Fluidics-based plant study platform with colorimetric humidity monitoring

Studying plant root responses to various environmental stimuli is challenging due to lack of proper and convenient methods for analysis. By adopting the concept of microfluidic systems, we develop a novel meso-scale fluidic platform to create controlled environment for studying physiological behaviors of small plant roots. Air flows with different humidity through a Y-shape fluidic channel generate a two-dimensional humidity gradient over the root zone of a small plant. The gradient was monitored with embedded humidity sensors. Actively growing plant roots are directly exposed to this humidity gradient and their growth kinetics are analyzed. This simple fluidic platform proved to be very effective and promising to investigate hydrotropic responses of plant roots (i.e. root bending toward a more humid region). We anticipate that this platform can be applied to other areas of plant research including metabolic and genetic engineering.