Abstract
Petal cell death may be based on the increase in the reactive oxygen species and the reduction in defense enzymes. Moreover, in aging process, breakdown of DNA and proteins is observed. In this research, we analyzed PCD parameters related to senescence such as petal oscillation ability, the anti-oxidization system, the amount of ethylene evolution, the DNA fragmentation, the hydrogen peroxide content. Although opening-and-closing movement of a petal was active in early stage, this ability declined from the middle stage of aging. DNA fragmentation was started at the same stage and DNase and protease activities also increased simultaneously. Following DNA fragmentation, hydrogen peroxide content increased and finally rapid evolution of ethylene was observed. In parallel to this, decrease of the ascorbate peroxidase activity started. So, the aging process in tulip petals is the same PCD process as in animal cells.
