Abstract
The relation between radical production and acute morphological changes of palisade cells of Saintpaulia induced by a rapid drop in leaf temperature was investigated. The drastic and apoptotic changes were observed immediately after the chilling treatment for 3 sec. OH radical production occurred immediately after the chilling treatment and then increased linearly depending on the time. The radical production might initiate and develop acute irreversible morphological changes resulting in apoptotic cell death of Saintpaulia palisade cells.