Effects of silicon on salinity tolerance of two barley cultivars

Added silicon (Si) could significantly enhance dry matter yields of both salt-sensitive (Hordeum vulgare L. Kepin No. 7) and salt-tolerant (Hordeum vulgare L. Jian 4) barley cultivars under salt-stressed condition. The dry matter yield of Kepin No.7 grown in the solution containing high Si (1.0 mM Si/L) and high salt (120 mM NaCl/L) was 18.0% greater than that of the plants treated with 120 mM NaCl/L alone. The dry matter yield of Jian 4 treated with low Si (0.5 mM Si/L) and high salt (120 mM NaCl/L) was found to increase by 15.2% compared with that of plants treated with 120 mM NaCl/L only. Silicon added could increase net photosynthetic rate of two barley cultivars grown in the solution containing 120 mM NaCl/L. The electrolytic leakage percentage was significantly lower in the leaves of two barley cultivars treated with 120 mM NaCl/L and 1.0 mM Sin, than in the leaves treated with 120 mM NaCl/L alone, which indicated that added Si resulted in a reduction of membrane permeability of salt-stressed barley. Silicon could enhance the uptake of potassium (K) and inhibit the uptake of sodium (Na) by salt-stressed barley, thus mitigating the toxicity of salt to barley and increasing salt tolerance of the plants.