Duckweed has been considered as a renewable feedstock for bioethanol production due to its fast generation of biomass and high starch accumulation. The use of plant hormones is a common and efficient method to manipulate plant growth and yield. However, the effects of different plant hormones on the biomass and starch accumulation of duckweed have not been systematically studied. Here, we screened five classes of plant hormones, including auxin, cytokinin, abscisic acid (ABA), gibberellins, and brassinosteroids. The results showed that the effect of 6-benzylaminopurine (6-BA, cytokinin) on promoting the biomass production of duckweed was much higher than other plant hormones. Compared with the control group, biomass yield at 1.0 x 10(-3) mM 6-BA treated group increased by 37.41% in 7 days. Moreover, the results suggested that ABA can dramatically promote starch accumulation. The total starch that accumulated in the ABA treated samples were 3.3 times higher than that in the control samples. Taken together, these findings indicated that 6-BA and ABA were the most effective plant hormones in terms of enhancing biomass and starch accumulation. These results will provide valuable information for further studies of large-scale application of plant hormones in duckweed-to-bioethanol production in the future. (C) 2019 Elsevier Ltd. All rights reserved.