A new root box for developing whole root systems in water culture

Abstract

We have established a new plant box made of phenolic resin foam for developing whole root systems in water culture, and examined its application to the detection of changes in pH and the distribution of nutrients in the rhizosphere. The root box is light and soft, providing the cultures with ample air. In well-washed resin sheets, little NH4-N, NO3-N or K remained. Also CEC was low and the pH of the supplied solutions did not change in the resin. Therefore, culture using the root box allows for nutrient solutions to maintain their own pH and concentration of NH4-N, NO3-N and K. In addition, the root box allowed better visualization of changes in pH and the distribution of nitrate by image analysis in a representative whole root system. The pH values were detected with pH indicators, and the nitrate concentrations with a color reagent, sprayed onto profiles of the root system. The method described here offers a new approach for developing the whole system in water culture and a simple way to obtain an overall view of changes in pH and the distribution of nutrients in the rhizosphere under water culture conditions.