The present study was carried out to investigate the role of spermidine (Spd) in alleviating salinity stress in an ornamental plant, Gerbera jamesonii cv Bolus ex Hook. f. From our laboratory studies, we could establish that G. jamesonii plants grown in a polyhouse are hugely exposed to salts due to repeated fertigation and differ in their sensitivity toward salt stress. In the present study, we have assessed changes in the salinity tolerance levels across G. jamesonii genotypes when treated with exogenous supplementation of Spd. The sodium chloride (NaCl) sensitive (white), moderately sensitive (pink), and tolerant (yellow) G. jamesonii varieties were subjected to 200 mM NaCl treatment followed by an exogenous foliar spray of Spd (1.0 mM). Our findings revealed that Spd treatment increased leaf growth, soluble protein, proline, chlorophyll content and lowered lipid peroxidation, and hydrogen peroxide accumulation. Enhanced enzyme activities of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase following treatment with Spd suggest its role in conferring salt tolerance in G. jamesonii genotypes. Supplementation of 1.0 mM Spd has drastically improved efficiency of photosynthesis by minimizing salt stress initiated cellular injury by scavenging highly reactive oxygen radicals.
Key words: Abiotic stress; Antioxidant defenses; Gerbera; ROS; Salinity; Spermidine
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