Cuminaldehyde, a cumin seed volatile component, induces growth inhibition, overproduction of reactive oxygen species and cell cycle arrest in onion roots

•Cuminaldehyde showed strong phytotoxicity in several plant species including onion.•Cuminaldehyde induced O2− production and cessation of cell division in onion roots.•Cuminaldehyde also induced DNA damage, programmed and necrotic cell death in onion.