Chitooligosaccharide application enhanced the growth and phytoremediation efficiency of industrial hemp in Cd-contaminated soils.

Hemp has been widely used for cadmium (Cd) remediation. However, its remediation efficiency needs to be improved. Chitooligosaccharides can enhance plant resistance and growth; however, their effects on hemp for Cd-remediation remain unclear. Herein, a greenhouse pot experiment was conducted to investigate the effects of three doses (0, 22.5, and 45 μg m) of chitooligosaccharides (COS), chitin-oligosaccharides (NACOS), and hetero-chitooligosaccharides (HTCOS) on the growth and Cd-remediation efficiency of hemp. Results showed that chitooligosaccharides promoted the antioxidant system and aerial biomass (maximum 84 %) depending on doses and types. COS (22.5 μg m under 60 mg cadmium kg soil), NACOS, and HTCOS significantly elevated the Cd concentration in hemp. Consequently, NACOS and HTCOS (45 μg m) significantly increased the average Cd removal up to 61 % and 81 %, respectively, compared with the control. Therefore, spraying chitooligosaccharides can enhance growth and phytoremediation efficiency of hemp by elevating aerial biomass and cadmium concentration of hemp.