Physiological and biochemical responses of gerbera (Gerbera jamesonii Hook.) to physical and chemical mutagenesis

Abstract

SummaryThe physiological effects of physical and chemical mutagenesis on in vitro-raised plants of Gerbera jamesonii Hook. were investigated. In vitro cultures of gerbera were established through capitulum explants cultured on 1.0× Murashige and Skoog (MS) medium supplemented with 5 mg l–1 benzyladenine (BA) and 0.5 mg l–1 indole-3-acetic acid (IAA). In vitro-regenerated shoots were treated separately with ethyl methyl sulphonate (EMS) at 0.1, 0.2, 0.5, 0.8, or 1.0% (v/v) or γ-irradiation (at doses of 1.5, 2.0, 2.5, 5.0, or 10.0 Gy). The activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione reductase (GR), catalase (CAT), and polyphenol oxidase (PPO) increased significantly compared to untreated control shoots and reached a maximum at the highest dose of either mutagen. Overall, 18.3% and 20.5% reductions in chlorophyll concentration were observed in 2 month-old hardened plants following γ-irradiation or EMS treatment, respectively. The mutated shoots showed significant increases in total phenolic compound concentrations (36% and 21.7%) and total protein concentrations (17.6% and 17.1%) at the highest dose of γ-rays or EMS, respectively. Increases in the activities of the five enzymes, and in the concentrations of phenolic compounds and proteins, indicated the importance of these biomolecules in protecting gerbera plants grown under abiotic stress conditions.