Salinity-driven oxidative stress in Gerbera jamesonii cv. Bolus

Abstract: Salinity adversely affects various plants’ metabolic processes, negatively influencing their productivity and crop yield. Gerbera jamesonii cv. Bolus is a commercially important ornamental plant cultivated globally throughout the year for its cut flower production in polyhouses. During polyhouse cultivation, repeated fertigation may cause salinity in Gerbera, affecting flower quality and yield, and functional alterations in the basal level of cellular antioxidative defence systems. Though several factors induce salinity in general, we focussed on NaCl as it is one of the major components of fertigation. In salt-stressed plants, monitoring altered levels of antioxidative defense systems may help better understand their physiological changes. However, little to no studies were attempted on salinity-induced oxidative damage in Gerbera till date. In the current study, we verified the salt sensitivity level of Gerbera with varying concentrations of NaCl (0-200 mM) using in vitro leaf disc approach. We measured various antioxidative enzymatic/non enzymatic defense systems besides MDA and chlorophyll content. Treatment with higher salt concentrations (above100 mM NaCl) exhibited severe bleaching in leaf discs, followed by elevated levels of H₂O₂, lipid peroxidation and proline. Besides, our study also revealed a decrease in the total chlorophyll content; activities of superoxide dismutase, catalase, glutathione reductase, and ascorbate peroxidase. The observed results showed that Gerbera might not tolerate higher levels of NaCl as it could be detrimental to its cellular activities. Future studies on decoding molecular networks associated with salinity stress and antioxidative defense systems may help in developing salt-tolerant varieties in Gerbera and several other ornamental plants of Asteraceae.