| Abstract:In this study, tomato(Solanum lycopersicum L.) cultivar ‘Zhongza No. 9’ was used as experimental material, 80 mmol/L Ca(NO3)2 was conducted to simulate the soil secondary salinization in protected agriculture, and(800±40) μmol/mol was used to simulate the CO2 enrichment environment. The effects of CO2 enrichment on the growth and osmotic regulation characteristics in tomato seedling exposed to salt stress were investigated. The results showed that compared with control treatment, salt stress significantly inhibited tomato growth. The leaf relative water content and water potential, the root hydraulic conductance, morphological parameters and osmotic potential were also decreased to different extent. Meanwhile, the soluble sugar mass fraction in leaves, the free amino acid and proline mass fraction in plants were increased significantly, but the soluble protein mass fraction in leaves, the organic acid mass fraction in plants were significantly decreased. In comparison with single salt treatment, CO2 enrichment significantly improved the dry and fresh quality, leaf water potential, root length, root surface area, root volume and root osmotic potential in salt-stressed plant. Besides, the mass fraction of soluble protein, proline and organic acid in leaves were significantly increased by 111.99%, 10.93% and 14.62%, respectively, while the mass fraction of soluble protein and free amino acid in roots were significantly increased by 76.01% and 76.97%, respectively, and the proline mass fraction in roots were significantly lowered by 6.33%. In conclusion, CO2 enrichment could enhance the salt tolerance of tomato seedlings by improving the water status and osmotic adjustment capacity of the plants, especially promoting the accumulation of soluble protein. |
