Potassium silicate combined with glycine betaine improved salt tolerance in Dalbergia odorifera

Abstract

Salinity has a huge negative impact on plant growth and development by increasing sodium ions accumulation and potassium ions loss that deeply disturbs the plant cell homeostasis and can lead to plant cell death. The imbalance between Na+ and K+ could be solved by applying potassium silicate (K2SiO3). The glycine betaine (GB) is well-known to play a crucial role against oxidative stress in plants by improving the antioxidant machinery. Thus, this research aimed to apply K2SiO3 (1 mM) and GB (10 mM) alone or in combination against 200 mM NaCl-induced damages in Dalbergia odorifera. The results showed a significant amelioration of negative effects of salt stress on the phenotypic traits, chlorophyll content, net photosynthetic rate, stomatal conductance, transpiration rate, and water use efficiency by applied substances. The contents of saccharides and proline were down-regulated by K2SiO3, GB, and K2SiO3-GB, whereas the proteins content was increased by these treatments. The contents of lipid peroxidation, superoxide anion, hydrogen peroxide were reduced by exogenous substances under stress. The activities of antioxidant enzymes (superoxide dismutase, peroxidase, and catalase) and the accumulation of antioxidants (glutathione and ascorbate) were enhanced by exogenous substances. The K2SiO3-GB combination mostly showed better effects on antioxidant machinery compared to a single treatment.

Keywords

• antioxidants
• chlorophyll
• dalbergia odorifera
• glycine betaine
• oxidative stress
• photosynthesis
• potassium silicate
• redox homeostasis
• salt tolerance