Photodynamic damage to plant leaf tissue by rose bengal

Abstract

The photodynamic action of the xanthene dye rose bengal upon pea leaf tissue was investigated. Irradiation of pea leaf discs treated with aqueous solutions of the sensitizer resulted in the loss of chlorophyll. Irradiation through a filter of rose bengal solution did not result in chlorophyll loss. The loss of chlorophyll was dependent upon light intensity and oxygen levels. The enchancement of pigment loss in leaf discs supplied with deuterium oxide (D₂O) supports a photodynamic mechanism involving singlet oxygen (¹O₂).