the relative importance to survival of greater storage, deeper rooting, lower plant water use, and greater plant size in C4 then C4 species, and to gain a holistic understanding of the system. The work will enhance our mechanistic understanding of how a major physiological innovation changed growth-survival relationships and enabled plants to explore new phenotypic space. Throughout the project, we will work with mathematical modelers to ensure that the experiments will generate data that are useful for developing improved models of how global vegetation stores carbon and influences climate.

“活得快，死得早”这句名言描述了摇滚明星和好莱坞演员的疯狂行为，但也概括了一个重要的生物学原理。快速生长和繁殖的动植物更有可能被天敌或极端环境杀死。我们通常用能量来解释这种生物权衡：用于生长的能量越多，意味着用于防御敌人、获取重要资源或用于在不利条件下生存的储存的能量就越少。这种解释的逻辑延伸是，如果可以使用更少的能源实现相同的增长，则更多的能源将可用于防御、资源捕获和储存，从而提高生存率。然而，尽管这一预测对生物学至关重要，但它仍未得到检验。与祖先的 C3 类型光合作用相比，70 多个植物谱系中 C4 光合作用的进化提高了高光和高温下光合能量转换的效率。为了了解光合效率的提高如何影响生长，我们开发了一种实验方法，能够比较相同环境条件下数百种植物物种的生长情况。我们发现，除了 C4 光合作用促进更快生长的直接生理效应外，C4 叶子的密度出乎意料地低于 C3 叶子，进一步提高了生长效率。这使得 C4 植物变得更大，根部的生长量更大，这使我们推测它们可能能够积累更多的储存量，并且在干旱期间比 C3 植物更容易获得水分。总之，这些假设的影响预计将提高植物在反复落叶和干旱事件后的存活率。如果得到实验证据的支持，C3 和 C4 植物之间的这些生态差异将对植物群落对环境变化和土地管理的反应产生重要的全球范围影响。我们建议利用三个大型比较实验来检验这些假设，利用我们在开发高通量实验筛选方法方面的最新进展。我们能够在同一实验装置中测量数千种植物的生长、根与芽的分配、储存和存活，并开发出新颖的统计方法来分析大型结果数据集。我们也是第一个成功应用代谢组学方法来识别和量化多种野生植物物种的储存化合物的团队。我们拟议工作的策略是将这些方法结合起来，研究 70 种具有重要生态意义的草种在实验性干旱或反复落叶中的生存情况，代表 C4 光合作用及其 C3 姐妹类群的七个独立进化起源。将通过使用不同年龄的植物来操纵大小来测试替代假设的生存机制。由于C4光合作用对植物水分利用也有直接的生理影响，通过减小气孔孔径，我们将在干旱实验期间对植物水力学进行详细测量。这三个实验的结果将使我们能够测试 C4 物种中更大的储存量、更深的生根、更低的植物用水量和更大的植物尺寸对生存的相对重要性，并获得对该系统的整体了解。这项工作将增强我们对重大生理创新如何改变生长-生存关系并使植物能够探索新表型空间的机制理解。在整个项目中，我们将与数学建模人员合作，确保实验生成的数据有助于开发全球植被如何储存碳和影响气候的改进模型。

项目成果

Large seeds provide an intrinsic growth advantage that depends on leaf traits and root allocation

大种子提供了内在的生长优势，这取决于叶子性状和根部分配

• DOI: 10.1111/1365-2435.13871
• 发表时间: 2021
• 期刊: Functional Ecology
• 影响因子: 5.2
• 作者: Simpson K

The morphogenesis of fast growth in plants.

• DOI: 10.1111/nph.16892
• 发表时间: 2020-08
• 期刊: The New phytologist
• 作者: R. Wade;Patrick Seed;Eleanor McLaren;Ellie Wood;P. Christin;K. Thompson;M. Rees;C. Osborne