Review on new methods of in situ observation of plant micro-roots and interpretation of root images

Root system plays key roles in fixing plants, obtaining water and nutrients for plants. As a hub connecting plant shoots and soil environment, the development of root system determines the formation of the aboveground part. Micro-root system is the main execution site of root function, consists of fine roots and root hairs. Due to the non-intuitive nature of the roots and complex stereo configuration of the root system in the soil, conventional research methods are ineffective for observing the real morphology of root systems. In-situ and non-destructive methods have been attempted and attracted more and more attention in present years. The main types of in-situ and non-destructive devices that can be used to observe the 2D morphology and stereo configuration of micro-roots, and some root image analysis software were introduced and evaluated for efficient use of them in root research.