Mohamed Awaz, Monnier Yogan, Mao Zhun, Lobet Guillaume, Maeght Jean-Luc, Ramel Merlin, Stokes Alexia
AMAP, INRA, CNRS, IRD, Université de Montpellier, Montpellier, France.
Earth and Life Institute, Université catholique de Louvain, 1348 Louvain-la-Neuve, Belgium.
Plant Methods. 2017 Mar 7;13:11. doi: 10.1186/s13007-017-0160-z. eCollection 2017.
Belowground processes play an essential role in ecosystem nutrient cycling and the global carbon budget cycle. Quantifying fine root growth is crucial to the understanding of ecosystem structure and function and in predicting how ecosystems respond to climate variability. A better understanding of root system growth is necessary, but choosing the best method of observation is complex, especially in the natural soil environment. Here, we compare five methods of root image acquisition using inexpensive technology that is currently available on the market: flatbed scanner, handheld scanner, manual tracing, a smartphone application scanner and a time-lapse camera. Using the five methods, root elongation rate (RER) was measured for three months, on roots of hybrid walnut ( × L.) in rhizotrons installed in agroforests.
When all methods were compared together, there were no significant differences in relative cumulative root length. However, the time-lapse camera and the manual tracing method significantly overestimated the relative mean diameter of roots compared to the three scanning methods. The smartphone scanning application was found to perform best overall when considering image quality and ease of use in the field. The automatic time-lapse camera was useful for measuring RER over several months without any human intervention.
Our results show that inexpensive scanning and automated methods provide correct measurements of root elongation and length (but not diameter when using the time-lapse camera). These methods are capable of detecting fine roots to a diameter of 0.1 mm and can therefore be selected by the user depending on the data required.
地下过程在生态系统养分循环和全球碳预算循环中起着至关重要的作用。量化细根生长对于理解生态系统结构和功能以及预测生态系统如何应对气候变化至关重要。更好地了解根系生长是必要的，但选择最佳观测方法很复杂，尤其是在自然土壤环境中。在这里，我们使用市场上现有的廉价技术比较了五种根系图像采集方法：平板扫描仪、手持扫描仪、手工追踪、智能手机应用扫描仪和延时相机。使用这五种方法，对种植在农林复合系统根箱中的杂交核桃（×L.）根系进行了三个月的根伸长率（RER）测量。
当将所有方法放在一起比较时，相对累积根长没有显著差异。然而，与三种扫描方法相比，延时相机和手工追踪方法显著高估了根的相对平均直径。考虑到图像质量和在野外的易用性，发现智能手机扫描应用总体表现最佳。自动延时相机可用于在无需任何人工干预的情况下测量数月的根伸长率。
我们的结果表明，廉价的扫描和自动化方法能够正确测量根伸长和长度（但使用延时相机时不能测量直径）。这些方法能够检测到直径为0.1毫米的细根，因此用户可以根据所需数据进行选择。
