Demonstration for Non-destructive Root Growth Measurement at Hydroponic Culture by Using a Root Imager

We demonstrate a nondestructive root growth measurement technique under hydroponic culture conditions. Recently, a root imager that can measure the root length, root surface area, and root volume in the field has been developed. We applied this instrument to hydroponic culture conditions and demonstrated successful nondestructive tomato root growth measurement during a course of growth. First we manufactured suitable hydroponic systems for root imager measurement. We transplanted tomato seedlings into this system and took root images by using a root imager every 3 days, and then analyzed those images by using a root scanner. We demonstrate that it was possible to detect root growth continuously and the measurements were correlated with that of root dry weights. Then we measured tomato root growth under the salt and metal stresses treatment. We used a concentrated hydroponic culture solution or applied a aluminum chloride into culture solution for tomato culture. We detected decreased root growth at these conditions. As a result, this measurement technique is applicable for in situ root analysis in hydroponic culture. Further research needs to have more physiological and morphological experiments.