Lateral root production of witloof chicory (Cichorium intybus L.) in response to ebb-and-flood nutrient supply in hydroponics

Abstract

Witloof chicory is currently grown on a large scale by making use of gravity-driven hydroponic cascade systems. A possible drawback of this method may be that the taproot is only submerged in the nutrient solution to a depth of about 30 mm. Lateral roots are believed to be responsible for most nutrient and water absorption. It is commonly observed that most lateral roots emerge below the water line. For this reason it was hypothesised that it could be beneficial to raise the nutrient solution level, and by doing so, stimulate more root primordia to grow into fully functional absorptive lateral roots. When chicory roots were wetted to a greater depth by using an ebb- and-flood technique, an increase in lateral roots forming along the axes of the taproot resulted. Total lateral root production was quantified using a lateral root index. A significant increase was confirmed for one of the two cultivars tested when the root axes were wetted to a depth of 100 mm.