Engineering living root with mechanical stimulation derived from reciprocating compression in a double network hydrogel as elastic soil

Abstract

The root system actively reacts to mechanical stimuli in its environment, transmitting mechanical signals to optimize the utilization of environmental resources. While the mechanical impedance created by the growth medium serves as the primary source of stimulation for the roots, extensive research has focused on the roots' response to static mechanical stimulation. However, the impact of dynamic mechanical stimulation on root phenotype remains underexplored. In this study, we utilized a low acyl gellan gum/polyacrylamide (GG/PAM) double network elastic hydrogel as the growth medium for rapeseed. We constructed a mechanical device to investigate the effects of reciprocating extrusion stimulation on the growth of the rapeseed root system. After three weeks of mechanical stimulation, the root system exhibited a significant increase in lateral roots. This branching enhanced the roots' anchoring and penetration into the hydrogel, thereby improving the root system's adaptability to its environment. Our findings offer valuable data and insights into the effects of reciprocating mechanical stimulation on root growth, providing a new way for engineering root phenotype.