Silicon-mediated changes of some physiological and enzymatic parameters symptomatic for oxidative stress in spinach and tomato grown in sodic-B toxic soil

Abstract

We investigated effect of silicon (Si) on the growth, uptake of sodium (Na), chloride (Cl), boron (B), stomatal resistance (SR), lipid peroxidation (MDA), membrane permeability (MP), lipoxygenase (LOX) activity, proline (PRO) accumulation, H 2 O 2 accumulation, nonenzymatic antioxidant activity (AA) and the activities of major antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT and ascorbate peroxidase, APX) of spinach and tomato grown in sodic-B toxic soil. Si applied to the sodic-B toxic soil at 2.5 and 5.0 mM concentrations significantly increased the Si concentration in the plant species and counteracted the deleterious effects of high concentrations of Na, Cl and B on root and shoot growth by lowering the accumulation of these elements in the plants. Stomatal resistance, MP, MDA and the concentrations of H 2 O 2 and PRO were higher in the plants grown in sodic-B toxic soil without Si: LOX activity of excised leaves of both species was increased by Si. Antioxidant activities of both species were significantly affected by Si, with the activities of SOD, CAT and APX decreased and AA increased by applied Si. For most of the parameters measured, it was found that 5 mM Si was more effective than the 2.5 mM Si. Based on the present work, it can be concluded that Si alleviates sodicity and B toxicity of the plants grown in sodic-B toxic soil by preventing both oxidative membrane damage and also translocation of Na, Cl and B from root to shoots and/or soil to plant, and lowering the phytotoxic effects of Na, Cl and B within plant tissues. It was concluded that tomato was more responsive to Si than spinach since it was more salt sensitive than spinach. To our knowledge, this is the first report that Si improves the combined salt and B tolerance of spinach and tomato grown in naturally sodic-B toxic soil, and which describes membrane-related parameters and antioxidant responses.

Regulation of Growth, Antioxidants and Sugar Metabolism in Rice (<i>Oryza sativa</i> L.) Seedlings by NaCl and Its Reversal by Silicon

“…This study showed that lipid peroxidation induced by NaCl was lower in the Si-treated rice seedlings under salt stress than those under salt stress without Si treatment, which revealed protection of lipid membranes from ROS [47], primarily by more effective scavenging of ROS by means of Si application. Similarly, Si application decreased malondialdehyde and H 2 O 2 contents in spinach and tomato plants grown in sodic-B toxic soil [48].…”

Regulation of sugar metabolism in rice (Oryza sativa L.) seedlings under arsenate toxicity and its improvement by phosphate

“…The application of phosphate simultaneously with arsenate ameliorate to some extent the damaging effect caused by arsenic toxicity. Therefore, the use of phosphate enriched fertilizers in arsenic contaminated soils may improve the health with better sugar metabolizing activity as well as production of rice plants, but the concentration of phosphorus in fertilizers should be carefully considered (Gunes et al, 2008).…”

The effect of foliar fertilization with marine calcite in sugar beet

“…However, the role of silicon in crops is not particularly well understood (Casey et al 2003). Silicon plays a very important role in the reduction of the plants vulnerability to biotic and abiotic environmental stress (Fauteux et al 2005, Mitani and Ma 2005, Ma and Yamaji 2006, Liang et al 2006, Gunes et al 2007, Sacała 2009). This component increases the plants' resistance to pathogens and pests (Samuels et al 1993, Fawe et al 1998, Raven 2003, Henriet et al 2006, Cai et al 2009).…”