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

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. • The research explores the untapped potential of dynamic mechanical stimulation in shaping root architecture, revealing its significant impact on root growth dynamics in an elastic hydrogel environment. • A transparent and resilient GG/PAM double network hydrogel offered a novel cultivation medium that permits direct visualization of root responses to stimuli and withstands extrinsic forces without damaging the delicate root structures. • Through reciprocating extrusion, this study demonstrates a marked increase in lateral root formation, highlighting the potential to artificially modulate root branching, a key factor in enhancing nutrient uptake and anchorage strength. • The study elucidates how mechanical perturbations can be harnessed to engineer root phenotypes that display heightened adaptability to diverse soil conditions, thereby advancing strategies for crop improvement and sustainable agriculture.