Activated-carbon-filled agarose hydrogel as a natural medium for seed germination and seedling growth

An activated-carbon-filled agarose (Agar-AC) hydrogel containing various concentrations of activated carbon (AC) was successfully fabricated through a simple solvent cast technique. Compared to pure agarose hydrogels, Agar-AC hydrogels exhibited excellent mechanical properties, good thermal stability and a highly developed pore structure. The Agar-AC hydrogels also showed a certain degree of improvement in water retention performance, while their swelling ratio decreased with the addition of AC. The incorporation of AC did not influence the crystallinity of the agarose hydrogel, and no chemical modification occurred according to XRD and FTIR. In rapeseed seed germination experiments, the growth indexes of rapeseed, including the germination percentage, root length, stem length, fresh weight and dry weight, were enhanced by the incorporation of a suitable amount of AC. These results indicated that AC has great potential to enhance the properties of agarose hydrogels and improve seed germination and plant growth, which implies that Agar-AC hydrogels can be used as natural materials for agricultural applications.