Collaborative Research: BTT EAGER: A wearable plant sensor for real-time monitoring of sap flow and stem diameter to accelerate breeding for water use efficiency

在不牺牲产量的情况下培育提高抗旱性的植物是世界各地育种工作的主要目标。然而，抗旱性和产量往往呈负相关。水分通过植物茎流向叶片的速率是解释不同植物品种之间耐旱性差异的关键变量。然而，目前用于测量这种流量的技术体积庞大，并且当它们长时间应用时可能会损坏植物;因此，它们不能在整个生长季节监测植物。此外，从电流传感器收集的数据需要测量阀杆尺寸，以便准确测量流速。 如果茎在实验过程中生长，这些测量可能会引入误差。该项目开发了一种可穿戴式植物传感器，可以在许多环境和基因型中准确长期量化流量。大量的低成本传感器可以部署在育种计划中，从而能够直接评估品系。 从这些品系中，可以鉴定出控制不同环境条件下液流速率变化的特定遗传基因座。同样，来自这些传感器的数据可以用于基因组预测模型，该模型在资源田间试验投资之前优先考虑新的育种品系。这项研究将通过为工程和植物科学交叉领域的下一代研究人员提供研究机会来促进劳动力发展。该合作项目将整合传感器，微系统，纳米材料和植物科学的进步，以实现一种新的液流测量方法，最终推进功能基因组学研究和耐旱作物的育种。我们的目标是开发一种可穿戴植物传感器，用于长期、准确且经济实惠地监测整个生长季节的树液流动。传感器设计允许微尺度液流感测单元与外部环境的有效热绝缘，从而消除了额外的庞大的热绝缘设置的传统需要，并增加了对液流的响应。茎周围的多个液流测量的空间平均提高测量精度。通过使用传感器材料和结构的可拉伸性，传感器对植物生长的物理约束被最小化以用于长期监测。所提出的可穿戴传感器可以大规模和低成本制造，使其能够被纳入耐旱育种计划。最后，传感器的特点，校准和验证随着时间的推移，在温室中使用植物用水的重量测量。最初的试点实地测量进行，传感器被应用到几个玉米杂交种下灌溉和非灌溉条件下生长的基因组领域（现有的公私合作伙伴关系）的内布拉斯加州的贡献的一部分。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Breeding plants for increased drought resistance without sacrificing yield is a major goal of breeding efforts around the world. However, drought resistance and yield tend to be inversely correlated. The rate that water flows through the stalk of plants on its way to the leaves is a critical variable in explaining differences in drought tolerance between different varieties of plants. However, current technologies for measuring the rate of this flow are bulky and can damage the plant when they remain applied for long time periods; thus they are not able to monitor plants throughout a growing season. In addition, the data collected from current sensors requires measurements of stem size in order to accurately measure flow rates. If stems grow over the course of the experiment, these measurements can introduce error is. This project develops a wearable plant sensor that enables accurate long-term quantification of flow rates across many environments and genotypes. Large numbers of low-cost sensors can be deployed in breeding programs enabling direct evaluation of lines. From these lines specific genetic loci controlling variation in sap flow rates under different environmental conditions can be identified. Likewise data from these sensors can be used in genomic prediction models that prioritize new breeding lines prior to the investment of resources field trials. This research will enhance workforce development by providing research opportunities to next-generation researchers at the intersection of engineering and plant science. This collaborative project will integrate advances in sensors, microsystems, nanomaterials, and plant sciences to realize a novel sap flow measurement method that ultimately advances functional genomics research and the breeding of drought tolerant crops. The objective is to develop a wearable plant sensor for long-term, accurate, and affordable monitoring of sap flow over an entire growing season. The sensor design allows efficient thermal insulation of the microscale sap flow sensing unit from external environments, thus eliminating the traditional need of additional bulky thermal insulation setup and increasing the response to sap flow. Spatial averaging of multiple sap flow measurements around the stem enhances measurement accuracy. By using stretchability of the sensor materials and structures, physical constraints of the sensor on plant growth is minimized for long-term monitoring. The proposed wearable sensors can be manufactured at large scale and low cost, allowing it to be incorporated into breeding programs tolerating drought tolerance. Lastly, the sensors are characterized, calibrated and validated over time using gravimetric measures of plant water use in the greenhouse. Initial pilot field measurements are performed, where the sensors are applied to several maize hybrids grown under irrigated and non-irrigated conditions as part of the Nebraska contribution to Genomes to Fields (an existing public-private partnership).This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.