THE GROWTH AND SOLUTE ACCUMULATION OF SPARTINA ALTERNIFLORA SEEDLINGS IN NaCL SOLUTION OF DIFFERENT CONCENTRATION

The seedlings of Spartina alterniflora were grown in sand culture with different concentration Hoagland solution of NaCl, ranging from 50 to 400mmol/L. The amount of growth in 14th day was measured, and samples were collected. The samples were assayed for osmotic potential, inorganic ions, soluble sugar and free proline, The purpoes was to determinevhether any correlation existed between seedling growth and solute accumulation under salt-stress.The results showed that a large amount of Na⁺ and Cl^- were accumulated in seedlings in the solution containing NaCl, and the accumulation of soluble sugar and proline were accelerated. The contents of Na⁺ and Cl^- increased with enhanced concentration of external NaCl. The content of K⁺ slightly decreased in 50 mmol/L and incraesed in 100—400 mmol/L NaCl nutrient solution. Therefore the ratio of Na⁺ to K⁺ increased with enhanced concentration of external NaCl. Seedlings of Spartina alterniflora utilize Na⁺ and Cl^- as principial osmotiea. Inorganic ions opproximately account for 78—85% of the osmotic substanees, the soluble sugar and proline account for about 12—15% and 2—4.6%. The total content of accumulated inorganic ions in roots were higher than in shoots. Due to accumulation of solutes, the osmotic potential of pressed juice in shoots reduced with increased concentration of external NaCl.The fresh weight of seedlings was inhibited by external NaCl solution. Their dry weight was not markedly affeeted. The ratio of fresh weight/dry weight decreased with increased concentration of external NaCl.