Plant responses to a changing climate: linking leaf and global-scale analysis for future food security

到2050年，全球农业产量需要翻一番，以满足不断增长的人口需求和气候变化的挑战。不断变化的气候条件，包括气温上升、降水量变化更大和干旱，可能对保持作物高产和稳定的粮食供应造成压力。另一方面，假设其他因素不受限制，大气中二氧化碳水平的上升可能会导致作物生产力的提高，因为二氧化碳的增加可以促进植物光合作用的提高。不同作物或栽培品种适应水、温度或养分压力的能力不同，这表明特定农业系统的内在复原力，以及它们受气候变化影响的可能性和程度。了解当前和未来植物生长条件如何影响作物产量是确保粮食安全、调整作物选择和管理战略以及指导作物育种计划的一个主要优先事项。这方面的主要挑战是将实验室中可以在叶片水平上测量的植物行为与国家或全球范围内的植物行为联系起来，并预测在预测的气候条件下的未来行为。由于环境驱动因素在多个时空尺度上运作和相互作用，应对这一挑战将需要改变我们理解、监测和预测植物对压力的反应的方式。近年来，卫星观测彻底改变了空间生态学，使监测大空间尺度上的生态趋势成为可能，并从植物扩展到地球仪。日益精密的仪器和技术使科学家能够以前所未有的精确度从卫星上研究植被变化趋势对气候变化的反应。这些进展之所以能够取得，是因为传感器的发展、遗留卫星数据档案的增加以及太阳能诱导叶绿素荧光等新技术和新兴技术，这些技术已被证明与植物生产力密切相关。虽然仍处于起步阶段，但太阳能诱导的叶绿素荧光已显示出利用无人机到卫星远程监测作物生长的潜力。然而，这些遥感技术必须首先得到支持的过程为基础的了解遥感信号和植物特性之间的联系。在这项研究中，受控实验室实验将用于了解植物胁迫如何表现在叶片生化和结构特性的变化中，以及光学反射特征如何用于测量这些变化。然后，这些光学标记将用于“扩大”我们的观测，首先在实地规模上使用无人机技术，然后在国家和全球范围内使用卫星数据。这种关于作物健康的遥感数据将用于复杂的生物圈模型，以预测当前条件下和预测未来条件下的植物表现。这些方法相结合，将提供一个技术基础，在不同的规模，以充分利用现有的资源，作物改良的全貌。该研究的总体目标是评估国家和全球重要农作物在不同环境压力下保持生长和表现的能力。这项研究将采用先进的跨学科方法，使用受控生长室，新颖的遥感技术和植物科学方法，从叶子扩展到地球仪，并提供对未来作物可能面临的压力的逐步变化的理解。

Global agricultural production is required to double by 2050 to meet the demands of an increasing population and the challenges of a changing climate. Changing climatic conditions, including increasing temperatures, more variable precipitation, and drought are likely to put pressure on maintaining both high crop yields and a steady supply of food. On the other hand, assuming other factors are not limiting, rising atmospheric CO2 levels may lead to increased crop productivity, as the increased availability of carbon dioxide can promote enhanced rates of plant photosynthesis. The varying abilities of different crops or cultivars to adapt to water, temperature or nutrient pressures signifies the inherent resilience of a given agricultural system, and the likelihood and the degree to which they will be impacted by climate change. Understanding how current and future plant growth conditions affect crop yield is a major priority for ensuring food security, for adapting crop selection and management strategies and for guiding crop breeding programmes. The key challenge here is linking plant behaviour that can be measured at the leaf-level in the laboratory, to plant behaviour at the national or global scale, and predicting future behaviour under forecasted climate conditions. As environmental drivers operate and interact at multiple temporal and spatial scales, addressing this challenge will require transforming how we understand, monitor and predict plant responses to stress.Observations from satellites have revolutionised spatial ecology in recent years; making it possible to monitor ecological trends over large spatial scales, and to scale from the plant to the globe. Increasingly sophisticated instruments and techniques allow scientists to examine changing vegetation trends in response to climate change from satellites at unprecedented levels of accuracy. These advances have been made possible by sensor developments, an increasing archive of legacy satellite data, and new and emerging techniques such as solar-induced chlorophyll fluorescence, which has been shown to be closely related to plant productivity. Whilst still in its infancy, solar-induced chlorophyll fluorescence has shown potential to remotely monitor crop growth, using drones through to satellites. However, these remote sensing techniques must first be underpinned by a process-based understanding of the connections between the remote sensing signal and plant characteristics. In this research, controlled laboratory experiments will be used to understand how plant stress manifests in changes to the leaf biochemical and structural properties, and in turn, how optical reflectance signatures, can be used to measure these changes. These optical markers will then be used to 'scale up' our observations, first using drone technology at the field scale, and then and at national and global scales using satellite data. This remote sensing data on crop health will be used within sophisticated biosphere models to predict plant performance under current conditions and forecasted future conditions. These approaches in combination will provide a technological basis for a complete picture at different scales, to fully exploit the resources available for crop improvement. The overarching goal of the research is to assess the ability of nationally and globally important agricultural crops to maintain their growth and performance under different environmental stresses. This research will deploy a cutting-edge, cross-disciplinary approach using controlled growth chambers, novel remote sensing techniques and plant science methods to scale from the leaf to the globe, and provide a step-change understanding in the future pressures that crops may face in light of a changing climate and their underlying resilience.