Abscisic acid and reactive oxygen species were involved in slightly acidic electrolyzed water-promoted seed germination in watermelon

•SAEW could promote seed germination of watermelon.•The endogenous phytohormone analyses revealed the positive role of SAEW in reducing ABA accumulation in watermelon seeds.•The qRT-PCR analyses revealed that SAEW induced the transcriptional level of genes involved in ABA catabolism.•The reduction of ROS accumulation may give rise to the germination in advance caused by SAEW.