Dehydration is a major factor resulting in huge loss from cut flowers during transportation. In the present study,
dehydration inhibited petal cell expansion and resulted in irregular flowers in cut roses, mimicking
ethylene-treated flowers. Among the five floral organs,
dehydration substantially elevated
ethylene production in the sepals, whilst
rehydration caused rapid and elevated
ethylene levels in the gynoecia and sepals. Among the five
ethylene biosynthetic
enzyme genes (RhACS1-5), expression of RhACS1 and RhACS2 was induced by
dehydration and
rehydration in the two floral organs. Silencing both RhACS1 and RhACS2 significantly suppressed
dehydration- and
rehydration-induced
ethylene in the sepals and gynoecia. This weakened the inhibitory effect of
dehydration on petal cell expansion. β-
glucuronidase activity driven by both the RhACS1 and RhACS2 promoters was dramatically induced in the sepals, pistil, and stamens, but not in the petals of transgenic Arabidopsis. This further supports the organ-specific induction of these two genes. Among the five rose
ethylene receptor genes (RhETR1-5), expression of RhETR3 was predominantly induced by
dehydration and
rehydration in the petals. RhETR3 silencing clearly aggravated the inhibitory effect of
dehydration on petal cell expansion. However, no significant difference in the effect between RhETR3-silenced flowers and RhETR-genes-silenced flowers was observed. Furthermore, RhETR-genes silencing extensively altered the expression of 21 cell expansion-related downstream genes in response to
ethylene. These results suggest that induction of
ethylene biosynthesis by
dehydration proceeds in an organ-specific manner, indicating that
ethylene can function as a mediator in
dehydration-caused inhibition of cell expansion in rose petals.