Arnaud Marie, Baird Andy J, Morris Paul J, Harris Angela, Huck Jonny J
1School of Geography, University of Leeds, Leeds, LS2 9JT UK.
2School of Environment and Development, University of Manchester, Manchester, M13 9PL UK.
Plant Methods. 2019 Aug 28;15:101. doi: 10.1186/s13007-019-0489-6. eCollection 2019.
Fine root production is one of the least well understood components of the carbon cycle in terrestrial ecosystems. Minirhizotrons allow accurate and non-destructive sampling of fine root production. Small and large scale studies across a range of ecosystems are needed to have baseline data on fine root production and further assess the impact of global change upon it; however, the expense and the low adaptability of minirhizotrons prevent such data collection, in worldwide distributed sampling schemes, in low-income countries and in some ecosystems (e.g. tropical forested wetlands).
We present EnRoot, a narrow minirhizotron of 25 mm diameter, that is partially 3D printable. EnRoot is inexpensive (€150), easy to construct (no prior knowledge required) and adapted to a range of ecosystems including tropical forested wetlands (e.g. mangroves, peatlands). We tested EnRoot's accuracy and precision for measuring fine root length and diameter, and it yielded Lin's concordance correlation coefficient values of 0.95 for root diameter and 0.92 for length. As a proof of concept, we tested EnRoot in a mesocosm study, and in the field in a tropical mangrove. EnRoot proved its capacity to capture the development of roots of a legume () and a mangrove species (seedlings of ) in laboratory mesocosms. EnRoot's field installation was possible in the root-dense tropical mangrove because its narrow diameter allowed it to be installed between larger roots and because it is fully waterproof. EnRoot compares favourably with commercial minirhizotrons, and can image roots as small as 56 µm.
EnRoot removes barriers to the extensive use of minirhizotrons by being low-cost, easy to construct and adapted to a wide range of ecosystem. It opens the doors to worldwide distributed minirhizotron studies across an extended range of ecosystems with the potential to fill knowledge gaps surrounding fine root production.
细根生产是陆地生态系统碳循环中最不为人所了解的组成部分之一。微根管可实现对细根生产的准确且非破坏性采样。需要在一系列生态系统中开展小规模和大规模研究，以获取细根生产的基线数据，并进一步评估全球变化对其产生的影响；然而，微根管的成本和低适应性阻碍了在全球分布的采样方案、低收入国家以及某些生态系统（如热带森林湿地）中收集此类数据。
我们展示了EnRoot，一种直径为25毫米的窄型微根管，它部分可以3D打印。EnRoot价格低廉（150欧元），易于构建（无需先验知识），并适用于包括热带森林湿地（如红树林、泥炭地）在内的一系列生态系统。我们测试了EnRoot在测量细根长度和直径方面的准确性和精确性，其直径的林氏一致性相关系数值为0.95，长度为0.92。作为概念验证，我们在中宇宙研究和热带红树林实地对EnRoot进行了测试。EnRoot证明了其在实验室中宇宙中捕捉豆科植物和红树林物种（的幼苗）根系发育的能力。EnRoot能够在根系密集的热带红树林中进行实地安装，因为其窄直径使其能够安装在较大根系之间，并且它完全防水。EnRoot与商业微根管相比具有优势，并且能够成像小至56微米的根系。
EnRoot通过低成本、易于构建且适用于广泛的生态系统，消除了微根管广泛应用的障碍。它为在更广泛的生态系统中开展全球分布的微根管研究打开了大门，有可能填补围绕细根生产的知识空白。
